Servicio de Corrección Bibliográfica

Descripción y análisis económico-financiero de la producción ovina en la Estación Experimental Facultad de Agronomía Salto

Matías Alexander Dávila Álvez — 2026-07-14

The sheep sector has historically been characterized by its economic and social importance in the country’s development. However, its presence across the territory has declined over the last 30 years due to several factors, mainly economic in nature, associated with changes in markets, the emergence of substitute fibers, and the evolution of consumer preferences. These processes have shaped the development of the sector, promoting increasing productive specialization, particularly towards fine wool production. In this context, economic analysis is essential for understanding the sector’s performance under variable productive and market conditions.

This study focused on analyzing the gross margin of the sheep production subsystem at the Experimental Station of the Faculty of Agronomy in Salto (EEFAS), Universidad de la República (UdelaR). The objectives were to determine whether the economic results were explained by internal system factors or by market conditions, as well as to position the obtained results within the range of possible outcomes over six agricultural years.

The methodology consisted of analyzing the productive structure of the system and its economic performance based on accounting records. In addition, the behavior of product and input markets was evaluated. Complementarily, Monte Carlo simulations were carried out for each production year using XLRISK (Vose Software, 2021) software in order to estimate the probabilistic distribution of gross margin and identify the main factors influencing the economic outcome.

The results revealed marked variability among years, with both positive and negative outcomes depending on productive conditions and price contexts. Sensitivity analysis for the average production year indicated that wool price and labor costs were the principal factors affecting the system’s gross margin. To a lesser extent, variables associated with meat marketing (price per kilograms and animal weight) showed a greater impact than supplement price. Overall, the system presented an average gross margin of USD 11/ha, accompanied by high variability. This economic result was found within the 90% probability range of occurrence.

In conclusion, despite the productive results achieved by the system, the final economic performance is strongly influenced by market factors. In a context of price fluctuations, economic results exhibited similar behavior. In this regard, the adoption of process technologies and the strategic use of inputs may enhance results under favorable market scenarios. These findings highlight the importance of appropriate management of productive resources and continuous monitoring of market conditions in order to improve the economic stability of the system. Specialization in fine wool production, together with diversification into new markets such as sheep genetics, constitutes a relevant aspect for improving the profitability of the evaluated system.

Rendimiento y calidad de flores de cáñamo (Cannabis sativa l.) según cultivar y fecha de trasplante

Federico Gabriel Llopis Leites — 2026-07-07

Understanding the response of cannabis varieties (Cannabis sativa L.) to different production management practices, both established and under development, may provide practical solutions to current productive and commercial constraints within the sector. In Uruguay, cannabis cultivation faces significant limitations related to production costs, making producers highly dependent on crop performance in each season to ensure continuity of cultivation in subsequent years. The objective of this study was to generate information on the optimal transplanting and/or harvesting periods of two cannabis varieties, Early Trump (Early T) and Jim’s Saparot (Jim’s S), which have contrasting growth cycles and were used as references for widely cultivated varieties in the country. Three transplanting dates were established for both varieties: November 30, 2023; December 20, 2023; and January 10, 2024, in order to evaluate photoperiod response in terms of yield (kg/ha) and commercial quality (A/B flower categories). The experiment was conducted in the department of Canelones, Uruguay, at the Germinare company’s field during the 2023–2024 growing season. A randomized complete block design (RCBD) with split plots was used, with subplots consisting of 16 plants as the experimental unit. Vegetative growth variables potentially related to yield were measured, including plant height, canopy diameter, and photosynthetically active radiation (PAR) interception. At harvest, quality traits such as flower size and compactness were assessed to determine commercial categories A and B. Yield and quality were evaluated after drying, with commercial standards requiring a final moisture content of 14%. Results showed that the longer-cycle variety, Jim’s S, achieved higher commercial yields across all transplanting dates. This response was largely explained by the positive correlation between vegetative growth variables—plant height, canopy diameter, and PAR interception—and the yield of category B flowers. Additionally, the latest transplanting date for both varieties showed a higher proportion of category A flowers relative to category B, accompanied by a lower vegetative biomass. Management of transplanting date and varietal selection can significantly influence labor use for crop maintenance, harvest, and post-harvest handling, thereby reducing production costs and increasing the likelihood of commercialization based on quality.

Evaluación nutricional y funcional de la harina de Camelina (Camelina sativa L. Crantz) en la dieta de gallinas ponedoras en la performance, calidad tecnológica y funcional del huevo

Agustín Souza castro — 2026-07-06

Egg production has undergone significant advances in recent decades due to genetic selection and improved management practices, extending the productive cycle to more than 80 weeks. However, the limits reached in productive performance, together with the increased age of laying hens, have intensified interest in nutritional strategies aimed at optimizing performance, health, and egg quality. In this context, the search for alternatives to soybean meal has gained importance due to its environmental impact, competition with human food use, and contribution to production costs. Camelina sativa, an oilseed crop with a high content of protein, unsaturated fatty acids, and bioactive compounds, and particularly its industrial by-product camelina meal, has potential as an alternative ingredient to soybean meal. The aim of this study was to evaluate the effect of including camelina meal in laying hen diets on productive performance, egg quality, and antioxidant status. A total of 56 Novogen Brown laying hens, 81 weeks of age, were allocated to four dietary treatments with different inclusion levels of camelina meal (0, 5, 10, and 15%). During a 28-day experimental period, feed intake per hen per day, egg production, and egg weight were recorded. In addition, internal and external egg quality, yolk phenolic and flavonoid content, and plasma oxidative status using TBARS as an indicator of lipid peroxidation were evaluated. The results showed that camelina meal inclusion at 5–10% tended to improve feed intake and egg weight. Higher inclusion levels increased the concentration of polyphenols and flavonoids in both fresh and stored egg yolks, while reducing plasma malondialdehyde (MDA) levels. However, the 15% inclusion level significantly reduced feed intake and egg production. Higher levels of camelina meal were associated with a decrease in plasma lipid peroxidation. These findings suggest that moderate inclusion levels of camelina meal represent a viable alternative to soybean meal in laying hen nutrition, contributing to the diversification of protein sources and the production of eggs with enhanced nutritional value.

Efecto de la nutrición materna durante la gestación sobre la calidad de la carne y la expresión génica muscular en corderos

Ana Cecilia Vidal Cardozo — 2026-06-25

Sheep production in Uruguay is primarily carried out in extensive systems on native pastures, where forage availability and quality vary seasonally. This situation is particularly relevant during gestation, as nutritional restrictions can affect fetal development and induce fetal programming processes with persistent effects on the offspring's productive performance. Since myogenesis occurs in the early stages of gestation, focused supplementation during critical periods could improve productive efficiency and lamb meat quality. The aim of this study was to evaluate the effect of protein supplementation between days 55 and 80 of gestation on the expression of genes associated with muscle development (MyHC-I, IGF1, and PAX7) and meat quality in the offspring, also considering the effect of sex and its interaction with the treatment. The study was conducted at Estación Experimental Bernardo Rosengurtt (FAGRO, UdelaR) during winter-spring 2023. Thirty-seven multiparous Corriedale ewes with singleton pregnancies and their respective lambs were used, distributed into two treatment groups: protein supplementation (SUP) and control (CON). Ewes grazed on native pasture and received (SUP) or no (CON) daily individual supplementation with soybean meal (1% of body weight) between days 55 and 80 of gestation. Lambs were raised until slaughter at 90 days of age. Samples were obtained from the Longissimus lumborum (LL), Gluteobiceps (GB), and Supraspinatus (SS) muscles for gene expression analysis using RT-qPCR and meat quality determinations. Statistical analysis was performed using mixed models considering the effects of treatment, sex, and their interaction. Maternal protein supplementation affected the expression of genes linked to muscle development in LL and GB, with no effect in the SS. The SUP treatment reduced the expression of MyHC-I (p = 0.01), PAX7 (p = 0.01), and IGF1 (p = 0.03) in GB, and tended to reduce the expression of MyHC-I (p = 0.07) and PAX7 (p = 0.09) in LL. Furthermore, in LL, MyHC-I expression tended to be influenced by the treatment × sex interaction (p = 0.08), with a reduction observed only in SUP males (p = 0.07). In LL, a trend toward lower pH at 24 h postmortem was observed in the SUP group. In GB, treatment effects were detected for color traits, with treatment × sex interactions in a*, b*, and C*, and a trend toward greater cooking losses in the SUP group. In SS, supplementation increased meat lightness (L*) and tended to interact with sex for shear force. Overall, the results indicate that protein supplementation during gestation can modulate muscle gene expression and affect meat quality in a muscle- and sex-dependent manner in the offspring, thus demonstrating the potential of maternal nutrition to influence skeletal muscle programming in pasture-based sheep systems.

Identification of resilient Texel animals through the study of live weight and feed intake trajectories

Fernanda Marchezan Barchet — 2026-06-24

In the last few years, the concept of animal resilience has gained increasing attention in livestock production. One of the reasons is the contribution of climate change, which has intensified the frequency and severity of extreme weather events. In semi-extensive or extensive systems, animals are daily exposed to diverse environmental challenges that are often beyond farmers’ control. Exposure to such challenges can affect animal behavior, health, welfare and productivity. Animals differ in their ability to cope with perturbation, resulting in varying levels of resilience. Evidence suggests that resilience has a potential trade-off with production, which means that the intense selection done over the past years for improving productive traits may have reduced animals’ adaptative capacity and robustness. Despite its relevance for commercial livestock systems, resilience is not a directly measured trait, which difficult its quantification. It has been hypothesized that high-frequency data can capture animals’ responses to different challenges, and the expansion of precision livestock farming tools have generated large amount of detailed data, however, the main challenges rely in developing accurate methodologies capable of transforming this kind of data into meaningful resilience indicators. In this sense, the objective of this study was to develop resilience indicators derived from high-frequency body weight and feed intake phenotypes and to investigate the associations with productive traits to explore potential antagonisms. More than 30 resilience indicators were generated using different approaches and methodologies. Results of phenotypic correlation showed that production and resilience have antagonistic associations, particularly when considering residual feed intake trait.

Forrajeo de polen, de las abejas melíferas (Apis mellifera) en contacto con cultivos de soja (Glycine max) en dos departamentos de Uruguay

Ana Paula Soca Huertas — 2026-06-11

This study aimed to assess and compare the pollen floral resources used by Apis mellifera colonies in different soybean production environments in Uruguay, using palynological techniques. Pollen samples were collected periodically from hives located in two sites (Mendoza, Florida and Young, Río Negro) using pollen traps at the hive entrance. The collected samples were analyzed to identify pollen types and were complemented with floral surveys of plant species present in the surrounding area. The results showed that A. mellifera uses soybean pollen during the flowering period, although not exclusively, as a wide diversity of co-flowering plant species was recorded. This multifloral pattern was consistent across both environments, reflecting the generalist foraging behavior of the species. In conclusion, soybean acts as a complementary pollen resource within the agricultural landscape, while the diversity of surrounding flora plays a key role in colony nutrition. Additionally, the presence of multiple attractive plant species may limit the concentration of foraging on soybean, potentially affecting pollination efficiency.

Fertirriego nitrogenado y su efecto en el rendimiento de maíz

Matias José Gallinal Fossati — 2026-06-04

Corn plays a key role in Uruguay’s production systems, mainly as an input for animal feed. Its yield largely depends on the availability of water and nutrients, especially nitrogen. In systems with supplemental irrigation, the management of nitrogen fertilization through fertigation can improve nutrient use efficiency by synchronizing its availability with crop demand. However, the effect of splitting nitrogen applications on corn yield shows variable results depending on environmental and management conditions. The objective of this study was to evaluate the effect of different nitrogen rates and levels of application splitting through fertigation on yield components and grain yield of corn under supplemental irrigation conditions. The experiment was conducted during the 2023/2024 growing season at the “Estación Experimental Mario A. Cassinoni” (EEMAC) of the Facultad de Agronomía, located in Paysandú, Uruguay. The trial was established under irrigated conditions, except for the control treatment. Different nitrogen rates and application splitting schemes were evaluated throughout the crop cycle. Measurements included dry matter accumulation, grain yield, and numerical components and subcomponents of yield. The data obtained were statistically analyzed using Info Stat software. The results showed that increasing nitrogen rates had a positive effect on crop growth and grain yield, confirming that greater nutrient availability promotes biomass formation and yield components. In particular, higher dry matter production and improvements in the number of grains per ear and grain weight were observed as the applied rate increased. In contrast, increasing the number of nitrogen application splits did not generate consistent increases in yield within each evaluated rate. In some cases, especially at high nitrogen rates, greater splitting even led to yield reductions, possibly associated with nutrient losses or lower efficiency in nutrient use by the crop. The results indicate that corn yield under irrigation primarily responds to the applied nitrogen rate, while increasing the number of application splits does not necessarily improve productivity.

Descripción y análisis de la cadena de valor de la carne vacuna de base pastoril en Uruguay

Maiko Hailton Ruff Rochon — 2026-06-04

This thesis describes and analyzes the pasture-based beef value chain in Uruguay for the 2023/2024 agricultural year. Its main objective is to quantify the Gross Value Added (GVA) generated by the chain and its distribution across phases, while a complementary objective is to represent and define the boundaries of the chain under a strict assumption, namely pasture-based cattle production. The production systems included in the study are cow-calf, rearing, finishing, and full-cycle systems, excluding animals finished in feedlots.

The main phases and actors are identified (input supply phase, agricultural phase, industrial phase, transportation, exports, imports, and government), and the costs (intermediate consumption) and Gross Production Value (GPV) of each phase are described, quantified, and analyzed. The results are organized in an input-output matrix specifically designed for the pasture-based chain, using information from public institutions and sectoral sources. For the agricultural year under study, the pasture-based beef value chain generates a GPV of USD 6.112 billion and costs of USD 3.426 billion, resulting in a total GVA of USD 2.686 billion and a GVA/GPV ratio of 43.9%.

The agricultural phase is the main generator of value, accounting for around 57% of total GVA, followed by the input supply phase, while the industrial and transportation phases contribute a smaller but still relevant share. The government captures part of the GVA through specific and consumption taxes.

Aplicación de deshojado en prefloración en las variedades Syrah y Tannat

Matías Gelabert Gutiérrez — 2026-06-03

This study evaluated the effect of preflowering leaf removal (DPF) and the application of Prohexadione calcium (PCa) on vegetative development, yield components, grape composition, sanitary status, and berry skin histological structure in the grapevine cultivars Tannat and Syrah under the edapho-climatic conditions of southern Uruguay. The effect of the treatments on vegetative parameters was generally limited, although some differences were observed. Potential exposed leaf area showed no significant differences among treatments within each cultivar but differed between cultivars, with higher values in Syrah. The proportion of exposed clusters also did not differ significantly among treatments in both cultivars. The number of leaf layers remained within optimal ranges; however, in Syrah the treatments reduced canopy density compared with the control. Regarding yield components, the number of clusters per plant was not affected by the treatments, indicating that differences were mainly determined by genotype, with higher cluster numbers in Syrah. Average cluster weight showed no significant differences, although slight decreasing trends were observed under Prohexadione calcium in Syrah and under pre-flowering leaf removal in Tannat. Yield per plant was not significantly modified by the treatments, and Syrah exhibited higher productivity than Tannat. Prohexadione calcium significantly reduced berry weight in Syrah, whereas pre-flowering leaf removal did not produce significant changes. In Tannat, however, early leaf removal significantly reduced berry size. Physiological responses related to cluster compactness were not statistically significant. Berry growth followed a normal developmental pattern, although in Syrah the application of Prohexadione calcium limited final berry growth. With respect to berry composition, soluble solids increased normally during ripening, with no differences among treatments at harvest. Total acidity decreased progressively in both cultivars without final differences among treatments, while pH increased throughout ripening and was only slightly affected by the treatments. Phenolic composition showed cultivar-dependent responses: in Tannat, anthocyanin potential and total polyphenol index increased following early leaf removal, whereas in Syrah the responses were more moderate. The histological structure of the berries, specifically cuticle thickness, epidermis thickness, hypodermis thickness, and total epicarp thickness, did not show significant differences among treatments or between cultivars, indicating a strong structural stability of these tissues. However, the number of skin cells displayed a differential response within each cultivar. In Tannat, the highest values were observed in the control treatment and decreased under early leaf removal, while in Syrah the treatments, particularly Prohexadione calcium, produced significant increases in this parameter. Overall, the results demonstrate that the evaluated vineyard management practices effectively modified canopy structure and certain parameters related to technological and enological grape quality, with cultivar-specific responses. Nevertheless, yield and sanitary status were strongly influenced by environmental conditions during the growing season. This work provides original information at the national level regarding the interaction between agronomic management, berry skin anatomy, and phenolic composition in Tannat and Syrah, contributing to a better understanding of their enological potential under the edapho-climatic conditions of southern Uruguay.

Peso al nacimiento de terneros Red Poll puros y cruzas con Angus en un sistema pastoril del norte de Uruguay

Federico Fagundez Suárez — 2026-05-29

Birth weight is the first recorded measurement of a productive animal, such as beef cattle. Its importance lies in its direct correlation with attributes crucial to beef producers, such as ease of calving and its relationship to weaning weight. In our country, numerous studies have been conducted on crossbreeding and improvement of the two main beef breeds, Hereford and Aberdeen Angus. However, there is potential for improvement through the use of other, less common beef breeds, such as Red Poll. The objective of this study is to analyze the birth weight of purebred Red Poll calves and those crossbred with Aberdeen Angus. As various studies have indicated, the lack of assistance required during calving, due to its inherent ease, is one of the many strengths of the Red Poll breed, among others. This study aimed to analyze the birth weights of purebred Red Poll (RP100%) and Angus-crossbred (RP x AA) calves in a herd in northern Uruguay. Birth weights were recorded for 30 calves, both RP100% and RP x AA. Weight was measured within the first 24 hours of life during the spring of 2025. The animals belonged to the "San Florencio" farm and ranch owned by Mr. Mariano Fernandez, located in Artigas. Subsequently, Analysis of Variance (ANOVA) was performed for birth weight, including genotype and sex as fixed effects, and the effect of birth date as a covariate.

The results showed average birth weights of 33.2 kg for RP100% and 34.2 kg for the RP x AA crossbred. Female calves, on the other hand, averaged 33.8 kg compared to 33.7 kg for male calves.

No significant differences in birth weight were found for the evaluated factors of sex, genotype, or date of birth, and it is concluded that the sample size used for this thesis was insufficient to demonstrate such differences.

Efecto del fertirriego nitrogenado en el rendimiento de maíz

Ángel Michel Arballo Bezmertny — 2026-05-28

Corn (Zea mays) is a C4 summer crop characterized by high efficiency in the use of solar radiation and a considerable capacity to produce biomass. In Uruguay, this crop has gained increasing relevance within agricultural systems, with expansions in cultivated areas and the progressive incorporation of irrigation technologies. In this context, nitrogen emerges as one of the main factors influencing yield determination. In irrigated production systems, this nutrient use efficiency becomes particularly important due to potential losses through volatilization, leaching, and denitrification. Fertigation is therefore proposed as a strategy to optimize nitrogen utilization.

The main objective of this study was to evaluate the effect of nitrogen fertigation on corn yield, considering nitrogen rate, timing of application, and water regime. The experiment was carried out at the “Dr. Mario A. Cassinoni” Experimental Station (EEMAC), located in Paysandú, during the 2024–2025 growing season. A randomized complete block design was implemented. The evaluation included three levels of nitrogen rate (100, 150, and 200 kg N ha⁻¹), two application strategies (a single application at V6 and a split application at V6+V10+V12), and two water regimes (water balance–based irrigation and excess irrigation).

The results revealed that grain yield was mainly determined by nitrogen rate and water regime. Under normal irrigation, no significant differences were observed among rate. However, under excess water conditions, the 100 kg N ha⁻¹ rate resulted in lower yields. The number of grains was the yield component most strongly correlated with productivity. Application timing did not produce difference; nevertheless, split application showed a trend toward slightly higher yields.

In summary, total nitrogen rate applied and water regime represented the main factors determining yield, while split application can be considered an adjustment tool in irrigated corn production.

Ecotoxicological Footprint Analysis of Rice Cropping Rotations with Different Levels of Intensification

Natalia Pamela Jorajuría Noya — 2026-05-27

Uruguay, with 147,031 ha allocated to rice production, accounts for approximately 2% of global rice trade, with an average yield of 9,336 kg ha⁻¹. Rice cultivation has historically rotated with pastures, integrating rice–livestock production systems since the 1920s. Recent agricultural expansion has incorporated other crops into the rotation, such as soybean and sorghum, and has increased the frequency of rice cultivation, resulting in more consecutive years of rice and fewer years of pasture return. The Uruguayan National Institute for Agricultural Research (INIA) has conducted a long-term experiment (LTE) since 2012 to evaluate different intensification technologies in rice production systems. Assessments of changes in pesticide use in Uruguayan rice production using the ecotoxicological footprint (EF) indicated that the highest contamination risk was associated with insecticides. This study characterized the agronomic and environmental performance of the LTE using a Life Cycle Assessment (LCA) approach for the period 2012–2019, analyzing six rice-based rotations with different levels of intensification by modifying summer crops and the length of the pasture phase. The EF was estimated using the USEtox model and a modified level-1 fugacity model. Both assessment methodologies allowed discrimination among rotations. The highest impacts were observed in rotations that included rainfed crops, such as soybean and sorghum (R2, R5, and R6), whereas lower impacts were found in rotations without soybean and sorghum (R1, R3, and R4). Rotations with the highest EROI were R4 and R5, while R1, R3, and R6 showed lower EROI values, and R2 exhibited an intermediate value. Overall, R4 emerged as the most sustainable rotation, as it combined the highest EROI with the lowest EF.

Evaluación de la capacidad de rebrote en Eucalyptus dunnii bajo diferentes tratamientos de cosecha

Facundo Nicolás Salvatierra Torres — 2026-05-27

In Uruguay, Eucalyptus dunnii Maiden is one of the main forest species used in pulp production. Its production system is based on two alternatives: conventional plantation or coppice management. The efficiency of the latter depends on the survival percentage achieved within a given period, which is conditioned by multiple biotic and abiotic factors. Therefore, with the aim of identifying silvicultural practices that optimize vegetative regeneration, the following objectives were proposed: 1) to evaluate the effect of cutting method, cutting height, and the application of chemical products (growth regulator and soil biostimulant), as well as their interactions, on the stump survival percentage of Eucalyptus dunnii at 135 days post-harvest; and 2) to analyze the effect of stump diameter and felling season as predictor variables of said survival. The study was conducted at two forest properties located near Alejandro Gallinal (Florida, Uruguay), named Cruz Roja and Mi Generala. Stump diameter and height were recorded at the time of trial establishment, immediately after harvest, while sprouting was assessed at 135 days post-harvest (4.5 months). Survival as a function of felling time was analyzed using descriptive statistics, while the effect of treatments and factors was evaluated using bootstrapping resampling techniques. Finally, a classical logistic model was used to assess the effect of stump diameter. The trials were analyzed independently due to frost events that affected sprouting, mainly at Mi Generala. Results indicated that the trial installed in February (at Cruz Roja) showed 25.6% higher sprouting than the one installed in March (at Mi Generala). At Cruz Roja, no significant differences were detected among treatments, cutting heights, chemical applications, or stump diameters; only the cutting method showed a significant effect, with higher survival recorded when using a harvester. At Mi Generala, treatments, cutting method, cutting height, and stump diameter all significantly influenced survival, with chainsaw and feller buncher performing notably well, along with higher cutting heights and larger stump diameters. It is concluded that felling season is a determining factor in the coppice regeneration of Eucalyptus dunnii, and its effect can be enhanced through appropriate selection of cutting method and height.

Utilización de drones para la estimación de biomasa en pasturas durante el verano

Gonzalo Davyt Malán — 2026-05-25

Livestock and dairy production in Uruguay are mainly based on pasture systems, where accurate estimation of forage availability is essential to optimize stocking rate, productivity, and overall system efficiency. Traditional estimation methods present limitations in spatial coverage and speed of measurement. In this context, the use of drones equipped with multispectral sensors emerges as a technological alternative to estimate biomass with greater precision and spatial representativeness.

The main objective of this study was to estimate the available biomass per paddock and the forage stock of the grazing platform during summer using a multispectral drone, and to compare its performance with a C-Dax pasture meter. Specific objectives included comparing the evolution of forage stock estimated by both methodologies, determining the degree of association between the NDVI index and biomass, and quantifying differences in biomass estimation at both paddock and grazing platform levels.

The study was conducted in a pasture-based system composed of perennial pastures and summer forages. Measurements were carried out weekly during the summer period. For drone calibration, the comparative yield method (COMPYLD) was used, establishing quadrants distributed across paddocks where visual estimations, height measurements, rising plate meter readings, and destructive cuts were performed to determine dry matter. The drone used was a DJI Phantom 4 Multispectral, operated at 60 m flight height. NDVI was calculated from the images and its relationship with field-measured biomass was analyzed. Data were processed to estimate biomass per paddock and total forage stock of the grazing platform, and results were compared with those obtained using the C-Dax pasture meter.

Results showed a significant linear relationship between NDVI and biomass, expressed in both kg DM/ha and kg FM/ha. However, differences in magnitude were observed between methodologies, with NDVI tending to overestimate biomass compared to C-Dax, particularly at the beginning of the summer period. Temporal evolution of forage stock showed similar patterns between methods, although absolute values differed.

It is concluded that the use of multispectral drones represents a valid tool for biomass estimation and forage stock monitoring at paddock and grazing platform levels. This technology provides rapid and spatially detailed information, contributing to improved decision-making in intensive pasture-based systems.

Parámetros genéticos y factores ambientales asociados al peso vivo en vacas lecheras

Johanna Bizoza Martinez — 2026-05-21

Live weight (LW) in dairy animals is a trait of strategic relevance in production systems, as it influences both farm income and costs. On the one hand, it relates to productive potential and feed efficiency; on the other, it determines maintenance requirements and conditions animal longevity and health. A detailed understanding of the magnitude of the genetic and environmental variation of LW, as well as its associated parameters, is essential for its inclusion in genetic selection and improvement programs.

The present study aimed to estimate the genetic parameters of LW in dairy cows, using productive and genealogical data processed via Bayesian mixed models implemented in the thrgibbs1f90 program from the BLUPF90 package. For this purpose, 1844 LW records corresponding to 1610 Holstein cows, with productive and genealogical information, were analyzed. The analysis was conducted using a univariate repeated measures model that included fixed effects of contemporary group (combination of herd and weighing date), lactation–age combination, and stage of lactation; and random effects of animal (additive genetic effect), permanent environmental effect, and residual error.

The model outputs allowed for the estimation of additive genetic variance (VA), permanent environmental variance (VEP), and residual variance (VR). From these, total phenotypic variance (VP), heritability (h²), and repeatability (r) were calculated for each posterior sample generated by Gibbs sampling, also obtaining the means and 90% credibility intervals (5th and 95th percentiles) for each parameter.

The results indicated that LW presented an average heritability of 0.593 (90% CI: 0.473 – 0.692) and an average repeatability of 0.778 (90% CI: 0.731 – 0.817). These values reflect that a large part of the phenotypic variation in LW is due to additive genetic variation, and that measurements are consistent for the same animal over time. Likewise, it was observed that the environmental effects included in the model had a significant influence on LW, particularly the contemporary group, lactation–age, and stage of lactation.

Overall, these results suggest that LW is a highly heritable and repeatable trait, with high potential for response to genetic selection. Its inclusion in breeding programs, along with the control of the identified environmental effects, could contribute to optimizing productive and economic efficiency in dairy systems, favoring the sustainability and competitiveness of the activity.

Análisis de la calidad comercial de cebada cervecera en condiciones de producción

Tomás Sobredo Toscano — 2026-05-21

Barley (Hordeum vulgare L.) is a key crop in Uruguay, ranking fourth in sown area and standing out in winter production. It is mainly concentrated in the western and central regions of the country. Its main uses are animal feed, malt production, and human consumption; in Uruguay, more than 90% is exported as malt. Its production is commercialized through contracts with malting companies, where strict quality requirements are established, which are essential for a proper malting process. In this context, the present study focuses on analyzing the effect of the environment on commercial quality parameters in malting barley varieties, particularly the impact of precipitation and temperature during grain filling on Falling Number and grain size. First, a phenological model was fitted using the INIA–INASE database. Five malting barley varieties (INIA Arrayán, INIA Osiris, Fana, Danielle, and Nahara) were considered, using records of sowing date, flowering, and physiological maturity. From these data, the variables days to flowering and days to physiological maturity were generated and modeled using linear mixed models, considering variety, sowing date, and growing season as random effects. This procedure allowed the generation of diagnostic plots to compare observed and predicted values, as well as to analyze the distribution of residuals. To apply the fitted models, a database provided by the company MOSA was also used, corresponding to commercial malting barley fields, which enabled the prediction of days to flowering and physiological maturity. To ensure spatial representativeness, fields located within the range defined by the La Estanzuela and EEMAC locations, which were used for model fitting, were selected. Based on the phenological models, the dates of flowering, physiological maturity, and harvest (considered ten days after maturity) were reconstructed. The grain filling period was subdivided into three phases (p1, p2, and p3) to characterize critical stages in quality determination. Climatic data were obtained from the NASA POWER database, considering daily mean temperature and corrected total precipitation, and accumulated values and averages were calculated for the intervals flowering–p1, p1–p2, p2–physiological maturity, and maturity–harvest. Finally, varietal, spatial, phenological, and climatic data were integrated into an expanded database, which was used in statistical analyses to evaluate the influence of environmental conditions on crop performance. The results showed a good model fit and calibration, with high agreement between observed and predicted values, supporting its reliability. This enabled its application to the malting database to analyze the relationship between environment and grain quality under real production conditions. It was found that Falling Number is particularly sensitive during the first third of grain filling, influenced by precipitation and temperature, while grain size is significantly related to temperature toward the end of grain filling and prior to harvest. Additionally, an effect of geographic location on both attributes was observed. In summary, the integration of phenological, climatic, and varietal data provides useful evidence to reduce rejection risks and guide management decisions at the production level.

Sistema antioxidante en la carne bovina de diferentes sistemas de producción

Magdalena Clavijo Larrañaga — 2026-05-20

In Uruguay, beef production is of great economic importance. Production systems range from exclusive use of pastures, pastoral systems with supplementation, confinement and use of concentrates, generating meats with different attributes of nutritional interest. Meat is a complete food in the human diet and of high nutritional quality, due to its high biological value proteins, vitamins, fatty acids and essential minerals of high bioavailability, highlighting heme iron. These can vary with the production system and the post mortem maturation, affecting the quality of the meat. Muscle glycogen, in relation to the stability of iron and changes in myoglobin, would impact the color through maturation. The objective of the work was to study the physicochemical and nutritional components and their changes in long maturation process of beef, from pastoral and feedlot systems, in two types of muscles and their relationship between them as biomarkers of the defense potential of the meat during processing. Meat samples from 30 Aberdeen Angus steers were analyzed, 15 animals were raised and finished in a pastoral system and 15 were finished in a feedlot system. After slaughter, 36 hours post mortem, the cuts of the Longissimus dorsi (LD) and Semimembranosus (SM) muscles were extracted. One portion was frozen without maturing and the other was matured for 60 days in vacuum. The following parameters were measured and determined: pH, color, dry matter, iron, Heme iron, Zinc, Copper, Manganese and glycogen. The data were evaluated using an ANOVA GLM and if there were significant differences, a Tukey-Kramer Test (p<0.05 %) was performed and by ANOVA of one way comparing maturation time for each muscle in each system. Based on the results, it can be stated that the nutritional composition and physicochemical parameters are influenced by the production system, muscle type and maturation process. The muscles presented differences in heme iron, luminosity and glycogen. The SM muscle has a higher content of heme iron and redness, lower glycogen reserves and higher final pH, with no differences at day 0, but yes at day 60. In relation to the production systems, the results reflect significant differences, the feedlot system presented higher values of heme iron, iron, zinc, while Mn was higher in feedlot. In the 60-day maturation, Fe, heme iron, Mn, Zn, color and glycogen decrease in SM, in some cases associated with the pastoral system. The LD muscle was more stable in color and Fe, heme iron content, probably in relation to its lower variation in glycogen content, demonstrating a better defense potential against the oxidative process. The stability of color in long maturation processes depends on the initial Fe and glycogen content, associated with the muscle and the production system, which would be a potential quality biomarker.

Irrigation threshold selection based on water productivity in a grazed Medicago sativa pasture

Ana Laura Elhordoy Goyeche — 2026-05-20

In Uruguay, there are 2.6 million hectares of improved pastures, of which only 2.4% are under irrigation. Drought periods are becoming increasingly frequent, significantly reducing forage production an issue that is further aggravated by the low water-holding capacity of local soils. Alfalfa is expected to respond positively to irrigation, achieving high production potential compared to many other forage species; however, results have been inconsistent. There is uncertainty regarding the optimal timing of irrigation to make the best use of rainfall, either by preventing evapotranspiration limitations or allowing them within certain limits to maximize productivity. The objective of this study was to determine the most suitable irrigation management strategy for grazed alfalfa, in terms of both the amount and timing of water applied. The trial was conducted at the Southern Regional Center, Faculty of Agronomy (Progreso, Canelones), where alfalfa cv. Chaná was sown at a rate of 20 kg·ha⁻¹. The experiment included three treatments and four replications. The treatments were: rainfed (no irrigation, T0); irrigation when 30% of available water was depleted (T30); and irrigation when 65% of available water was depleted (T65). Irrigation timing was determined by a water balance approach, supported by soil moisture measurements using an FDR probe to verify irrigation thresholds. Grazing timing was based on the 8-node criterion, with a uniformity cut at 5 cm height after grazing. The significance level used was 0.05. Annual cumulative yield showed no significant differences among treatments, with an average of 23,500 ± 979 kg DM·ha⁻¹. Differences between treatments were detected during the second summer in favor of the irrigated treatments, despite it being classified as a summer with low atmospheric demand. Regarding water productivity, T0 and T65 showed significant differences compared to T30 (52–41 vs. 37 kg DM·mm⁻¹). The maximum threshold for the relationship between biomass produced and water consumed was determined to be 500 mm·year⁻¹.

Efecto de diferentes disponibilidades hídricas sobre características morfofisiológicas de Bidens pilosa

Mario Laureano Arcaus Borges — 2026-05-08

In this work, the aim was to see how Bidens pilosa responds when water availability changes, both in terms of its growth and its functioning. To do this, two experiments were carried out under controlled conditions: one where the percentage of water in the soil was modified, and another where the number of days between irrigations was varied.

In general, it was observed that when less water is available or when more time passes between irrigations, plants grow less. This was reflected in plant height, number of leaves, stem thickness, and biomass, especially in the most restrictive treatments. In some cases, the decrease was gradual, while in others it only became clear when the deficit was more severe.

It was also observed that water consumption decreased under drier conditions, showing that the plant adjusts its functioning to reduce water loss. However, this also ends up affecting other processes, such as photosynthesis.

On the other hand, SPAD values decreased as water became limited, especially towards the end of the experiment, indicating that the condition of the plant deteriorates when water stress is sustained over time.

In summary, Bidens pilosa tolerates intermediate water deficit conditions quite well, but when the deficit becomes more pronounced, both growth and plant functioning are clearly affected.

Respuesta de cinco cultivares de cebada a la interferencia temprana de raigrás (Lolium multiflorum)

Lucas Ismael Paysal Rodríguez — 2026-05-04

Weed interference is one of the main problems in winter crops. Among weeds, Lolium multiflorum is an important species because it can compete strongly with barley. The objective of this work was to evaluate the competitive interference between five barley cultivars (Hordeum vulgare) and ryegrass (Lolium multiflorum) during early growth stages. Two experiments were carried out: a germination test in Petri dishes and a competition experiment under semi-controlled conditions. The cultivars evaluated were INIA Arrayán, Fana, Danielle, Olimpia and Attika. In experiment 1, the germination percentage of barley was evaluated in the presence and absence of ryegrass. In experiment 2, HAUN index, plant height and shoot dry biomass were measured. The results showed that the presence of ryegrass did not affect barley germination. No differences between cultivars and no cultivar × ryegrass interaction were found for this variable. In the pot experiment, ryegrass interference appeared during early barley growth. In plant height, the effect was not observed at the beginning, but it became clear from 25 days after sowing, when plants grown without ryegrass were taller. Shoot dry biomass was the variable that showed the competitive effect more clearly, because it was significantly reduced in the presence of ryegrass. Differences between cultivars were also found in biomass accumulation, with Attika showing the highest values and Fana the lowest. HAUN index was only explained by time, with no significant effect of cultivar, ryegrass or their interaction. In general, under the conditions of this study, Lolium multiflorum did not affect barley germination, but it did affect early crop growth, mainly by reducing shoot dry biomass and, to a lesser extent, plant height.

Determinación de la concentración de aceites esenciales en frutos de limón ubicados en la zona interior y exterior de árboles podados y sin podar

Santiago Peña Carretto — 2026-04-30

Uruguayan citrus cultivation covers approximately 13.300 hectares and has an annual production of around 245.000 tons, of which 40% is exported. However, lemons, which account for 31% of production, are mainly used for the extraction of essential oils (69%). The concentration and composition of these compounds, located in the flavedo glands, depend on the microclimate of the tree, the ripeness of the fruit, and management practices. There is little information on the effect of pruning and the location of the fruit on the tree on the production of essential oils. The overall objective of the study was to evaluate the concentration of essential oils in lemon fruits located in the inner and outer areas of pruned and unpruned trees. The specific objectives were: determine the effect of pruning and fruit location on fruit color, peel thickness, and essential oil concentration as maturity progresses. The study was conducted in a commercial orchard of “Criollo” lemons (Citrus limon (L.) Burm. F.) located in Kiyú, San José. Sixteen trees were used, divided into two treatment groups (pruned and unpruned), and fruits from inside and outside the canopy were evaluated on three harvest dates (June, July, and August 2021). Photosynthetically active radiation (PAR), temperature, and relative humidity were recorded during Stage II and III of fruit growth, and at harvest, size, color, and essential oil content were determined using the Scott method. Statistical analysis was performed using linear models with repeated measures over time and Tukey's test (p ≤ 0.05). Pruning increased PAR radiation transmission into the canopy at the beginning of the season, but the differences decreased toward autumn due to vegetative growth. In both pruned and unpruned trees, the fruits in the interior remained greener than those on the outside and had a higher concentration of essential oils, regardless of treatment. Advancing ripeness reduced the concentration of oils, with the lowest values obtained in August. Pruning also significantly reduced the oil content. The main conclusions of the study are: (1) Criollo lemons harvested in the middle of the season (June and July) had a higher concentration of essential oils than those harvested at the end of winter (August), (2) pruning at the end of November caused a reduction in the concentration of essential oils in the fruit, and (3) fruit located in the interior of pruned and unpruned trees achieved less coloration than those on the outside and had a higher concentration of essential oils. These results highlight the importance of microclimate and management as determinants of essential oil yield in lemons and demonstrate the need to further develop management practices aimed at optimizing this high-value component.

Biología de Tupiocoris cucurbitaceus (Hemíptera: Miridae) sobre pimiento con y sin disponibilidad de presa

Diego Andrés Callero Díaz — 2026-04-29

Whiteflies, particularly Bemisia tabaci, are among the main phytosanitary constraints affecting sweet pepper crops under protected cultivation. This has promoted the search for and evaluation of natural enemies that can be incorporated into sustainable pest management strategies. In this context, predatory mirids represent a promising alternative due to their ability to prey on different pest stages while persisting on the crop. This study evaluated the biology of Tupiocoris cucurbitaceus (Hemiptera: Miridae) on sweet pepper (Capsicum annuum) under three dietary conditions: (I) sweet pepper leaf without prey, (II) sweet pepper leaf with B. tabaci nymphs, and (III) sweet pepper leaf supplemented with Ephestia kuehniella eggs as an animal-derived food source. First-instar nymphs (N1) were individually maintained under controlled conditions, and nymphal development time, survival, sex ratio of the offspring, and adult longevity were recorded. Tupiocoris cucurbitaceus was able to oviposit and complete its life cycle on sweet pepper; however, its performance was strongly influenced by diet. In the absence of prey, development time increased and survival was markedly reduced. In contrast, prey availability or supplementation with animal-derived food allowed faster development and improved biological performance. Overall, these results support the potential of T. cucurbitaceus as a biological control agent of B. tabaci in protected sweet pepper crops, highlighting the importance of prey availability and/or dietary supplementation to optimize its establishment and efficacy.

Caracterización del período de acostumbramiento de terneros destetados precozmente

Victoria Belén de Fleitas Luzardo — 2026-04-27

Early weaning in beef cattle is a commonly used tool to improve reproductive efficiency and weaning rate; when combined with dry-lot feeding of calves and the transition period to a solid diet is carefully followed will also enhance weaning weight. Use of sensorial additives could represent a strategy to stimulate feed intake and improve adaptation to the new feeding system. The objective of this work was to evaluate the effect of the inclusion of an anise based aromatizer in the total mixed ration on early weaned calves’ performance and behavior in a dry-lot feeding system. The main hypothesis was that inclusion of an aromatizer will improve adaptation to the new feed system, enhancing feed intake, weight gain, and feed conversation ratio. Thirty-two early-weaned female Hereford calves (75 ± 19 days; 85 ± 11 kg), were stratified by body weight and randomly assigned to one of two treatments: 1) total mixed ration with whole oats as a short fiber source without aromatizer (Control; n= 16), and 2) same total mixed ration with the inclusion of an anise based aromatizer (Apetenzyma 2, Norel Animal Nutrition, Madrid, España, 3 g/animal/day) (AROM, n=16). Experiment was conducted at the Unidad de Producción Intensiva de Carne (UPIC), at the Experimental Station Dr. Mario A. Cassinoni (EEMAC), in Paysandú, for 73 days. Each calf was placed in an individual pen provided with feeder, water trough, and shade; and received corresponding treatment since day one. Feed offered was adjusted every day to ensure ad-libitum intake and divided into two equal meals per day. Main variables measured were body weight (BW) every 14 days, without fasting, to estimate average daily gain (ADG, kg/d), daily dry matter intake (DMI, kgDM/d), feed conversion ratio as kg of feed needed to gain one kg of BW (FE, kgDM:kgBW), animal behavior, feed intake rate, water intake, and total tract apparent digestibility using acid insoluble ash as an internal marker. Data was analyzed as a completely randomized design, with calf as the experimental unit. Inclusion of an anise-based aromatizer decreased DMI (4.06 vs 3.76 kg DM/animal/day for Control and AROM, respectively; P=0.01) without statistical differences in ADG (1.02 kg/animal/day; P=0.745) and FE (3.97; P=0.555). Animal behavior showed specific differential responses that were observed across weeks, associated with contrasting environmental conditions; however, these did not translate into sustained improvements in productive performance. In conclusion, in early weaned calves fed in dry lot conditions, it is not necessary to incorporate a feed aromatizer in the diet to promote adaptation to the new solid diet. It is possible to ensure a appropriate performance and feeding efficiency at such a young age when gradual adaptation protocol to the new feeding system is strictly applied.

Evaluación de deriva de diferentes configuraciones de dron en la aplicación de herbicidas

Mario Santiago Costa Rijo — 2026-04-27

Drift is one of the main issues that arise in pesticide applications using drones, due to the negative consequences it generates for the environment and human health. The objective of this study is to estimate drift from different drone applicator configurations, evaluated based on adaptations of international standards, specifically ISO 22866-2005. Three different forward speeds were assessed: 7.2 km/h, 21.6 km/h, and 36 km/h. Cyproconazole was used as the tracer to measure drift. Tracer collection zones were placed at 0 m, 100 m, 150 m, and 200 m from the drone’s flight path. Droplet size was also characterized. The experiment was conducted in Colonia Gartental, Río Negro, Uruguay, using an XAG P100 Pro drone. A completely randomized design was used, where each replicate corresponded to a drone pass and its corresponding drift evaluation. All other variables were kept constant: application volume of 12 L/ha, flight height of 3 meters, and droplet size of 230 microns. At each distance, drift was collected using 10 Petri dishes spaced 2 meters apart. Additionally, at 200 m, drift collectors were placed at heights of 1, 2, 3, and 4 meters. The application speeds of 21.6 and 36 km/h produced the highest drift. Within each distance, only at 100 and 150 meters did the 36 km/h speed result in significant differences. The amount of cyproconazole on the plates was 40.8% higher at 36 km/h compared to 21.6 km/h. Within each height, significant differences were found only at 1 meter when applying at 7.2 km/h. The concentration of cyproconazole on the rods was 55 times higher at 36 km/h compared to 21.6 km/h. High forward speeds in drone applications generate greater drift.

Impacto de la inclusión de productos derivados de levadura en sustitución de la monensina sódica en la performance y la respuesta al estrés en terneros destetados precozmente alimentados a corral

Diego Aldaya Claramunt — 2026-04-24

Early weaning in beef cattle is commonly used to improve cows’ body condition score and pregnancy rate. However, at such a young age, nutritional management of post-weaned calves could be challenging given the great nutritional requirements. One way to improve pregnancy rate together with weaning weight is a dry-lot feeding system, where the inclusion of feed additives in the diet plays a key role in improving growth, feed efficiency, stress response and health. The objective of this study was to evaluate the impact of substituting sodium monensin as a feed additive with a natural yeast derived product (Celmanax™; Church & Dwight Co., Inc.; Princeton, NJ) on performance and stress response in early weaned calves in a dry-lot feeding system. Thirty-two male castrated Hereford calves, born in spring 2024, were weaned at 71 ± 10 days of age and 88 ± 12 kg body weight (BW). Calves were stratified by BW and randomly assigned to one of the two treatments: 1) total mixed ration with 17% whole grain oats as a source of fiber (TMR without long-size fiber) with the inclusion of sodium monensin (50 mg/kg) as a feed additive (MON; n = 16); and 2) the same TMR, replacing sodium monensin with a natural yeast derived product as a feed additive top dressed (7 g/animal/day) (CEL; n = 16). Calves were placed in individual semi-roofed pens equipped with a feeder and a water trough, and received dietary treatments for 73 days, including a 17-day adapting period. Feed was offered in 2 equal meals a day, adjusting the amount offered every two days to ensure ad libitum intake. Dry matter intake (DMI, kgDM/d) was measured daily as the difference between feed offered and refusals; body weight was recorded every 14 days without fasting, and feed efficiency (FE, kgDM:kgBW) was calculated based on DMI and average daily gain (ADG, kgBW). Two blood samples were taken from the jugular vein, at the beginning and at the end of the experimental period, for plasma cortisol level determination. During the same weeks, fecal samples were collected on three consecutive days to estimate total tract apparent digestibility of dry matter (DM) and organic matter (OM), using acid-insoluble ash as an internal marker. The data was analyzed in a completely randomized design. The inclusion of CEL as a substitute for MON, allowed to achieve the same DMI and ADG, reaching the same final body weight (P ≥ 0.316); and resulted in a better stress response, or better adaptation, due to a lower plasma cortisol level at day 73 (MON: 1.7238 μg/dL and CEL: 1.3225 μg/dL; P = 0.049). However, the FE achieved in MON was better (3.57 vs 3.80 CEL, P = 0.038), accompanied by greater digestibility, of both DM and OM (P < 0.0001), and lower water intake (P = 0.041). Despite this, the substitution of sodium monensin with a natural feed additive is considered feasible since the performance of calves was not affected and an apparent better stress response was achieved, even when calves were fed with a highly concentrated TMR without long size fiber in a dry-lot feeding system.

Calidad de plantines de Eucalyptus smithii en función del tamaño de tubetes y del uso de reguladores de crecimiento

Yenifer Barón Ferreira — 2026-04-23

Eucalyptus smithii has become a relevant species within the Uruguayan forestry sector, mainly as an alternative to Eucalyptus globulus, whose productivity declined following the emergence of Teratosphaeria nubilosa in 2007. In addition to its adequate silvicultural performance, it shows suitability for timber and pulp production, as well as frost tolerance. However, episodes of mortality during the early stages of the crop have been reported in recent years, without a precise diagnosis of their causes. In this context, this study evaluated strategies to improve the quality of seedlings intended for field establishment by analyzing the effect of growth regulators on root development and the influence of container type during the nursery stage. The experiment was conducted at the Saucedo nursery (Solís de Mataojo, Lavalleja, Uruguay) under a completely randomized factorial design, considering two factors: container type (three levels) and hormonal application (with and without application), with three replicates per treatment. The hormonal treatment was applied foliarly 99 days after sowing, using a solution of naphthaleneacetic acid (NAA) and aminoethoxyvinylglycine (AVG) at concentrations of 600 mg L⁻¹ and 125 mg L⁻¹, respectively. Three container types differing in design and volume were evaluated: large container (325.125 cm³), small container (30.49 cm³), and square container (172.40 cm³). Two morphological evaluations were performed: at the time of application on a subsample of seedlings from each treatment, and at 173 days after sowing, including a total of 342 seedlings. In both evaluations, root collar diameter (RCD), height (H), leaf dry weight (LDW), stem dry weight (SDW), and root dry weight (RDW) were measured, and total dry weight (TDW) and quality indices were calculated. Results showed that container size was the main factor determining seedling growth and quality, whereas the hormonal treatment mainly influenced biomass allocation among seedling organs and morphological balance. In general, larger containers promoted greater growth and biomass accumulation, while hormonal application favored a higher proportion of root development and improved quality indicators. The joint analysis of morphological variables and quality indices demonstrated that larger plant size does not necessarily imply better quality, highlighting the importance of an integrated evaluation in forest seedling production.

Resistencia de dos variedades de arroz a la chinche del tallo, Tibraca Limbativentris Stål. (Hemiptera: Pentatomidae)

Valentina Elizabeth Martínez Ortiz — 2026-04-22

Rice (Oryza sativa L.) is a strategic crop for Uruguay. Among the major pests, the rice stem bug, Tibraca limbativentris (Hemiptera: Pentatomidae), stands out; it shelters at the base of rice tillers and can affect the crop during both vegetative and reproductive stages. The aim of this study was to determine the preference and the effects of rice varieties on biological traits of T. limbativentris under controlled conditions, and to complement this information with field population monitoring. Preference (antixenosis) was evaluated through free-choice tests on four rice varieties: INIA Olimar, Gurí INTA CL, INIA Cuareim (SLI09197), and SLI09193. For this purpose, 16 plants (randomly arranged from the four varieties) were set up and four T. limbativentris females were released; their choice was recorded from 0.5 to 48 h. Biological traits (antibiosis) were assessed under laboratory conditions on INIA Cuareim (SLI09197) and SLI09193, recording the duration of each developmental stage, total developmental time, and survival capacity. Field population monitoring was conducted through monthly visits (October–March) at a commercial farm in northern Uruguay during the 2023/24 and 2024/25 growing seasons, in INIA Olimar and INIA Merín, at 10 sampling points using a 1 m² quadrat. In the preference assays, females showed higher selection for Gurí INTA CL and INIA Cuareim (SLI09197), whereas SLI09193 was the least selected material; INIA Olimar also showed low selection, suggesting non-preference. In the biological assays, performance was similar between INIA Cuareim (SLI09197) and SLI09193; survival to adulthood was low in both varieties, but even lower in SLI09193. Total developmental time was longer in INIA Cuareim (SLI09197) than in SLI09193 (x̄ = 6.35 days; p = 0.0001). In field evaluations, population abundance was strongly conditioned by phenological stage and interannual variation, with low presence during the vegetative stage. During the reproductive phase—especially in the 2023/24 season—higher pest presence and differences between varieties were observed, with higher population levels in INIA Merín than in INIA Olimar (ratio = 2.29; p = 0.0003). This study integrates evidence on behavior, biological performance, and field dynamics, showing that T. limbativentris responses depend on plant material and crop timing. The results reinforce the importance of monitoring during reproductive windows and provide inputs to discuss the use of less attractive and/or less suitable varieties as hosts within integrated pest management strategies supported by local evidence. These results constitute a baseline and may guide future evaluations of varietal resistance and adjustments to management strategies and intervention thresholds.

Caracterización de propiedades mecánicas y físicas de Eucalyptus grandis Hill ex Maiden mediante técnicas destructivas y no destructivas

Joaquín Corbo Iturburu — 2026-04-22

In Uruguay, the growth of the forestry sector and the increasing interest in the structural use of wood justify the generation of local information to support the technological valorization and classification of Eucalyptus grandis. Within this context, the general objective of this study was to characterize the physical and mechanical properties of wood obtained from 9-, 12-, and 15-year-old plantations, to evaluate the influence of age and radial position within the stem, and to estimate the modulus of elasticity using non-destructive techniques, analyzing its correlation with a destructive reference method. The study was carried out using specimens obtained from sawn timber, on which non-destructive tests were performed using Fakopp and Sylvatest instruments, as well as destructive static bending tests under a three-point loading configuration using a universal testing machine. Additionally, attributes such as moisture content and wood density were determined following recognized procedures and technical standards for physical–mechanical characterization. Data analysis included descriptive statistics, correlation analysis between methods and wood properties, principal component analysis, and classification models based on decision trees. The results showed increases in density, modulus of elasticity, and modulus of rupture with increasing age and from pith to bark. The mean values of modulus of elasticity were 11,166.21 MPa for 9 years, 13,611.39 MPa for 12 years, and 11,313.57 MPa for 15 years. Likewise, the mean values of modulus of rupture were 71.197 MPa, 74.353 MPa, and 76.296 MPa for the respective ages. Significant correlations were identified between the modulus of elasticity values obtained through non-destructive methods and those determined by destructive testing, confirming consistent trends between both approaches. Furthermore, it was confirmed that age and radial position significantly influenced the evaluated properties, and that non-destructive techniques constitute a reliable tool for inferring the mechanical behavior of wood. These techniques provide relevant information for the classification, valorization, and structural use of Eucalyptus grandiswithin the national productive and technological context, while also reducing time and costs associated with destructive testing. However, the results also highlight the need to incorporate additional variables in order to achieve a more accurate estimation of the modulus of elasticity.

Generación de una base de datos de la raza Angus para la generación de una app de condición corporal

Mauricio Grieco Machiñena — 2026-04-10

Cattle farming is one of Uruguay's main productive sectors, and its efficiency depends largely on the reproductive performance of breeding herds. In this context, body condition score (BCS) is a fundamental tool for assessing the nutritional status of cows and predicting their reproductive response, especially in the postpartum period. However, visual estimation of BCS is subjective, as it depends on the evaluator's experience and the correct application of technical criteria. Within the framework of the agricultural digitalization, the development of tools based on artificial intelligence represents an opportunity to standardize and automate this type of assessment. The overall objective of this study was to generate a database of images of breeding cows correctly classified by body condition, which would serve as input for the development of an application capable of automatically estimating this indicator using artificial intelligence models. The specific objectives were to design an appropriate methodology for image capture and to build a database representative of the different body condition scores. The study was carried out in October 2025 at the “Las Nazarenas” farm, located in the departament of Flores, Uruguay. The study involved 140 multiparous cows of the Aberdeen Angus and Red Angus breeds, all with calves at foot. Each animal was photographed individually from a standardized rear view and classified by body condition through visual assessment at the time of fieldwork by three evaluators. Subsequently, the images were reclassified in an independent desktop instance. The data obtained were analyzed using descriptive statistics, analysis of variance (ANOVA), simple linear regression models, and Pearson correlation coefficients, using SAS software (V9.4). The average body condition score determined in the field was 3.42 ± 0.66, with a range between 2 and 5.5, wich showed adequate variability for the generation of the database. The regression models were highly significant (p < 0.0001) for all three evaluators, with coefficients of determination of 0.83, 0.72, and 0.67. The analysis of variance showed significant differences between observers (F = 10.66; p < 0.0001), although the evaluator effect explained only 4.9% of the total variability observed. Likewise, the correlations between the field assessment and the assessment based on images were high (r = 0.82–0.91), indicating a strong association between the two measurements. It is concluded that the estimation of body condition using images is a technically viable and statistically validated tool. The database generated represents a significant contribution to the development of artificial intelligence-based applications, with the potential to improve objectivity, repeatability, and efficiency in the assessment of body condition in livestock breeding systems.

Eficiencia alimenticia de novillos Wagyu y cruza F1 Wagyu x Holando en confinamiento

Juan Manuel Strauch Turturiello — 2026-04-10

In feedlot production systems, feed utilization efficiency is a key factor determining the economic sustainability of the operation, particularly in systems based on high-value breeds such as Wagyu. In this context, crosses between Wagyu and dairy genotypes such as Holstein may represent a promising alternative by combining the greater feed intake capacity and growth efficiency of dairy breeds with the characteristic meat quality of Wagyu. The objective of this study was to evaluate organic matter intake and digestibility, residual feed intake (RFI), feed conversion efficiency, and feeding and postural behaviour in purebred Wagyu (W) and F1 Wagyu x Holstein crossbred (WH) steers under feedlot conditions, as well as to analyze the association among these variables in order to contribute to the understanding of the biological basis of individual feed efficiency. The study was conducted on a commercial farm located in Soriano, Uruguay, where 16 steers (W, n = 8; WH, n = 8) were evaluated for 56 days under uniform management and feeding conditions. During the experimental period, productive performance variables, individual feed intake using electronic feeders, diet digestibility and animal behaviour were recorded. WH steers showed greater body weight, higher average daily gain, and greater dry matter intake than W. From a behavioral perspective, WH spent less time at the feeder but exhibited higher feeding rates and greater intake per visit, as well as longer resting times. In contrast, no differences between genotypes were observed for residual feed intake. Overall, the results indicate greater productive performance of WH under feedlot conditions, however, factors associated with management and feed supply during the experimental period may have limited the expression of voluntary intake and the ability of RFI to discriminate differences in feed efficiency between genotypes.

Supervivencia estival de macollos de gramíneas C3 en sotobosque forestal

Luciano Maneiro Murrú — 2026-04-09

Given the increasingly intense, hot, and dry summers in subtropical regions such as Uruguay, where the persistence of certain winter grasses may be jeopardized, it is crucial to design effective strategies that enhance their survival within livestock production systems, particularly those based on pastures. We hypothesize that the conditions created by a silvopastoral system (SPS) reduce tiller mortality in perennial C3 grasses that are better adapted to shaded environments. This study assessed the tiller dynamics of two perennial C3 grasses with contrasting shade tolerance (Dactylis glomerata: tolerant; Lolium arundinaceum: moderately tolerant) and one biennial C3 grass typical of humid environments (Holcus lanatus), under full sun and SPS with tree rows-oriented north–south (N–S) and east–west (E–W). Eucalyptus grandis significantly altered the understory microclimate, reducing photosynthetically active radiation (PAR) and moderating both air and soil temperatures. The N–S orientation allowed greater penetration of radiation into the understory compared to E–W. Tree-based systems lowered summer soil temperatures by approximately 3°C relative to the control treatment. Soil moisture was higher under E–W orientation during the warm months. D. glomerata emerged as the species with the highest tiller density in the understory at the end of the first summer, particularly under N–S orientation, due to greater survival and continuous establishment compared with L. arundinaceum and H. lanatus. In contrast, L. arundinaceum exhibited reduced survival and tiller emergence under trees, despite maintaining high density under full sun. Its tiller density and survival were strongly associated with PAR and soil temperature, while soil moisture exerted little influence. H. lanatus, meanwhile, suffered high mortality across all treatments, with complete tiller disappearance in the understory by the end of summer. Overall, the findings suggest that in subtropical climates, silvopastoral systems can enhance the persistence of D. glomerata during the warm season, ensuring its survival and population stability.

Efecto de la pulverización con fungicida sobre el control de la roya estriada y la presencia de residuos en el grano de trigo

Ivana Sofía Jolochín Cerrudo — 2026-04-09

Chemical control is the primary management strategy for stripe rust (SR) in wheat, and its effectiveness largely depends on application timing and spray quality. Under highly conducive conditions, multiple applications during the crop cycle may be required, increasing the risk of fungicide residues in grain. The objective of this thesis was to evaluate the effect of droplet size on SR control efficiency using a fungicide mixture and to assess the risk of residue occurrence in wheat grain as influenced by application timing. Two experiments were conducted using a cultivar susceptible to SR. In Experiment 1, a fungicide mixture (fluxapyroxad, epoxiconazole, and pyraclostrobin) was applied using two droplet sizes (coarse and fine) at three application timings: critical threshold (Ct), 15 days after Ct, and GS49. Disease control and grain yield were evaluated. In Experiment 2, the same mixture was applied with both droplet sizes at different crop growth stages, simulating scenarios with a high risk of residue occurrence in grain. Stripe rust was first detected at GS41 and reached a maximum severity of 26%. Although differences in disease levels were observed among treatments, control efficiency and yield showed limited variation. The application performed at Ct did not achieve the expected level of control, likely due to the spatial heterogeneity of the epidemic and the environmental conditions following application. These findings highlight the importance of continuous monitoring and of adjusting fungicide decisions according to epidemic dynamics and weather forecasts. In Experiment 2, droplet size did not significantly influence fungicide residue concentrations in grain. Applications performed at advanced growth stages and multiple applications that did not comply with the pre-harvest interval exceeded the maximum residue limits established by international regulatory bodies. Overall, the results emphasize the importance of timing fungicide applications based on pathogen detection and predicted conducive environmental conditions, prioritising the use of coarse droplets to minimise spray drift and strictly adhering to label-specified pre-harvest intervals.

Evaluación del contenido de nitrógeno durante el crecimiento del cultivo de cebolla mediante sensores para determinaciones rápidas

Tomas Betancor Farías — 2026-04-07

Onion (Allium cepa L.) is one of the main vegetable crops in Uruguay, and its yield depends largely on proper nitrogen (N) management. However, traditional nutritional diagnostic methods, such as laboratory analysis, are limited by their cost and response time. In this context, this final degree project aimed to generate knowledge to improve nutritional management in onion crops, enhancing production and reducing the risk of environmental impact. The use of a rapid method for determining nitrate content in sap using the LAQUAtwin sensor was evaluated, correlating its results with those obtained through laboratory analysis, while also studying the effect of different nitrogen doses on physiological and yield variables in two onion varieties (Armonía CRS and Pantanoso del Sauce CRS).

The experiment was conducted at the Centro Regional Sur (Progreso, Canelones) during the 2022 growing season, under a factorial design with two cultivars and three nitrogen fertilization levels. Physiological indicators such as leaf area index (LAI), bulbification index, total and marketable yield, and nitrate concentration in different plant tissues (leaf, stem, bulb, and root) were evaluated. In addition, nitrogen use efficiency and the relationship between sensor and laboratory measurements were analyzed.

Results showed positive and significant correlations between the rapid sap test and laboratory nitrogen determinations, demonstrating that the LAQUAtwin sensor is a useful tool for nitrogen diagnosis in onion crops. Nitrogen doses affected physiological variables and yield, with the best responses observed at intermediate doses. The cultivar Armonía showed higher nitrogen use efficiency and better physiological performance than Pantanoso. This approach could be extended to other horticultural crops in intensive production systems, contributing to more efficient and sustainable agriculture.

Evaluación de resistencia en una colección núcleo de parientes silvestres de Solanum tuberosum L. A Alternaria SPP. y caracterización de los aislados utilizados

Camila Belén Couture Santos — 2026-04-07

Potato (Solanum tuberosum L.) is seriously affected by early blight, a disease caused by a complex of Alternaria species. This leads to a high dependency on synthetic chemical fungicides, which promotes the emergence of resistant pathogens. Therefore, identifying sources of genetic resistance in wild potato relatives emerges as a sustainable alternative to address this issue. The objective of this work was to evaluate early blight resistance in a collection of wild accessions from Uruguay, primarily composed of Solanum commersonii and Solanum malmeanum. Additionally, the study aimed to characterize the Alternaria spp. isolates used in the trials physiologically, morphologically, and molecularly. Assays were performed on detached leaves from the core collection of wild relatives using three Alternaria spp. isolates. Morphological characterization was based on evaluating growth and sporulation in two culture media, while physiological characterization assessed two different incubation methods. Molecular characterization was performed through DNA extraction and analysis of gene regions. For the resistance assays, detached leaves were inoculated with spore suspensions of 2x10⁴ esporas.mL^-1. Molecular identification revealed that isolates 2B and 12 are Alternaria alternata, while isolate 10 could not be confirmed at the species level. Regarding morphology and physiology, the isolates showed better growth and sporulation on CA medium under a 12-hour photoperiod and near-UV light, evidencing the high phenotypic plasticity of the genus. Finally, regarding the resistance trials, the absence of infection symptoms in most accessions highlights the low aggressiveness of A. alternata.

Estrategias de manejo químico para el control de Pyrenophora teres f. teres en cebada

Malena Alemany Passadore — 2026-04-07

Net blotch (NB), caused by Pyrenophora teres f. teres (Ptt), is one of the main foliar diseases of barley, affecting both grain quality and yield. In this context, the general objective of this study was to evaluate chemical management strategies for NB control, considering the use of different seed-treatment fungicides, foliar fungicides and biostimulants products, as well as the timing of application and their interaction with cultivars exhibiting contrasting sanitary behavior against NB. To this end, two field trials were conducted during the 2024 growing season at the “Dr. Mario A. Cassinoni” Experimental Station of the Faculty of Agronomy, Paysandú department. The first trial analyzed the interaction between seed treatment and the timing of foliar fungicide mixture applications in two cultivars with contrasting responses to Ptt. In the second trial, the relationship between seed-treatment fungicides and different timings of foliar agrochemical mixtures was evaluated on a Ptt-susceptible cultivar. Epidemiological and productive variables were recorded, such as disease severity, area under the disease progress curve (AUDPC), grain yield, and thousand-kernel weight (TKW). The results showed that the evaluated chemical strategies significantly reduced disease severity, expressed as AUDPC, compared to the untreated infected control. In particular, treatments combining seed treatment with strategically timed foliar applications achieved the highest NB control efficiency. However, in several cases, the reduction in disease severity did not translate into significant differences in grain yield. Regarding TKW, significant interactions were observed between variety and fungicide treatment, indicating differential responses depending on the sanitary behaviour of the genetic material. Integrated management combining genetic resistance, seed treatment, and strategically foliar applications, proved to be an effective strategy for reducing NB severity. Nevertheless, under certain environmental conditions, a reduction in disease progress does not necessarily resulted in significant yield increases. These findings highlight the importance of considering infection timing, cultivar susceptibility, and climatic conditions when designing chemical control strategies, as well as the need for further research to better understand the relationship between epidemiological control and its impact on productivity.

Evaluación del dron como tecnología de aplicación de herbicidas para control de malezas en implantación de pasturas mezcla

Felipe Bonino Fernández — 2026-04-06

Weed control represents one of the main challenges in modern agricultural systems due to its influence on crop yield and production efficiency. For this reason, proper weed management within production systems is essential, employing different control methods and approaches in order to preserve productivity in both the short and long term. In this context, the incorporation of precision technological tools, such as the use of drones for herbicide application, emerges as a viable and innovative alternative to optimize resources, enable applications under certain unfavorable conditions, and reduce environmental impact. The objective of this study was to evaluate different drone application configurations for weed control in establishing pastures. To achieve this, two experiments were conducted, assessing the level of weed control, droplet impact density on the target surface, and recovery rate. The trials were carried out at the Estación Experimental Mario A. Cassinoni (EEMAC) of the Facultad de Agronomía between June and September 2025 using a DJI Agras T40 drone. In the first experiment, two treatments were evaluated corresponding to the application volumes of 10 L/ha and 20 L/ha, where recovery rate, droplet population parameters, and control efficiency were assessed. The second experiment consisted of four treatments resulting from the combination of the same application volumes with droplet sizes of 350 µm and 500 µm, determining droplet population parameters and the percentage of weed control. Overall, the results showed that neither application volume nor droplet size had a direct significant impact on the control efficiency of the weeds present. However, when modifying the configuration of these parameters, trends toward higher levels of control were observed depending on the weed species, plant size, and the environmental conditions during and after application. Droplet impact density did not show significant differences between treatments in Experiment 1, whereas in the second experiment an interaction between the evaluated parameters was detected. The highest number of droplets per unit area was achieved with the combination of 20 L/ha and medium droplet size (350 µm). Regarding the recovery rate evaluated in Experiment 1, a greater amount of recovered product was observed in the 10 L/ha treatment, mainly associated with the wind factor. Drone technology represents an innovative approach for pesticide applications; however, further studies on configuration parameters are required to ensure the responsible and effective use of this technology.

Relación entre condición corporal y la eficiencia reproductiva en vacas de cría de diferentes genotipos

Wilson Federico Da Silva González — 2026-04-06

Reproductive efficiency is a key factor in the productivity of cattle breeding systems, particularly under extensive conditions where forage availability is variable and affects reproductive performance. Body condition score is among the most widely used indicators, as it is closely associated with pregnancy probability and calving interval. In this context, crossbreeding can contribute to improved productive and reproductive efficiency through heterosis. This study aimed to analyze the relationship between body condition score at calving and reproductive efficiency, measured by calving interval and calving percentage, in beef cows of different genotypes managed on native pasture in Uruguay. Records from the breeding herd of the Bernardo Rosengurtt Experimental Station (EEBR) of the Faculty of Agronomy, University of the Republic, covering the period 2006–2017, were used. Cows of the Angus (AA), Hereford (HH), and their reciprocal crosses (AH and HA) genotypes were analyzed. The variables considered were body condition score at calving (BCC), first calving interval (FCI1), average calving interval (FCI), and calving percentage. Effects evaluated included forage availability, category, cow and bull genotype, and month and year of calving. Data were analyzed using non-parametric tests and tests of independence with R software (version 4.5.1). Significant differences in body condition score at calving were observed in association with forage availability, category, cow genotype, and month and year of calving (p < 0.001). Crossbreeds (AH and HA) had higher mean BCC scores (3.84–3.85) than purebreds (3.67–3.71), with less internal variability. In the first calving interval, no significant differences were observed according to the cow's genotype, although differences were observed according to the bull's genotype, with HA having the shortest average (460 days) and AA the longest (509 days). In the average calving interval, crossbred genotypes showed shorter values (432–434 days) compared to purebred genotypes (460–461 days). Calving percentages were high and varied among categories, with values ranging from 86.4% to 94.7% in heifers and from 85.9% to 91.3% in cows, showing a favorable trend toward crossbred genotypes. Body condition at calving is a relevant variable in the analysis of the herd's reproductive efficiency, evaluated through calving percentage and calving interval. The crossbred genotypes (Hereford × Angus and Angus × Hereford) showed a trend toward greater reproductive efficiency, associated with slightly higher body condition scores at calving and a lower body condition score required to achieve the same calving percentage, compared to the purebred genotypes. Calving intervals did not differ significantly between genotypes, being primarily associated with other environmental and management factors. These findings suggest that crossbreeding could contribute to improved reproductive regularity and efficiency in extensive grazing systems on native pastures, which should be evaluated in future studies with greater control of environmental and management variables.

Evaluación de un sistema de autopesaje en vacas de cría sobre campo natural

Victoria María Carrau García — 2026-03-27

In this study, the relationship between liveweight (LW) measured using traditional static weigh (SW) system and a automatic/self-weighing system, Optiweigh, in 24 breeding cows (Angus, Hereford, and F1 crossbred) grazing natural grassland at the Bernardo Rosengurtt Experimental Station, located west of the city of Melo. Over 10 weeks, cattle were weighed approximately every four weeks using the SW system, while automatic/self-weighing (OW) system continuously monitored LW in the paddock. The relationship between weights obtained from SW and OW was analyzed using correlation analysis, showing significant (p < 0.05) and moderate to high correlation coefficients (0.74–0.96). Average liveweight varied according to the method used, with OW values being higher than SW in two of the three evaluation dates (470 kg vs. 446 kg, respectively). In conclusion, although similarities were observed between both methods, the OW system does not currently replace the SW system. However, this study should be complemented with further research controlling additional environmental factors (paddock size, scale location, animal competition) and including a greater number of records for analysis.

Inoculación de semillas de cebolla con microorganismos benéficos

María Gabriela Barreto Bon — 2026-03-25

In Uruguay, onion production is of great economic importance; however, there are still fewer research-based tools available for integrated disease management compared to those developed for protected horticultural crops. The country’s soils are characterized by high fertility and a broad diversity of microorganisms. Nevertheless, the intensive use of horticultural production systems leads to their progressive degradation, turning them into environments favorable for the development of various pathogens. National production is mainly based on cultivars developed by INIA and the Facultad de Agronomía, and most of the commercialized seed is nationally produced and certified. In this context, offering seed inoculated with beneficial microorganisms would allow the replacement of chemical seed treatments, taking advantage of biological mechanisms to contribute to a more sustainable integrated management approach.

Seed inoculation with beneficial microorganisms represents a tool with the potential to optimize resource use and promote improved early plant growth; however, its application in horticulture remains uncommon. In this study, the effect of onion seed inoculation with Trichoderma afroharzianum strain TR48 and Clonostachys rhizophaga strain P43, applied separately, was evaluated. The cultivars Vicky F1 (Italy) and Pantanoso del Sauce CRS (Uruguay) were used. The microorganisms were grown on PDA medium plates, from which spores were harvested and subsequently encapsulated with additives to enhance their viability. Viability was assessed with and without additives at 0, 7, and 14 days after inoculation under two storage conditions: room temperature and refrigeration at 4–5 °C.

In dual culture assays, Clonostachys P43 showed a significant effect in controlling Botrytis (43.3 cm² of pathogen area in the presence of P43 compared to 55.9 cm² in the control), although it did not show an effect against Fusarium. In contrast, Trichoderma TR48 exhibited greater control capacity against both pathogens (20.9 and 25.1 cm² of Botrytis and Fusarium area, respectively, compared to 55.9 and 35.9 cm² in the controls), which was associated with its higher in vitro growth rate. In a bioassay conducted in sand artificially infested with Fusarium, both strains had a positive effect on seedling weight when using the low-virulence strain UR01; however, they were not effective against the more virulent strain NL93816 under the methodology applied. The average seedling weight in the presence of NL93816 was 0.030 g, whereas with inoculation it reached approximately 0.076 g per seedling.

Both strains maintained their viability on PDA up to 7 days after inoculation (17 cm² for TR48 and 11 cm² for P43), decreasing at 14 days (12.5 cm² and 8 cm², respectively) in the Vicky cultivar; a similar pattern was observed in Pantanoso and under both storage temperatures. The use of additives resulted in high levels of in vitro contamination, indicating the need for methodological adjustments. Under field conditions, at 60 and 90 days after sowing, inoculated seeds produced plants with greater weight and leaf area, although with smaller stem diameter. Natural disease incidence was low and no significant differences were detected. The use of beneficial microorganisms represents a promising alternative to strengthen crop health and sustainability.

Producción primaria y sobrevivencia estival de la mezcla forrajera Festuca arundinacea, Trifolium repens, Lotus corniculatus en su primer año bajo combinaciones de frecuencia e intensidad de pastoreo contrastantes

Sofía María Vellozo Peña — 2026-03-24

In Uruguay, animal production is largely based on pasture-based systems, where grazing management plays a key role in determining pasture productivity and persistence. The objective was to evaluate the effect of contrasting combinations of grazing frequency and intensity on forage production, botanical composition, and tiller survival of a forage mixture composed of Festuca arundinacea, Trifolium repens, and Lotus corniculatus during its first year of establishment. The experiment was conducted at the Estación Experimental “Dr. Mario A. Cassinoni” (Paysandú, Uruguay) between August 2022 and May 2023, using a randomised complete block design with a 2 × 2 factorial arrangement, combining two defoliation frequencies (two and four leaves on Festuca arundinacea) and two grazing intensities (30% and 70% residual forage), with four replicates. Results showed that during the first evaluation period (winter–spring), the lower defoliation frequency (four leaves) significantly enhanced pasture production and growth rate, regardless of grazing intensity. However, in subsequent periods, differences among treatments were reduced, mainly due to the pronounced water deficit recorded during spring and summer, which limited the potential growth of the pasture. Grazing intensity had a minor effect on forage production, with differences observed primarily in residual forage during the summer–autumn period. Botanical composition exhibited marked seasonal variation, with a greater contribution of legumes in summer, associated with the summer growth pattern of Lotus corniculatus, and a predominance of Festuca arundinacea in autumn. Species responses to grazing management were differential: tall fescue was favoured by more frequent grazing, white clover by less frequent and more intense defoliation, and lotus by low grazing intensity. Tiller density declined significantly toward autumn, with no differences among treatments. In conclusion, lower grazing frequency and intensity favoured the initial productivity of the forage mixture; however, management effects were strongly conditioned by environmental factors. These results highlight the importance of adjusting grazing strategies according to climatic conditions to improve the productivity and persistence of perennial pastures in Uruguayan grazing systems.

Caracterización de yemas de Festuca arundinacea y Lolium perenne bajo diferentes niveles de estrés hídrico en verano y otoño en un ambiente limitante para el crecimiento

Sofía Blanco Chacón — 2026-03-23

Winter perennial grasses play a key role in Uruguayan pasture systems due to their contribution to productive sustainability, with regeneration from axillary buds being a central component of their persistence under water stress. This study evaluated the number and physiological state of buds in tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne) under different levels of water deficit during the summer and autumn of 2024–2025 in the northern coastal region of the country.

A field experiment was conducted at the Experimental Station of the Faculty of Agronomy (Salto), with treatments of irrigation and moderate and severe water deficit. The total number of buds per tiller was quantified, and their physiological state (active, dormant, and dead) was determined using tetrazolium and Evans Blue staining techniques. To analyze the collected data, general linear and generalized linear mixed models were fitted with environmental covariates associated with water and heat stress, and ANOVA tests and mean comparison tests were implemented.

The results showed that the total number and physiological state of the buds were determined by the interaction between species, season, water treatment, and time of evaluation. Tall fescue (Festuca arundinacea) presented a more abundant and stable bud bank, especially during autumn, while perennial ryegrass (Lolium perenne) showed greater sensitivity to summer stress, evidenced mainly by an increase in the proportion of dormant buds. Water deficit was primarily associated with increased dormancy, while supraoptimal temperatures favored bud activation, without marked increases in mortality.

The study concludes that the persistence of these perennial grasses in environments with water deficit and heat stress depends more on their ability to regulate the physiological state of their bud bank than on its size. Tall fescue (Festuca arundinacea) exhibits intrinsic morphophysiological strategies that confer greater stability and recovery capacity under stress, while perennial ryegrass (Lolium perenne) shows less persistence under these conditions. These results confirm the hypotheses and highlight the bud bank as a key indicator for the management and selection of forage species in pasture systems subjected to restrictive climatic conditions.

Efecto de la edad del fruto en la intensidad de brotación y floración del limón Eureka

Sofía Belén Juncal Martínez — 2026-03-17

Citriculture is the main horticultural production in Uruguay, with lemon production accounting for 31 % of the national output. Unlike other citrus species, the lemon tree generates reproductive shoots in all its sprouting flushes, which allows for the coexistence of fruits at various developmental stages and facilitates a summer harvest in addition to the winter one. Floral induction in Citrus is regulated by a complex interaction of endogenous and exogenous signals. Endogenously, the fruit exerts a significant inhibitory effect, primarily associated with gibberellins, which repress the expression of genes linked to floral induction and differentiation. Furthermore, fruit presence in the brunch reduces shoot sprouting, thereby restricting the formation of new buds. The main exogenous factors promoting this process are low temperatures and water stress. Given the reflorescent characteristic of the lemon tree, it is essential to elucidate the influence of the fruit’s developmental stage on the regulation of flowering intensity during both spring and summer-autumn sprouting. The objective of this study was to determine the effect of the fruit developmental stage of the 'Eureka' lemon tree on spring and summer-autumn sprouting and subsequent flowering. Specifically, the influence of winter-harvest and summer-harvest fruit was evaluated on these flushing events, as well as the effect of bud position (apical vs lateral). The experiment was conducted in a commercial orchard in San José, using one branch as the experimental unit with 30 replicates per treatment. Four treatments were established: (SF) branches without fruit; (CFi) branches with fruit in Stage III during winter (winter harvest); (CFv) branches with fruit in Stage II in winter and Stage III in summer (summer harvest); and (CFv-R) branches with fruit in Stage II in winter and without fruit in summer. Sprouting and flowering (number of shoots and nodes) were evaluated in spring and summer-autumn, and shoot type and bud position on the branch were identified. Data were analysed using generalised linear mixed models. Results demonstrate that SF branches exhibited the highest sprouting and flowering intensity. Fruit presence significantly reduced both variables. The CFi treatment (fruit in Stage III during the inductive period) significantly reduced flowering and the proportion of reproductive shoots, while simultaneously increasing the proportion of vegetative shoots. Conversely, CFv and CFv-R treatments exerted a more marked inhibition on shoot sprouting; however, considering the flushed nodes, an intermediate proportion of reproductive shoots was recorded. Summer-autumn flushing was minimal; fruit presence almost completely suppressed it, with no shoots in CFv and CFv-R. Only SF displayed flowering, suggesting a persistent inhibitory effect of winter-harvest fruit. In summary, fruit presence has a marked inhibitory effect on sprouting and flowering. This effect seems to be conditioned by the fruit’s developmental stage: fruits in Stage III during the winter induction period were associated with the highest flowering suppression. Conversely, summer-harvest fruits (in Stage II in winter) inhibited spring sprouting more strongly than winter-harvest fruits (in Stage III in winter). No significant effect of bud position was found on spring sprouting and flowering.

Efecto del uso de aceites como aditivos nutricionales sobre la performance animal de novillos pastoreando sorgo forrajero durante el verano

César Francisco Echenique Valenzuela — 2026-03-16

The objective of this study was to evaluate the effect of using essential oils as a nutritional additive, together with supplementation with dried distiller’s grains (DDGS), on performance, ingestive behavior, and physiological indicators associated with heat stress in steers grazing forage sorghum during the summer. The experiment was conducted at the Mario A. Cassinoni Experimental Station, Paysandú, Uruguay, between January 16 and March 13, 2025 (56 days). Seventy-two Hereford steers with an average body weight (BW) of 285 ± 36.7 kg were blocked by BW and randomly assigned to three treatments (3 replicates per treatment; 8 animals per replicate): grazing without supplementation (Control); grazing with DDGS supplementation at 0.5% of BW; and grazing with DDGS supplementation at the same level plus a mixture of essential oils. Animals grazed forage sorghum under a rotational grazing system, with a forage allowance of 8 kg DM/100 kg BW during the first 28 days and 10 kg DM/100 kg BW during the final 28 days, and were housed during daytime with access to water and shade between 10:00 and 17:00 h. Results indicated that steers grazing forage sorghum without supplementation during summer achieved weight gains close to maintenance (0.070 kg/day). Supplementation with DDGS at 0.5% of BW significantly improved (P < 0.001) productive performance, increasing average daily gain (0.620 kg/day), an effect mainly attributed to the greater energy and protein supply from the supplement (supplementation response of 0.545 kg/day), with an average feed conversion efficiency of 2.73:1 and no differences among supplemented treatments (P > 0.05). Physiological and behavioral measurements suggest that, under the experimental conditions—where 87% of the experimental period was classified as being at risk of heat stress—essential oils did not contribute to improving thermal comfort in steers during the summer, as no clear positive response was observed in treatments including them. In this context, the use of an additive composed of cinnamaldehyde, silicic acid, mono- and diglycerides of fatty acids, and allicin (in proportions of 43, 37, 13, and 7%, respectively) did not show additional clear productive or physiological benefits under the evaluated conditions.

Evaluación de características morfogenéticas aéreas en gramíneas forrajeras con distinta velocidad de flujo de tejidos

Ana Lucía Dávila Casco — 2026-03-13

Natural grasslands are the foundation of Uruguay’s livestock production and play a key role in biodiversity conservation and in maintaining the stability of productive systems. In this context, it is essential to understand the strategies of forage species that sustain the productivity and resilience of these ecosystems. One of the farmeworks of plant functional traits distinguishes between acquisitive species, characterized by rapid growth and high short-term productivity, and conservative species, which exhibit slower growth, greater longevity, and higher stress tolerance. Morphogenetic traits are key indicators of these strategies, as they reflect how species allocate and utilize resources. However, there are still few studies that systematically compare these traits under the acquisitive–conservative conceptual framework in local forage species. In this study, four contrasting species were analyzed, with Lolium arundinaceum (Schreb.) Darbysh (Festuca arundinacea) used as a reference species, in order to evaluate the morphological differences associated with each functional strategy.

Efecto del procesamiento del grano de lupino sobre la respuesta a la suplementación de terneros pastoreando raigrás

Agustín Curbelo Corbo — 2026-02-24

The experiment was carried out at the Intensive Meat Production Unit (UPIC) of the Estación Experimental “Dr. Mario A. Cassinoni”, Facultad de Agronomía, in the department of Paysandú. The experimental period took place from June 26, 2024, to September 3 of the same year, totaling 70 days. The aim of the study was to evaluate the effect of lupine supplementation and its processing on animal production, as well as feed use efficiency in calves grazing on ryegrass cv Selva with restricted forage supply (2.5% DM). A total of 33 castrated Hereford calves born in the spring of 2023, weighing 154.8 ± 10.4 kg, were evaluated. The calves were blocked by live weight, forming 3 groups, and randomly assigned to 9 groups, which were then assigned to one of 3 treatments (Control: no supplementation; SLQ: supplementation with cracked lupine; and SLE: supplementation with whole lupine), resulting in 3 replicates per treatment with 4 animals each. A rotational strip grazing was carried out with 7 days of occupation, varying the plot area according to the available dry matter and the last live weight recorded for each replication. The lupin grain (Lupinus angustifolius) used to supplement the animals was supplied daily at a rate of 1% of live weight on a dry matter basis, adjusted according to the last live weight of each replication. Animal performance, measured as average daily live weight gain, was significantly higher for supplemented animals, not varying significantly according to the degree of grain processing, recording values of 0.44 kg/day, 0.84 kg/day, and 0.94 kg/day for the control, whole, and cracked treatments, respectively. The conversion efficiency achieved was 4.54 and 3.92:1 for SLE and SLQ, respectively, with no significant differences between them (p=0.498). Dry matter intake from forage showed significant differences (p=0.0141) between supplemented animals and controls, showing a substitution effect of forage by supplement, affecting pasture utilization where there was a 14% lower intake for supplemented animals.

Caracterización de los toros padre evaluados genéticamente en las poblaciones Angus y Hereford de Uruguay

Santiago Fletcher Baratta — 2026-02-13

Uruguayan cattle production has undergone a process of transformation since the second half of the nineteenth century with the introduction and consolidation of the Hereford (1864) and Aberdeen Angus (1888) breeds; initially, selection was based on subjective criteria, later incorporating objective information through population genetic evaluations from the 1980s onward, which allowed the estimation of breeding values using Expected Progeny Differences (EPD), although the performance of imported genetics may be affected by genotype × environment (G×E) interaction, since international evaluations do not always consider local production conditions; the objective of this study was to determine the origin of sire bulls of the Aberdeen Angus and Hereford breeds recorded in the population genetic evaluations of INIA Uruguay and to compare their genetic values; for this purpose, data from Genética Bovina (INIA & ARU, 2024a, 2024b) were used and complemented with genealogical records from the Asociación Rural del Uruguay (ARU), reconstructing pedigree trees to identify the country of origin of ancestors and classifying animals according to the combination of origin of their paternal ancestors (sire, grandsire, and great-grandsire), followed by statistical comparison of mean EPDs for several productive traits; in the Angus breed, although 68% of the sires were born in Uruguay, a predominance of foreign ancestry was observed, mainly from the United States and Argentina, with the purely U.S. origin combination showing, on average, the most favorable EPD values for growth and carcass traits, whereas the purely Uruguayan combination showed the best averages for lower birth weight and higher milk ability; in the Hereford breed, a lower diversity of origins and a higher proportion of animals with purely national paternal genetics were observed; the results indicate that most Angus sires show foreign ancestry, although the increasing presence of animals with Uruguayan ancestors and the identification of nationally bred animals with superior EPDs for certain traits demonstrate progress in local genetics and highlight the importance of considering genetic origin according to the specific productive objectives of each production system.

Uso de bioestimulantes con herbicidas y sus efectos en la fitotoxicidad y rendimiento de soja

María Belén Soto Caposis — 2026-02-10

The use of biostimulants in combination with herbicides has been proposed as a strategy to mitigate the expression of phytotoxicity in field crops and to help maintain yield. However, crop responses may vary depending on environmental conditions, herbicide type, and management practices. In this context, the objective of this study was to evaluate the use of a biostimulant applied in mixture with herbicides and its effects on phytotoxicity, nodulation, and yield in soybean. The experiment was conducted at an experimental site located in the department of San José, Uruguay. A completely randomized design with seven treatments and five replications was used. Treatments consisted of the application of herbicides applied in post-emergence of the crop (fomesafen, S-metolaclor, and benazolin etil + fomesafen), applied alone and in combination with the biostimulant PROGEN Detox, as well as an untreated control. Crop phytotoxicity was evaluated at 5, 14, 30, and 45 days after application. Nodulation was assessed at reproductive stages R3–R5, and final yield was determined at harvest by sampling the experimental plots. Phytotoxicity data were analyzed using non-parametric tests, applying the Kruskal–Wallis test at each evaluation date and the Friedman test to account for variability among replications. Nodulation was analyzed using analysis of variance with a model that considered plant nesting within plots, complemented by non-parametric analyses for individual variables. Final yield was analyzed using analysis of variance. Initial phytotoxicity symptoms were observed in treatments including S-metolaclor; however, these symptoms were visual and transitory, with no persistence in later evaluations, and a progressive crop recovery was observed throughout the growing cycle. No statistically significant differences were detected in phytotoxicity between treatments with and without the biostimulant in subsequent evaluations. Likewise, no significant differences were found in nodulation or yield among treatments. In summary, under the evaluated conditions, the use of the biostimulant PROGEN Detox in mixture with herbicides did not generate differential effects on phytotoxicity, nodulation, or yield in soybean, highlighting the importance of environmental conditions and the crop’s physiological compensation capacity in the observed response.

Conservación de variedades criollas de maíz y coexistencia con transgénicos

Gastón Olano de León — 2026-02-09

Maize (Zea mays L.) is a widely cultivated crop in Uruguay and boasts a high degree of genetic diversity, represented by landraces conserved ex situ and in situ – on farm by family farmers. Since 2003, with the introduction of the transgenic maize variety MON810, the use of genetically modified cultivars has become widespread throughout the country. Due to the reproductive characteristics of the species, commercial cultivars can transfer their transgenic characteristics to native varieties through cross-pollination, which poses a problem for in situ - on farm conservation. In this context, the objective of this work is to characterize the levels of transgenic DNA contamination in a collection of landraces conserved in Uruguay and to generate inputs for establishing strategies that promote coexistence between transgenic crops and native varieties. Information corresponding to 54 landraces and 33 farmers was analyzed and integrated. This information came from ethnobotanical surveys conducted through semi-structured interviews, phenotypic characterizations of ear and grain, and the presence/absence of transgenic DNA using DAS-ELISA. Fisher's exact test was used to determine the association between the detection of transgenic DNA and ethnobotanical and phenotypic characteristics present in the database. A multiple correspondence analysis (MCA) was performed to graphically visualize the existence or absence of relationships between the variables analyzed as a whole and the presence of transgenic DNA, using the R 3.6.0+ program in conjunction with the “readr” “FactoMineR” and “factoextra” packages. Of the total varieties analyzed (54), 21 obtained a positive transgenic DNA detection result (38%), corresponding to 15 of the producers interviewed, from all the represented regions of the country. Differences were detected according to the primary use; varieties intended for self-consumption had positive detections less frequently than those intended for animal feed. Producers who participate in organizations had positive detections in their varieties less frequently than those who reported no ties to any producer organization. It is necessary to promote the flow of relevant information for in situ-on farm conservation of the genetic diversity of maize crops, improve access to transgenic DNA detection tools, and generate a regulatory framework that helps promote regulated coexistence between production systems that use transgenic cultivars and native varieties.

Suplementación con grano de arroz con cáscara en régimen de autoconsumo a terneros pastoreando raigrás

Maicol Jonatan Rodríguez Venturelli — 2026-02-03

The objective of this study was to evaluate the effect of supplementation with whole rice grain with husk (WRGH) and its method of delivery on intake and behavior of Hereford calves aged 9 months and weighing 170 kg ± 20 kg grazing ryegrass. The experiment was conducted at the Intensive Beef Production Unit (UPIC) of EEMAC in Paysandú, Uruguay, using 36 calves allocated to three treatments: no supplementation (Control), daily supplementation at 1.0% of body weight (DS), and ad libitum self-feeding supplementation (SF), all with a forage allowance of 2.5% of body weight. Supplement use significantly reduced forage intake by 18.5% when comparing supplemented animals with the control (P < 0.05), with a greater reduction observed in SF (33.34%). Regarding forage selection, calves supplemented ad libitum consumed forage with a higher crude protein content than that originally offered. In terms of animal behavior, the control group showed a higher probability of grazing (50%, P < 0.01) compared with the other treatments. Among supplemented animals, those in DS spent more time grazing than SF (35%, P < 0.01). No significant differences were observed in rumination activity between supplementation methods, although rumination time was greater in supplemented animals than in the control. Residual biomass was 56.8% higher in supplemented treatments, indicating lower forage utilization. This difference was especially marked in SF, where forage utilization was estimated at 38.3%. In comparison, the DS treatment showed a utilization of 52.1%, while the control reached 62.9%. In conclusion, supplementation with WRGH particularly under ad libitum conditions reduced forage intake and grazing time, while increasing pasture selectivity. This resulted in greater supplement intake, higher forage substitution, and lower efficiency of forage utilization.

Impacto del nivel de rastrojo de sorgo sobre la implantación y rendimiento del maíz

Serafín Bachino Introini — 2026-01-16

In recent years, part of agricultural systems takes advantage of crop residues as by-products. The objective of this study was to evaluate the effect of different levels of sorghum and wheat residue removals on maize establishment and, the effect of nitrogen addition on grain maize yield. It is important to study how the interaction between nitrogen addition and residue removal is reflected in maize yield, evaluating this in two different rotational systems. The experiment was conducted during the 2024–2025 growing seasons, from October of the first year to April of the second, at the Faculty of Agronomy, “Mario A. Cassinoni” Experimental Station, in the department of Paysandú, Uruguay. Both evaluated systems have a two year duration, which are: wheat–grain sorghum-maize and wheat–forage sorghum-maize. Some of the variables measured were: crop establishment, soil nitrate levels at pre-sowing and during the growing season, soil water infiltration, and yield components. By separating the systems, considering rotations, into one with three residue removal levels (0%–40%–80%) and another with two levels (0%–80%), it was observed that, in the first case, there were no significant differences in most of the variables studied. The only scenario where an effect was found, was in the first infiltration measurement. When evaluating removal of 0%-80% (both systems), there were differences found in most of the measured variables. Regarding soil nitrates, differences were observed in the sample taken at crop emergence, having elevated levels the one where residue was left in the surface; no differences were found in the remaining measurements, although a trend was observed toward a decrease in soil nitrates at the V7 stage after crop establishment across all treatments. In the infiltration analysis, it was observed that residue content on the soil surface is of great importance, as treatments where all the residue was retained, showed a considerable improvement in infiltration. Regarding yield and its components, when evaluating only residue removal, superior results were obtained when residue was removed. However, when system and residue removal interacted, the highest yield was maintained when residue was left on the soil surface, although no significant differences were observed, compared to residue removal in system two. Regarding nitrogen addition, no differences were observed in either of the two evaluated systems.

Modelos de predicción de biomasa en sistemas de producción lechera usando índices de vegetación de drones e imágenes satelitales

María Victoria González Techera — 2025-12-30

Accurate estimation of pasture biomass is essential for decision-making in grazing systems, it requires information obtained at different spatial scales using diverse measurement methods. This study integrates multiple datasets generated from experiments conducted at the Centro Regional Sur (CRS) Research Center, combining direct field measurements, such as: sward height measured with a ruler, compressed height obtained using a rising plate meter (RPM), and C-Dax pasture meter, using the Normalized Difference Vegetation Index (NDVI) derived from drone and satellite imagery. The goal was studying the relationships between structural and spectral vegetation variables and performance evaluation of different predictive models of pasture biomass.

Results revealed consistent and predominantly non-linear associations between direct measurements and NDVI, particularly for drone-derived NDVI, where patterns related to index saturation and differences in canopy architecture among species were observed. Models based on direct field measurements showed higher explanatory power at the fixed-effects level; however, models built using drone-derived NDVI achieved comparable predictive performance during validation. In addition, the satellite-based NDVI model exhibited greater stability and performance comparable to or better than the drone-based model, likely due to its broader spatial scale, which attenuates fine-scale within-paddock heterogeneity.

Overall, these findings highlight the complementarity between in situ measurements and remote sensing data, and support the use of integrated approaches for pasture biomass prediction. Such integration balances accuracy, applicability across different spatial scales, and practical implementation, offering strong potential to improve grazing management decisions and production planning.

Comparación de dos métodos de extracción de líquido ruminal (fístula vs sonda) a partir de la población bacteriana obtenida en vacas Primiparas durante el periodo de transición

Santiago Nahuel Techera Pintos — 2025-12-30

The quest to improve the efficiency and sustainability of dairy production has led to research into the complex ruminal microbiome system, and in this context, the extraction of ruminal fluid samples is a critical step. The standard method for extraction is through the ruminal fistula, which offers accurate sampling but raises methodological questions regarding animal welfare and makes it more difficult to perform mass sampling, as it involves surgery in the flank area. As an alternative, the oro-ruminal probe is a less invasive and more practical method for obtaining multiple samples. The objective of this study was to compare the use of the oro-ruminal probe versus the ruminal fistula as a sampling methodology to characterize the prokaryotic microbial community of the rumen in primiparous Holstein cows during the transition period, evaluating similarities and differences in microbial composition and structure at three time points around calving (-30, +35, and +65 days). Nine Holstein-American heifers cannulated at the rumen level underwent ruminal fluid extraction using both methods at the three time points around calving. Samples were taken in the morning when the animals were fasting. Each sample was placed in a sterile, labeled 50 ml tube. These samples were centrifuged at 10,000 rpm, 4°C, for 10 minutes, and the sedimented material was extracted using sterile pipettes, transferring it to two sterile, properly labeled 2 ml bottles. These small vials are the sample from which the microbial population was evaluated and were stored at -80°C. The microbial population of each sample was detected by amplifying the variable regions V3-V4 of the 16S gene and paired-end sequencing with the Illumina MiSeq platform. The objective was to group the sequences at the ASV (Amplicon Sequence Variants) level to characterize the taxonomic groups at the microbial genus level using the public Silva database (version 138.2). The DADA2 package of the R statistical software (version 4.3.1) was used for statistical analysis. Rarefaction curves showed that the sequencing depth was adequate. The richness and diversity of ASVs and microbial genera did not show significant differences between sampling methods (p >0.05). The mean Pearson and Spearman correlations according to sampling time for the relative abundances of microbial genera using fistula and probe were high (r >0.7) but decreased from prepartum to postpartum. Differential expression analysis showed that none of the evaluated genera presented differences between methods (padj >0.05). The %CV of relative abundances of genera between sampling methods increased according to sampling time, from 8.7% at time -30 to 15.4% at time +35, and 26.6% at time +65. On average, the probe shared 85.8% of the central genera detected by the fistula extraction method. Therefore, the use of the oro-ruminal probe was able to characterize and provide a good biological signal about the microorganisms in the ruminal fluid, which suggests that it is a reliable alternative for evaluating the ruminal environment.

Caracterización de la raza Red Poll en Uruguay

Edgardo Franchi de Gregorio — 2025-12-29

This study aimed to characterize the Red Poll cattle breed in Uruguay through the analysis of its historical background, morphological and productive attributes, and its evolution within the national institutional framework. Data were collected from the Red Poll Breeders’ Society, surveys administered to producers associated with the breed, historical genealogical records from the Asociación Rural del Uruguay (ARU), and an in-depth case study of the “San Florencio” livestock operation. The methodology included the collection of qualitative and quantitative information regarding production orientation, management practices, selection criteria, perceived limitations, and improvement strategies; simultaneously, productive variables recorded at the studied farm—such as pregnancy rates, weaning weights, average daily gains, selection parameters, and prioritized breed traits—were analyzed. Historical ARU records were also examined to contextualize the breed’s development and consolidation within the country. The results demonstrated that Red Poll cattle exhibit relevant productive attributes that position the breed as a viable alternative for national cow–calf systems, including hardiness, feed conversion efficiency, calving ease, docility, longevity, and dual-purpose aptitude. Additionally, these characteristics enable the breed to adequately meet current market demands, particularly regarding efficiency, meat quality, and adaptability to extensive systems. However, its development is constrained by the predominance of other, more widely disseminated and established breeds in the national market, along with limited visibility, a reduced population base, the lack of systematic productive records, and the risk of inbreeding. It is concluded that strengthening the breed’s presence in Uruguay requires enhancing promotion strategies, consolidating genetic improvement programs, incorporating external genetics to expand population diversity, and improving record-keeping and traceability systems. The characterization conducted provides valuable insights for the understanding, appreciation, and potential strengthening of the breed within the national livestock sector.

Aportes de franjas de Thinopyrum intermedium a la gestión integrada de plagas del cultivo de soja

Alfonso Marcel Thome Riera — 2025-12-29

Soybean (Glycine max) is the main agricultural crop in Uruguay, but its intensification poses serious challenges for pest management due to insect resistance and environmental contamination. In this context, Integrated Pest Management (IPM) promotes the use of reservoir areas to enhance the presence and abundance of natural enemies. The general objective of this study was to evaluate the contribution of Thinopyrum intermedium (intermediate wheatgrass), a winter perennial grass of dual purpose, to IPM in soybean crops. The specific objectives were to examine the effect of distance from T. intermedium strips on the abundance of predatory and herbivorous arthropods. We hypothesized that predator abundance would decrease and herbivore abundance would increase with increasing distance from the strips. The experiment was conducted at EEMAC, Paysandú, Uruguay, using four permanent T. intermedium strips parallel to the soybean crop. Sampling points were established in the tinopiro, in a strip of spontaneous vegetation, and within the soybean crop at 10, 25, 40, and 55 meters from the edge. Sampling was carried out biweekly using an entomological sweep net in all habitats and a vertical beat cloth within soybean. Abundance in each habitat (T. intermedium, spontaneous vegetation, and soybean) was analyzed using Generalized Linear Mixed Models (GLMM) with a negative binomial distribution due to overdispersion. Habitat was included as a fixed effect, and date and block as random effects. When “Habitat” was significant, post-hoc comparisons were performed using the emmeans package with Sidak adjustment to detect differences among habitats. In addition, arthropod abundance was modeled through GLMM with a negative binomial distribution, using distance from tinopiro as a fixed effect and date and block as random effects. Models with linear and quadratic terms were compared, selecting the best according to AIC. A total of 7,389 arthropods of interest were collected, 34% of which were natural enemies (predators and parasitoids). The abundance of natural enemies and predators was significantly lower in soybean than in tinopiro and spontaneous vegetation. Their abundance decreased linearly and progressively with increasing distance from the tinopiro toward the interior of the crop. Tinopiro presented higher abundances of lacewings and spiders. In contrast, herbivores were concentrated in soybean. Our results indicate that the inclusion of Thinopyrum intermedium strips is a promising strategy for enhancing the presence of beneficial arthropods and contributing to the functional diversification of the system. Perennial strips act as key refuges and resource sources for natural enemies. The pattern of decreasing predator abundance and the concentration of herbivores in soybean (farther from the edge) reinforces the hypothesis that tinopiro may indirectly contribute to natural pest control through the conservation of natural enemies in the immediate vicinity of the crop. Thus, tinopiro emerges as a multifunctional component that integrates production (grain and forage) with the conservation of beneficial fauna, aligning with the principles of ecological intensification to achieve more sustainable agricultural–pastoral systems in Uruguay.

Evaluación de insecticidas curasemillas en colza

Richart Manuel Moriondo Algalarronda — 2025-12-29

The cultivation of canola has increased its relevance within agricultural systems in Uruguay. During crop establishment, several pests represent a limitation to proper stand development. One management strategy commonly used is the application of seed treatment insecticides, which enable early-stage pest control while reducing, due to their mode of application, the impact on non-target organisms. However, there is concern regarding potential phytotoxic effects on seeds, as well as the effectiveness of pest control under different environmental conditions. In this study, three seed treatment insecticides were evaluated: thiodicarb (Lider 30 SC), cyantraniliprole (Cinatra 60 FS), and clothianidin (Clothiex 600 FS), applied to canola seeds (cv. Nuvette 2286). Controlled-environment assays were conducted to determine germination percentage at 0, 4, 10, and 20 days after treatment, and field experiments (at two sowing dates) were carried out to assess the effectiveness of pest control during crop establishment. Results indicated that none of the evaluated seed treatments exhibited phytotoxic effects on germination, with all values remaining above the commercial standard (80%). The duration of contact with the insecticides slightly influenced germination, showing a significant decrease at 20 days after treatment; however, values remained above 80%, thus meeting commercialization standards. In field trials, the low pest incidence prevented the evaluation of control efficacy, likely due to climatic factors regulating pest populations. The information provided is useful for selecting seed treatment insecticides in canola, emphasizing the importance of considering application rate, environmental conditions, and storage time of treated seeds.

Filogenómica de Feijoa sellowiana (O. Berg) O. Berg (“guayabo del país”) tipo Uruguay y Brasil basado en pan-plastoma

Mauricio Pesce López — 2025-12-26

In Uruguay, the native feijoa (Feijoa sellowiana, Myrtaceae), also known as the “guayabo del país,” is the native woody species with the greatest potential for commercial fruit production and derived products. The “Uruguay type” and “Brazil type” variants are recognized. The development of cultivars at the regional and international levels is recent and stems from the “Uruguay type,” “Brazil type,” or their hybrids. However, there is little information to help clarify the recent and historical phylogenetic relationships among wild accessions, domesticated forms, and cultivars.

The reduction in the costs of massive sequencing technologies makes it possible to implement intraspecific genetic studies based on complete chloroplast genomes, rather than traditional universal markers. There are no precedents for implementing these studies in feijoa. In this study, a new version of the feijoa plastome annotation was developed and validated. Additionally, a feijoa pan-plastome was generated for the first time, including 33 accessions (wild, selections, and cultivars) from Uruguay, Argentina, Brazil, and New Zealand.

The feijoa pan-plastome ranged from 159,330 bp to 159,401 bp in length and encoded 117 unique genes. In total, 51 indels, 135 SNPs, and 13 haplotypes were detected. Three hypervariable intergenic regions (rps16-trnQ(UUG); psbZ-trnG(GCC); ndhF-rpl32) were used to develop new markers for the species. No significant evidence of adaptive selection was identified among the protein coding genes.

The phylogenetic analysis divided the accessions into two main clades, which largely separated the “Brazil type” variants (clade 1) from the “Uruguay type” variants (clade 2). Clade 1 included 10 Brazilian accessions (three cultivars) and one New Zealand cultivar. Furthermore, this clade corresponded to haplogroup 1, including six of the 13 haplotypes identified in this study. For its part, clade 2 comprised two subclades and one orphaned Brazilian accession. Subclade 2.1 included two Brazilian accessions (one cultivar) and three Argentinian ones, for which some data suggest that they produce fruits of intermediate size between the “Uruguay type” and the “Brazil type”; this clade corresponded to haplogroup 2 (four haplotypes). Subclade 2.2 preferentially grouped the “Uruguay type” accessions, including the Uruguayan accessions (four cultivars), six New Zealand cultivars, and one Brazilian cultivar. This subclade corresponded to haplogroup 3, which consisted of only two haplotypes, with representatives of cultivars and accessions from Uruguay in both lineages. This study reports the first evidence of clear evolutionary differentiation between the “Uruguay type” and the “Brazil type” based on pan-plastome data; it also identified two chloroplast lineages for Uruguayan guavas and two others for Argentine guavas, and found that 10 cultivars derived from three breeding programs (Uruguay, Brazil, and New Zealand) share a common maternal lineage originating in Uruguay.

Overall, this study provides new evidence on the genetic variability of the species and contributes to our understanding of its evolutionary history, as well as the recent processes of domestication and genetic improvement. These topics warrant further investigation in future studies.

Perfil de ácidos grasos en carne de novillos Wagyu alimentados con subproductos derivados del cacao

Axel Galiaz Piriz — 2025-12-22

This study evaluated the influence of breed and cocoa by-product supplementation on the fatty acid profile of muscle and subcutaneous fat in Wagyu steers, comparing them with a conventional Aberdeen Angus (NW) feedlot system. Wagyu consistently showed a more unsaturated lipid composition, with higher MUFA particularly oleic acid and lower SFA than the Angus group, reinforcing its reputation as a premium beef.

When tissues were analyzed separately, muscle exhibited a higher proportion of unsaturated fatty acids, whereas subcutaneous fat contained more SFA, CLA and branched-chain fatty acids. These differences align with bovine lipid deposition physiology and help explain nutritional variation among cuts.

Cocoa by-products did not significantly change the fatty acid profile of Wagyu, indicating that supplementation can be used without compromising lipid quality. Overall, the results support Wagyu as a valuable option for intensive finishing systems in Uruguay and contribute evidence for differentiated, high-quality beef production strategies.

Diagnóstico y propuesta de re-diseño de un sistema de producción ganadero pastoril sobre campo natural

Florencia Barreneche Sosa — 2025-12-22

Family livestock farming is a productive activity with economic, social, and environmental relevance in Uruguay, but generally exhibits low production efficiency. This document contains a study of a production system, which involved characterizing, diagnosing, and formulating a redesign proposal based on the family's objectives and available resources, considering environmental, economic, and social dimensions through comprehensive analysis. To understand the activities and objectives of the farmer and their family, the protocol for capturing the functioning of livestock systems (Faculty of Agronomy, Grazing Ecology Group) was used, through scheduled visits, focusing on the feeding, health, and reproduction of cattle and sheep. Subsequently, to understand the system and plan a redesign, the MESMIS method was applied to assess the property's sustainability, identifying critical points and constructing a problem tree to establish cause–effect relationships and prioritize them. The redesign proposal aimed to improve the productive and economic efficiency of the system, reflected in indicators such as equivalent meat production, weaning rates and weaning weights, and farm income, by introducing changes in forage management, improving the production and utilization of natural pasture, implementing profitable techniques with a significant production impact, and leveraging available resources.

Evaluación de raíces en portainjertos serie Geneva ®

Antonio Saracho Poses — 2025-12-19

The rootstocks most used in apple production in Uruguay over the past decades (M.9 and M.7) are being replaced by Geneva series rootstocks. The latter were developed in the 1990s due to their resistance to pests and diseases, as well as their tolerance to replant conditions, among other positive characteristics.

In 2001, the National Institute of Agricultural Research (INIA) signed an evaluation agreement with Cornell University, leading to the introduction of these rootstocks to the country. A further introduction of new materials from the series followed in 2017. Despite the positive characteristics reported for this series, there is uncertainty regarding their agronomic performance both globally and nationally.

Root growth dynamics are one of the aspects that have been under-evaluated. This is the first study to characterize Geneva rootstocks using the mini-rhizotron method in the field.

In this study, six combinations of the Lady in Red variety with the most promising rootstocks of the Geneva series were evaluated through studies of root development, shoot growth, and fruit size. Evaluations were carried out in the fourth year after planting, during the 2022-2023 growing season at the INIA “Las Brujas” facilities in the department of Canelones. A randomized complete block design with three replicates of four trees each was used. Root measurement tubes with a scanner were installed in the central plant of each plot and shoot growth and fruit size variables were evaluated on one branch per tree, with three trees per replicate. The study year presented severe water deficit conditions, leading to an agricultural emergency declaration by the Ministry of Livestock, Agriculture, and Fisheries. During this cycle, no significant differences were observed between rootstocks in the evaluated root variables, except for root area at depth, where rootstock G.210 showed a greater root area at a greater depth. No significant differences were observed between the rootstocks in shoot growth; however, a trend toward greater overall growth was observed in rootstock G.213. Significant differences were found in fruit size, with rootstock G.213 differing from G.210.

We consider these data to be of great value when defining planting criteria such as planting pattern, density, and training systems. Further measurements should be taken in subsequent cycles to better understand the growth dynamics of the different root systems of these rootstocks.

Dinámica de la agricultura en el Uruguay y su evolución en el periodo 2015 – 2023

Sofía Pejo Henderson — 2025-12-19

The absence of reliable information on crop yields and sown area at subnational level represents a limitation for analyzing agricultural dynamics in Uruguay and for estimating yield gaps. Official agricultural statistics are reported almost exclusively at the national scale, without reflecting the spatial heterogeneity that characterizes the country’s production systems. In response to this limitation, the aim of this study was to generate, for the first time, departmental-level maps of sown area and yield for soybean (first season, second season, and irrigated), maize (first season, second season, and irrigated), wheat, barley and brassicas for the period 2015–2023, using an unprecedented dataset of more than 10.000 producer-level records from DIEA’s Agricultural Surveys, fully processed and systematized in RStudio.

A consolidated and standardized database was developed from the Winter and Spring Surveys, followed by a cross-validation process using national and international official sources to evaluate the consistency of the estimates. The resulting maps provide a detailed visualization of the spatial distribution of agricultural productivity and sown area across the country. Additionally, temporal trends in total agricultural area and crop-specific yield trajectories were analyzed to identify structural changes over the study period.

Results show that, although Uruguay’s total agricultural area remained relatively stable, the production system experienced significant transformations: an increase in double-cropping, greater diversification, and a marked expansion of second-season maize and brassicas. Soybean remained the dominant crop, with more than half of the sown area concentrated in the western departments (Soriano, Río Negro and Colonia), which also exhibited the highest yields and lowest interannual variability. For maize, irrigated systems showed clear advantages in both yield and stability, positioning irrigation as a key strategy for coping with climatic variability.

Evaluación de la calidad de la carne bovina producida en dos sistemas de producción

Felipe Grolero García — 2025-12-19

Uruguay has experienced a significant expansion in beef production in recent years, accompanied by technological advances both in production systems and commercial practices. The increased use of confinement production systems has raised questions regarding their impact on the quality of the final product. In this context, the present study seeks to analyze the effect of two contrasting production systems (pasture and feedlot) on beef quality. For this, twelve vacuum-packaged loin cuts (psoas major muscle) were used, obtained from Aberdeen Angus steers raised on pasture (n=6) and in another of feedlot type (n=6), obtained from Frigorífico Tacuarembó. Steaks were extracted from these cuts, placed on trays covered with oxygen-permeable PVC film and displayed in a refrigerated showcase, simulating commercial retail conditions for 4 and 8 days. Color, pH, water loss, lipid oxidation (TBARS), total lipid content, and heme iron content were measured. For each variable, a repeated-measures ANOVA was conducted to evaluate the effect of production system and display time. A significant effect of the production system was observed on pH (p < 0.05), water loss (p < 0.05), and the L* parameter (lightness) (p < 0.01), with feedlot beef showing higher values than pasture-raised beef. No significant differences between systems were found for the other color parameters —a* (redness), b* (yellowness), hue, or chroma— nor for TBARS, lipid content, and heme iron content. Regardless of the production system, there was a significant decrease in redness (p < 0.0001), resulting in a reduction in color saturation (chroma, p < 0.0001) from day 0 to day 4, as well as an increase in lipid oxidation from day 0 to day 8 (p < 0.0001). Therefore, feedlot beef was lighter in color, consistent with previously reported literature, and exhibited greater water losses. In conclusion, certain technological quality attributes of beef can be influenced by the production system, however, the results obtained do not allow us to affirm that pasture-raised beef is of superior quality to feedlot beef.

Índice de área foliar en sistemas silvopastoriles en Eucalyptus grandis y dunni

Diego Martínez Vila — 2025-12-17

This study evaluated the vertical distribution of leaf area index (LAI) and light transmittance in a silvopastoral system with Eucalyptus grandis and Eucalyptus dunnii, comparing single-row and triple-row planting arrangements. Ten representative trees were selected, and each crown was subdivided into four strata. In each stratum, light transmittance was measured using a ceptometer, and LAI was estimated with the LAI-2200 canopy analyzer. A destructive determination of leaf area was later performed through digital leaf scanning to compare with the indirect measurements. E. grandis exhibited a mean height of 4.7 m, a diameter at breast height (DBH) of 4.6 cm, and a live crown height of 4.4 m, exceeding E. dunnii by 1 m, 0.66 cm, and 0.7 m, respectively. Light transmittance followed a negative exponential function and was influenced by both species and planting arrangement. LAI values were low in the single-row arrangement (0.3–0.4) and substantially higher in the triple-row arrangement (1.2–2.1). The indirect method (LAI-2200) consistently underestimated LAI compared with the destructive WinDIAS measurements. In the single-row arrangement, species differed markedly in transmittance: in the H0–H1 stratum, E. grandis showed 57% lower transmittance than E. dunnii, while differences in the H1–H2, H2–H3, and H3–Crown strata were 22%, 50%, and 11% respectively, always with lower values for E. grandis. In contrast, in the central row of the triple-row arrangement, the pattern reversed, and E. grandis exhibited 58% higher transmittance than E. dunnii in the H0–H1 stratum. The combined characterization of light transmittance and LAI provides relevant information for the design and management of silvopastoral systems with Eucalyptus spp., offering tools to optimize resource use and improve system viability by understanding how these variables influence both tree growth and understory forage production.

Uso de isótopos estables para la cuantificación de la incorporación de carbono orgánico al suelo en plantaciones de segunda rotación de Eucalyptus dunnii

Ignacio Cánepa Penadés — 2025-12-16

In recent decades, forestry production in Uruguay has grown steadily, establishing itself as an important pillar of the national economy. This development has led to a significant expansion of the area occupied by plantations of exotic species, mainly of the genus Eucalyptus, to the detriment of natural grassland cover. Not only has the forested area increased, but it has also been consolidated over time through second-rotation plantations. This change in land use can affect the physicochemical properties of the soil, particularly soil organic carbon (SOC) stock, a fundamental component of fertility, environmental quality, and ecosystem resilience.

This study was conducted in commercial plantations of second-rotation Eucalyptus dunnii (E. dunnii) belonging to the company UPM Forestal Oriental S.A., located in the department of Paysandú. The overall objective was to quantify the SOC contribution generated by these plantations using isotopic fractionation techniques. Also, SOC contents were compared with those of adjacent areas covered by natural grasslands in order to identify carbon gain or loss processes linked to land use change.

The methodology employed focused on measuring the ratio of stable carbon isotopes (¹³C/¹²C), which allows the origin of carbon to be identified based on the type of photosynthetic metabolism predominant in the vegetation (C₃ or C₄). This isotopic technique revealed a significant contribution of forest cover to SOC.

The results showed that forest cover made a significant contribution to SOC. However, SOC concentrations in the top 10 cm of soil were higher in natural grasslands than in forested areas, suggesting carbon losses following the conversion of grasslands to forest systems. Isotopic analysis showed more negative δ¹³C values under forest cover, indicating a higher proportion of carbon derived from C3 species (Eucalyptus spp.). These findings confirm the new origin of carbon in the soil and suggest that, although COS levels do not yet reach those of native grasslands, they could stabilize at similar ranges over time.

Efecto de prácticas de manejo (poda y raleo) en el comportamiento agronómico de la variedad Albariño (Vitis vinifera L.)

Micaela Pamela Trefoglio Romano — 2025-12-16

The present study aimed to evaluate the influence of winter pruning and cluster thinning at veraison on vegetative development, yield, and berry composition of the Albariño (Vitis vinifera L.) variety in Uruguay. The interest in this study arises from the significant expansion of Albariño plantings in the country during the last decade. It is a high-vigor variety characterized by long internodes, which represents a challenge when defining the number of buds to leave during winter pruning. In this context, the possibility of increasing bud load per linear meter of wire was evaluated through the crossing of shoots from adjacent vines (cross bilateral pruning). To complete the experimental design, bilateral pruning treatments (commonly used in national viticulture) and unilateral pruning were included. Likewise, the pruning treatments were combined with cluster thinning (50%) at veraison, in order to evaluate the effect on vegetative balance and must quality. The results obtained demonstrated that pruning intensity (differential among treatments) had effects on yield, vegetative development of the vines, and berry composition. The pruning treatment with the highest number of buds (cross bilateral) presented the highest yields, associated with a greater number of clusters per vine, although with lower individual cluster weight. In contrast, the most severe prunings (unilateral and bilateral) showed lower yields, but greater pruning weight and leaf area per shoot. Cluster thinning reduced yield but favored earlier berry ripening, reflected by an increase in soluble solids content. Regarding acidity, no clear influence of pruning or thinning was observed. Likewise, no significant differences were recorded in malic and tartaric acid content, possibly influenced by climatic conditions.

Evaluación del uso de cultivo de cobertura - laboreo reducido y mulching con manejo orgánico sobre el rendimiento del cultivo de calabacín y la calidad del suelo

Camila Do Canto Rodríguez — 2025-12-16

The rotation of horticultural crops with cover crops and reduced tillage (CC-RT) is a strategic practice in agroecological systems, but its adoption is limited due to, among other factors, inconsistent results and often low yields. This study aimed to contribute to the development and validation of this technology in an agroecological system by analyzing its impact on the physical, chemical, and biological properties of the soil, as well as on the yield of zucchini squash (Cucurbita moschata Duch). The experiment was conducted at the Centro Regional Sur of the Faculty of Agronomy, Uruguay. The CC-RT system was tested using two cover crop seeding densities (D1 and D2), additional mulch (D2+M), and bare soil (BS). Regarding physical properties, bulk density and penetration resistance remained below critical thresholds for root growth across all treatments, indicating favorable conditions for root exploration and adequate aeration of the soil profile. Soil chemical and biological properties showed a dynamic response influenced by the quality of cover crop residues and environmental conditions. During winter, high basal respiration (BR) and nitrogen mineralization potential (NMP) were recorded; in spring, a peak of mineral N—mainly ammonium—was associated with the rapid decomposition of lupine residues; and in summer, despite high temperatures, treatments with greater surface cover maintained higher overall microbial activity, demonstrating that maintaining soil cover enhances the biological health of the system. Yields ranged from 45 to 49 Mg/ha. Although total yield did not differ among treatments, differences in yield components (fruit number and weight) were observed, indicating variations in the systemic functioning of the crop. The results position CC-RT and mulching as promising technologies for agroecological transition, demonstrating that it is possible to sustain high yields and improve soil quality without relying on external inputs, thereby contributing to the development of more sustainable horticultural systems.

Evolución de peso de vaquillonas hijas de vacas cruza y puras sometidas a niveles de oferta de forraje en gestación y lactancia

Fabrizio Terra Dos Santos — 2025-12-12

The objective was to study how high and low OF during breeding and crossing in the mother affected the evolution of PV of heifers during breeding. The experiment was carried out at the Bernardo Rosengurtt Experimental Station between May and November 2022. 30 heifers from an experiment in which their mothers were subjected to a factorial design of treatments of High and Low OF (8 and 6 kg M.S. / kg P.V. respectively) and genetic group of the cows (Angus, Hereford, AA x HH and HH x AA); born in the spring of 2021 (average birth date 13-09-2021 ± 93 days). The experimental design employed was a completely random design, where the experimental unit was each animal. The average weaning date was 25/02/2022 ± 8 days, with an average weight of 196 ± 12 kg. The PV of the animals was measured monthly from the beginning of the experiment until the end of it (March - November). The OF values were different depending on the season and the average annual OF was 1.7%. The PV of heifers was affected by the month, while it was not affected by the OF, genotype or interactions OF x Month and Genotype x Month. In the month of May, the weight was 207 ± 8 kg, in that period (May - June), the evolution of PV had a period of stability (P > 0.05), while in July the PV begins to increase but does not differ statistically from June, reaching a PV of 221 ± 8 kg. From August to November, the evolution of cow weight increases (P < 0.05), achieving a PV of 279 ± 8 kg in November. The weight gains of heifers tended to be affected by the Month effect, while they were not affected by OF, neither the Genotype, nor the Genotype x Month and OF x Month interaction. In the month of May, the heifers obtained an average daily gain of 0.150 ± 0.07 kg/day. In the month of June, the heifers obtained daily weight losses of - 0.174 ± 0.07 kg. In the months of July to November, they experienced weight gains, where the highest daily gains were in the months of July, August and November being of 0.64 ± 0.07 kg, 0.62 ± 0.08 kg and 0.53 ± 0.07 kg respectively (P<0.05). In the months of September and October, there is a decrease in daily earnings compared to the previous months of July and August (P<0.05), where the lowest levels of earnings are evident in the month of September being 0.23 ± 0.08 kg, while in October 0.34 ± 0.07 kg.

Caracterización de la genética importada de reproductores de razas carniceras

Juan Andrés Constantín Torres — 2025-12-12

Uruguay is an important exporter of beef, supported by predominantly pasture-based production systems and a national herd composed mainly of British breeds, particularly Aberdeen Angus and Hereford. In this context, genetics plays a key role in sustaining and improving productivity levels, making the importation of bovine semen an increasingly important strategy for genetic progress. However, there is limited systematized information regarding the geographic origin of imported semen and the breed composition, information that is essential for evaluating whether the genetic material introduced aligns with the country’s production conditions. The objective of this study was to characterize the origin of genetic material imported by Uruguay between 2020 and 2024, identifying the main supplying countries as well as the volume and breed distribution of the semen commercialized. Official records from the Ministerio de Ganadería, Agricultura y Pesca (MGAP) were used as the primary data source. These records were organized, cleaned, and analyzed using descriptive statistical methods supported by Microsoft Excel. Results show a strong geographic concentration of imports: the United States and Argentina jointly provided more than 85% of the 1,416,069 semen doses imported during the period. The United States remained the dominant supplier, while Argentina consistently contributed a significant share. Other countries—such as Australia, Canada, Spain, Germany, and England—displayed much lower and often irregular participation. Regarding breed composition, the findings confirm the predominance of Aberdeen Angus and Hereford, which form the genetic foundation of the Uruguayan beef herd. Angus imports remained stable at around 200,000 doses per year, with the United States as the main source. In the case of Hereford, although the United States also led, Australia played a notable role in 2022, when this breed reached its peak volume of imports. A gradual diversification of genetic sources was also observed, with the incorporation of synthetic breeds such as Brangus and Braford—almost exclusively sourced from Argentina—and specialized breeds such as Wagyu, which increased its presence in recent years. These patterns reveal a marked dependence on genetic sources developed under production systems that differ from Uruguay’s extensive pastoral model. This raises challenges related to genotype × environment interactions, since materials evaluated under intensive conditions—particularly in the United States—may not fully express their genetic potential under pasture-based systems. This highlights the need for local validation mechanisms to ensure the adaptive performance of imported genetics. In conclusion, this study provides a detailed characterization of Uruguay’s recent bovine semen import trends, principally from intensive systems, the predominance of British breeds, and the emergence of genetic diversification. The results reinforce the importance of complementing imported genetics with national evaluation and selection programs that ensure adaptation to Uruguay’s production environment, promoting sustainable genetic progress aligned with the country’s pastoral systems.

comportamiento en pastoreo durante el verano en vacas Charolais en el litoral norte del Uruguay

Macarena Garcimartín Pereira — 2025-12-11

In northern Uruguay, cattle production is mainly focused on meat production, carried out in extensive pastoral systems characterized by high temperatures and marked seasonal variations in forage availability. In this context, the breeds selected must combine productive performance with adaptability to hot climates and resistance to diseases and parasites. The breeds most used in production are British breeds such as Hereford and Aberdeen Angus; however, in the environmental conditions of the north of the country, their welfare is compromised by high summer heat load. The Charolais breed is characterized by its hardiness, high weight gain, and adaptability to diverse environments, which positions it as a genetic resource of interest. In this context, the objective of this study was to determine the grazing behavior of Charolais breeding cows, according to adjusted THI, managed on natural pasture, under conditions of heat stress during the summer in Paysandú, Uruguay. This involved determining the daily time spent grazing, in the shade, resting in the sun, ruminating, and drinking water. The study consisted of visual monitoring for three consecutive days from 7:00 a.m. to 6:00 p.m., recording the animals' activity (grazing, resting in the sun, resting in the shade, ruminating, and drinking water) every 10 minutes. At the same time, the Temperature and Humidity Index adjusted for wind speed and solar radiation (THIadj) was quantified to measure the risk of heat stress in the animals evaluated, being 78 (alert), 81 (danger), and 80 (danger), respectively, for each day of measurement. Statistical analysis showed differences in behavior according to variations in THIadj, with a decrease in grazing as the index increased (r = -0.19), an increase in the use of shade (r = 0.35), and a substitution of resting (r = -0.37) and water-seeking behaviors (r = -0.24) for staying in the shade. Likewise, there was no correlation between THIadj, and the time spent drinking water. On average, within the total hours of observation, cows spent 4.6 hours grazing, 2.6 hours resting in the sun, 0.6 hours ruminating, 3.6 hours in the shade, and 0.4 hours at the watering hole, with a frequency of visits to the water of 2, 4, and 3 times per day, respectively. In conclusion, the results confirm the importance of access to shade as a determining factor for the welfare and productive efficiency of cattle exposed to hot conditions. For this reason, it is relevant to consider the necessity to include the environmental component to daily planning.

Estudio de variables fisiológicas en condiciones climáticas de verano en la raza Charolais en el litoral norte de Uruguay

Felipe Lanfranco Dutra da Silveira — 2025-12-08

Heat stress is one of the main challenges for livestock production in subtropical regions, where high temperatures, high relative humidity and intense solar radiation affect productive efficiency, animal welfare and the sustainability of pastoral systems. In Uruguay, the frequency and intensity of extreme heat events have increased in recent decades, especially on the northern coast, where climatic conditions increasingly exceed critical thresholds for livestock. In this context, understanding the physiological responses of breeds used in beef production is essential to develop management and genetic selection strategies aimed at climate resilience. The Charolais breed, of French origin and recognized for its high meat yield, had an important presence in Uruguay, although its population decreased due to its large size and higher nutritional requirements. However, its light coat and recent evidence of intra-racial variability in heat tolerance suggest a higher adaptability than expected, justifying its re-evaluation in subtropical environments. The objective of this study was to evaluate physiological responses to heat stress in Charolais cattle during the summer in Paysandú, Uruguay. We worked with 21 animals of different categories (bulls, bulllets, cows, heifers, calves and heifers) kept in natural range. Seven measurements were taken between December 2024 and January 2025, at critical times (07:00 and 14:00 h). Climatic variables were recorded and the Temperature and Humidity Index adjusted for wind speed and solar radiation (ITHaj) was calculated. During November-February, the average ITHaj was 79.3±5.8, corresponding to thermal emergency conditions, with a maximum of 91.5 in mid-afternoon. The herd remained 49 days in emergency, 27 in danger and only 4 days in thermal comfort. A positive correlation was observed between ITHaj and rectal temperature (TR; r = 0.43) and between ITHaj and respiratory frequency (FR; r = 0.61). During the morning (ITHaj 47.7-73), animals maintained TR between 38.3 and 39.4 °C, FR between 40 and 56 rpm, forehead temperature (TFr) between 31.3 and 36.6 °C and flank temperature (TFl) between 34 and 36.6 °C, indicating thermal stability. In the afternoon (ITHaj 78.5-90), all variables increased significantly: TR up to 40.2 °C, FR > 90 rpm, TFr around 46 °C and TFl up to 44.7 °C, reflecting increased dissipation effort through hyperventilation and peripheral vasodilation. Adult categories showed the largest increases, while young animals presented more moderate responses, suggesting better thermal recovery. The results confirm a positive association between ITHaj and physiological variables, evidencing that the thermal environment is the main determinant of the physiological response of Charolais cattle in summer. TFl stood out as a sensitive surface indicator of the degree of stress. In conclusion, there is individual variability that can be exploited for the selection of more resilient animals, and it is important to integrate ITHaj with physiological measurements for welfare monitoring and adaptive management in subtropical pastoral systems.

Evaluación del comportamiento de vaquillonas de carne en sistemas silvopastoriles

Antonia Díaz Pastorino — 2025-12-05

Silvopastoral systems (SSP) have gained increasing interest in recent years due to the expansion of forestry in Uruguay and the potential benefits for animal production. In order to explore the differences between traditional rearing systems and a silvopastoral scheme, the impact of incorporating low-density trees on behavior (grazing vs. resting; lying down/standing) and its relationship with individual feed efficiency, this study with beef heifers was conducted on a commercial farm (Cerro Largo, Uruguay) during February 2025. Thirty-six Brangus heifers (18 months of age, 336±66 kg BW at the start of the measurement period) were used, randomly assigned to a complete block design and three treatments: a Control without trees, two rows of trees (2F), and four rows of trees (4F) with three repetitions (4 cows/treatment/block). The spatial arrangement consisted of distances of 5 meters between trees within the row, and 5 meters between adjacent rows, (5x5 layout). These rows (double or quadruple) were separated by 20-meter alleys, which determined a density of 160 trees/hectare for 2F, and 240 trees/ha for 4F. For 8 days, posture (standing/lying down) and activity (grazing/non-grazing) were evaluated using three-axis accelerometers (HOBO pendant G data logger, Onset Corp., MA, USA), placed on the medial face of the left hind leg and on muzzles, respectively. The recordings from both accelerometers, taken every 1 minute, were unified to define three distinct activities for the heifers: grazing, resting + rumination standing, and resting + rumination lying down. The data were analyzed using mixed models with repeated measures, and the effect of the temperature - humidity index (THI) on behavior was evaluated by multiple linear regression, with THI considered a continuous variable. Patterns dictated by the circadian rhythm regarding animal behavior were evidenced, with more important grazing events at dawn and dusk, and minimal nocturnal grazing activity with a preference for the lying down posture during the night. In turn, increases in ITH were associated with reductions in grazing time, which were explained by an increase in the number of sessions and decrease in their duration in the 4F treatment. Heifers in SSP (2F and 4F) had a greater daily resting + rumination lying down time, while no differences were found in the time dedicated to grazing. However, the forage intake rate (g DM/min) was higher in the Control heifers, which also exhibited greater grazing time during midday and nighttime hours. In turn, there was a preference for standing in the Control heifers, and the proportion of lying down time out of the total non-grazing time increased with ITH during daylight hours only in the SSP. These results would suggest greater animal welfare in the SSP, which could be attributed to the microclimate generated by the presence of trees. Individual feed efficiency measured as residual heat production (RHP) of the heifers was positively correlated with the forage intake rate, but not with other grazing or postural behavior variables. In conclusion, the inclusion of trees in a low density caused modifications in the heifers' behavior, which reflected greater thermal comfort, favoring animal welfare, without large differences between the distinct tree densities.

Evaluación de eficiencia alimenticia en vaquillonas de carne en sistemas silvopastoriles

Clara Giribaldi Carriquiry — 2025-12-04

In the current context of climate change and increasing food demand, the development of sustainable and efficient livestock systems becomes essential. Silvopastoral systems (SPS) have emerged as an alternative due to their environmental, productive, and economic benefits. To evaluate the effect of the absence or presence of trees at different densities on the partitioning of consumed energy between maintenance and production, we quantified productivity variables (body weight, BW; average daily gain, ADG; and subcutaneous fat thickness), intake variables (dry matter intake, DMI; digestible organic matter, DOM; and metabolizable energy intake, MEI), and the use of consumed energy (energy retained in tissues, RE-tissue; heat production, HP; RE-tissue/MEI; RE-tissue/HP; residual heat production, RHP) in 36 Brangus and crossbred heifers (18 months, 349 ± 12 kg BW). Animals were randomly assigned to a randomized complete block design with three treatments: control without trees (CON), two tree rows (2R), and four tree rows (4R), with three replicates (4 heifers/treatment/block). The spatial arrangement in both tree treatments (2R, 4R) consisted of 5 x 5 + 20 meters. The experimental period lasted 15 days and took place over the summer. Heat production was determined using the heart rate (HR)–O₂ pulse technique, and forage OM digestibility was estimated from fecal N in samples collected during the trial. The MEI was estimated as HP + RE-tissue, and DMI was derived from MEI and forage ME concentration. Data were analyzed using mixed models, and means were considered different when P < 0.05. No differences were observed among treatments in ADG (156 ± 5 g/d) or RE-tissue (243 ± 3 kJ/kg BW0.75/d). Heart rate and O₂ pulse did not differ among treatments (75 ± 1.8 beats/min and 0.279 ± 0.013 µL O2/BW0.75/beat), but average HP was higher in CON than in 2R and 4R (668, 592, and 573 ± 34 kJ/kg BW0.75, respectively). Moreover, HR and HP varied over the day and there was a significant treatment x time interaction, showing minimum values at night (21:00–5:00 h) and peaks at the beginning and end of the day (6:00–9:00 h and 17:00–19:00 h). These patterns were more pronounced in CON heifers, which also showed higher midday values (11:00–13:00 h). The DMI, DOM intake, and MEI were higher in CON heifers compared with 2R and 4R (9.2, 7.9, and 7.9 ± 0.4 kg/d; 4.0, 4.5, and 4.5 ± 0.42 kg/d; and 72,6, 58,1, and 60,6 ± 2.8 MJ/d, respectively). However, when expressed as %BW or BW0.75, no differences in DMI were detected, although CON heifers showed 16% greater DOM intake and MEI, reflecting the higher forage OM digestibility in CON compared with 2R and 4R. Despite no differences in feed conversion (20.4 g/kg DM), the efficiency of ME use, expressed as RE-tissue/MEI and RE-tissue/HP, was lower, while RHP was higher in CON than in 2R and 4R (RHP of 4.77, –2.69, and –2.71 ± 2.57 MJ/d, respectively). These results suggest lower maintenance energy requirements in SPS, with no major differences between tree-density treatments. The greater partitioning of ME toward production in SPS was likely associated with reduced activity and thermoregulation costs resulting from a more favorable microclimate.

Evaluación del dron como tecnología de aplicación de herbicidas

Facundo dos Santos Bianchi — 2025-12-02

The use of drones in agriculture has increased exponentially in recent years, driven by advances in precision agriculture and by the operational advantages they offer over ground applications, especially under limited field access conditions. However, there is still limited information regarding their efficiency in pesticide applications and how operational variables affect spray deposition and weed control. This study aimed to evaluate the effectiveness of glufosinate ammonium applied with a DJI Agras T40 drone under different configurations of spray volume (8 L/ha and 16 L/ha) and droplet size (medium: 250µm and coarse: 500µm) in two vegetation conditions: a Dactylis glomerata pasture and Avena sativa crop. The experiments were conducted at INIA La Estanzuela Station (Colonia, Uruguay) using a randomized strip design, with continuous recording of climatic variables. Spray recovery was assessed using water-sensitive cards and Petri dishes, with the concentration of a fluorescent tracer (Tinopal) measured. In addition, deposition on plants was quantified through the measurement of the same tracer (Tinopal) using a spectrofluorymetry, and weed control efficiency was evaluated through visual assessment and NDVI analysis obtained by a multispectral drone. Results showed that the application volume was the most determining factor for both deposition and control, with significantly higher effectiveness at 16 L/ha compared to 8 L/ha. Droplet size also played a key role, with coarse droplets (500µm) resulting in greater recovery and deposition, associated with a lower proportion of driftable droplets and higher flight stability. Although spray volume did not significantly affect recovery, a positive trend was observed at higher volumes. In terms of deposition, a significant interaction between droplet size and volume was detected in D. glomerata, where the combination of higher volume and coarse droplets produced the highest Tinopal recovery. Regarding weed control, treatments with 16 L/ha achieved greater control levels, consistent with the differences observed in deposition and reflected in NDVI measurements. In summary, the spray volume was the most influential variable in the effectiveness of glufosinate applied by drone, while droplet size complemented its effect by improving product deposition on target. These results confirm the potential of drones as a viable tool for herbicide applications provided that operational parameters are properly selected, contributing to greater efficiency, reduced environmental impact and enhanced sustainability in agricultural practices.

Efectos alelopáticos de rastrojos de cultivos de servicio en la supresión de malezas problemáticas

Alessandro Malan Sanin — 2025-12-01

The present study aimed to evaluate the allelopathic potential of residues from three cover crops Avena strigosa (black oat), Secale cereale (rye), and Vicia villosa (hairy vetch) in the suppression of the weeds Amaranthus palmeri (Palmer amaranth), Echinochloa colona (jungle rice. Bioassays were conducted under controlled conditions using aqueous extracts obtained from the aerial and root parts of each species. Results showed that oat exhibited the highest inhibitory capacity on both weed species and Lactuca sativa used as an indicator species, with significant reductions in root and hypocotyl length, in some cases even surpassing the herbicide control. Vicia villosa also showed a reduction effect, particularly on A. palmeri, with root extracts standing out for their activity at low concentrations. Secale cereale, in turn, displayed a strong allelopathic potential on the indicator species (L. sativa), although it had a lower effect on A. palmer iand no effect on E. colona. The results confirm that these cover crops mainly oat contain compounds with inhibitory capacity that could contribute to weed suppression, complementing the physical effect of crop residues within integrated weed management. Further field studies are needed to determine whether these laboratory findings can be reproduced under real production conditions.

Evaluación de la tecnología de aplicación con drones en el control de malezas

Ignacio Fischer Gutierrez-Zorrilla — 2025-11-21

Technological advances in agriculture have enabled the development of new tools that seek to optimize pesticide applications and improve the efficiency of weed control. Among these, the incorporation of agricultural drones represents a recent innovation that offers operational advantages over traditional ground and aerial equipment, such as the ability to work in limited soils, reduced infrastructure requirements, and greater application precision. The objective of this study was to evaluate different drone application technologies for weed control efficiency in herbicide application situations in fallow land and in a wheat crop. To this end, two experiments were conducted at the Mario A. Cassinoni Experimental Station (EEMAC) of the Faculty of Agronomy. The treatments consisted of a combination of two application volumes (10 and 20 L/ha) and two droplet sizes (350 and 500 μm), applied with a DJI Agras T40 drone. In each experiment, four treatments were evaluated, analyzing application quality parameters using water-sensitive cards and controlling efficacy against different weed species. The results showed that, under favorable weather conditions, no significant differences in weed control efficacy were observed between treatments, with excellent levels of control achieved for all species evaluated in fallow land. In wheat, although droplet volume and size did not generally determine efficacy, differential responses were observed in Raphanus raphanistrum and Coronopus didymus. Differential performance was observed in R. raphanistrum for the 10 L/ha and 500 μm treatments, while in C. didymus only the 20 L/ha treatments achieved excellent levels. Regarding droplet deposition, treatments with 350 μm droplets achieved higher impact densities and better coverage, albeit with greater variability, while 500 μm droplets showed more uniform distribution but lower coverage. Overall, the results indicate that drone-assisted herbicide application achieves high levels of weed control efficacy with reduced volumes, representing an efficient and sustainable alternative for weed management.

Alternativas vitícolas y enológicas para la reducción del contenido de alcohol y pH en los vinos tintos Tannat

Yamila Celio Ackermann — 2025-11-21

Uruguay is characterized by high interannual climate variability, expressed in fluctuations in temperature and rainfall that directly impact vineyard development and grape ripening. High temperatures and periods of drought have accelerated ripening processes, producing wines with higher alcohol content and pH, but with incomplete phenolic and aromatic profiles. This situation forces the period to be extended, making it difficult to determine the optimal time for harvesting. The objective of this research was to evaluate the impact of pre apical leaf removal and the partial replacement of ripe must with must or wine from unripe grapes on reducing the alcohol content and pH of Tannat red wine, without modifying its phenolic composition and colour. The study was conducted during the 2025 harvest in a commercial vineyard in southern Uruguay. Six groups of ten plants were studied, three of which underwent pre-apical leaf removal at the beginning of veraison (E-L 36) by manually removing leaves from the seven nodes above the second cluster, while the other three groups were left as controls without leaf removal. The canopy structure, yield and evolution of grape composition were evaluated until harvest. Wines were produced in triplicate for the following treatments: VT (control, traditional vinification), VD (pre apical leaf removal), VSM (replacement of 20% of ripe must with unripe grape must) and VSV (replacement of 20% of ripe must with unripe grape wine). The physicochemical parameters, phenolic composition, colour and sensory characteristics of each wine were determined by a panel of tasters. The results showed that pre apical leaf removal reduced the leaf area without affecting yield. This technique influenced the accumulation of sugars in the berries, allowing the production of wines with lower alcohol content. The most relevant differences in phenolic composition were observed in the wines, with reductions of more than 15% compared to VT, also affecting colour. The VSM and VSV treatments succeeded in reducing alcohol content and pH. The variations in phenolic composition did not exceed 10% compared to the control. No sensory differences were found between the wines, except in terms of appearance. The tasters showed a greater preference for wines from the VD and VSV treatments. In conclusion, both the viticultural and oenological strategies evaluated represent viable alternatives to produce wines with lower alcohol content. The impact on colour and phenolic composition will depend on the climatic conditions of each harvest, so their application must be adapted to the agroclimatic context of each year.

Efecto del método del pastoreo y la oferta de forraje sobre la productividad del campo natural

Joaquin Reboledo Sobredo — 2025-11-20

This work was carried out at the Mario A. Cassinoni Experimental Station, part of the Faculty of Agronomy of the University of the Republic. It is located at kilometer 363 of Route 3, in the department of Paysandú. The work was conducted in Paddock 13 of the facility, covering an area of 37.8 hectares of natural land. The experimental modality consisted of four treatments, each carried out in a subdivision of the same pasture. Two of them were under continuous grazing, while the remaining two were under rotational grazing. The latter two, in turn, consisted of 14 plots of 0.6 hectares each. In addition, one continuous grazing treatment and one rotational grazing treatment were selected, which were managed at high stocking rates, while the remaining two were managed at low stocking rates. The animals used were Holando steers. FO levels are adjusted monthly based on forage availability (kg DM/ha) and expected growth rates, regulating stocking rates based on monthly weighing data. The evaluation period ran from July 24 to October 30. The objectives of the study were to evaluate both primary and secondary production under the influence of grazing methods and stocking rate adjustments, as well as to characterize the vegetation cover associated with the different soil types present in the pasture. For this purpose, a characterization carried out by students was used as a reference, based on the soil types present in the pastures: Low, Medium, and Lithosol. The variables studied were forage height (cm) and mass (kg DM/ha), botanical composition, and average daily animal gain (kg LW/ha). Results were analyzed using ANOVAs, and means were compared using the statistical software Infostat with significance levels of 5% and 10%. Four hypotheses were proposed, examining the effects of grazing method, forage supply, soil type, and study period as independent variables. After analyzing the results, it was concluded that all of the aforementioned variables had a significant impact on the results obtained.

Caracterización de aislados y evaluación de curasemillas para el control de Leptosphaeria maculans en colza

Virginia Mutay Luzardo — 2025-11-07

The objective of this study was to characterize the aggressiveness of seven Phoma lingam isolates on the canola cultivar Rivette, as well as to evaluate the effect of different seed dressings for preventive disease control in seedlings. Canola is a crop of growing importance in Uruguay, and the disease known as blackleg, caused by the fungus Leptosphaeria maculans (anamorph Phoma lingam), represents a significant threat to its establishment and productivity. The trials were conducted under controlled conditions at the INIA La Estanzuela experimental station in Colonia, Uruguay, using a completely randomized block design with three replicates per treatment. For isolate characterization, seven Phoma strains collected from different locations and years were tested, using a pot with 6 to 10 Rivette plants as the experimental unit. Plants were inoculated at the cotyledon stage with a spore suspension (1×10⁷ spores/mL), and disease severity was measured ten days post-inoculation using a 0-to-9 scale, where 0 indicates the absence of symptoms and 9 represents severe cotyledon lesions. The results showed significant variability in aggressiveness among the isolates. In the first trial, isolate Ph031 exhibited the highest severity, while Ph021 and Ph033 were the least aggressive. In the second trial, the most virulent isolate was Ph026, and the least aggressive was Ph022. These differences reflect the genetic and phenotypic diversity of the pathogen, highlighting the importance of its characterization for effective disease management. For the seed dressing evaluation, various chemicals and biological products were used, including Fluopyram (Fluoram), Zentro, and a biological product (Lalstop), applied at different doses. The isolate used in this phase was Ph042, collected from the same Rivette cultivar. Results showed that treatments with Fluopyram, even at the lowest dose of 150 g a.i/ 100kg seed, achieved complete suppression of symptoms in both trials, while the remaining treatments exhibited varying levels of severity. In conclusion, variability in aggressiveness was identified among Phoma isolates, and the use of Fluopyram as a seed treatment at a low dose proved to be highly effective in preventing early-stage infection. These findings provide valuable tools for the integrated management of blackleg, particularly during crop establishment, and open the possibility of reducing or delaying subsequent foliar fungicide applications. Although the trials were conducted under controlled conditions, field evaluations are recommended to validate these results under real-world production scenarios

Vinificación de mínima intervención

Alejandro Cammarota Tain — 2025-10-30

Sulfur dioxide is one of the most widely used additives in the food industry due to its antimicrobial and antioxidant properties. In winemaking, it is the most widely used additive due to its ability to inhibit the growth of undesirable microorganisms and prevent oxidative changes. However, it has been classified as slightly toxic, negatively affecting the health of 1% of consumers and causing reactions such as bronchospasm, bradycardia, urticaria, angioedema, hypotension, diarrhea, dermatitis, and anaphylactic reactions. Wine is one of the main sources of sulfite intake in adults, often exceeding acceptable daily levels. In this context, winemakers have responded to these concerns by adopting more sustainable and safer production strategies, minimizing negative impacts, with the aim of producing safe products that are in line with contemporary market demand, without compromising the quality of the final product. This study evaluated alternatives to reduce or replace the added sulfite content in wines from the Marselan, Merlot, and Tannat cultivars, produced with minimal intervention during the 2024 harvest. The fermentation kinetics, microbiological, physicochemical, phenolic, and colorimetric composition of the wines were analyzed. The minimal intervention treatments were vinified without the addition of yeasts, with Q being the addition of chitosan (100 mg/L), SO₂R corresponds to a reduction in added sulfites (30 mg/L), SO₂R+Q is a combination of the above treatments, and a control treatment (VT) with conventional addition of sulfur dioxide (125 mg/L) and inoculation of selected yeasts. Microbiological counts showed that, in Marselan and Merlot, the control wines had a lower yeast population than the minimal intervention treatments, with no significant differences in lactic acid bacteria. In Tannat, the control treatment showed lower counts of these bacteria, with no differences in the yeast population. Fermentation kinetics were slower in the minimal intervention musts compared to the control treatment. The chitosan treatment showed the highest color intensity in all three cultivars. In terms of phenolic composition, SO₂R and VT showed the highest concentrations in Marselan and Merlot, while in Tannat, the highest values were observed in Q and SO₂R+Q. Sensory analysis in Merlot showed no differences between treatments. In Tannat, the Q and SO₂R wines obtained the same preference as the control. At Marselan, sensory evaluation was not performed due to the general condition of the wine, highlighting the importance of the health and quality of the raw material. This work provides technical evidence on the impact of minimal intervention strategies on the microbiological stability and oenological composition of wine, and represents a contribution to the search for more sustainable practices in contemporary viticulture.

Variabilidad genotípica y ambiental de parámetros morfológicos del grano de cebada cervecera (Hordeum vulgare L.) y su relación con parámetros de calidad maltera

Noelia Vera Siri — 2025-10-27

Barley in Uruguay is the second most widely grown winter crop, and its main use is for malting, primarily for export. Malting quality is a key factor in its suitability for brewing. Understanding how malting quality parameters vary and how they are influenced is important for the efficient development of new cultivars. The main objective of this study was to evaluate the relationship between barley grain morphological parameters and fine extract, a malting quality parameter. Morphological parameters were measured in commercial cultivars and advanced lines from the INIA Breeding Program to determine whether barley grain morphological parameters (width, length, A_L ratio, perimeter, area, color) could serve as indicators of malting quality in earlier generations of the breeding program. Finally, the predictive power of these variables was assessed, validating their usefulness using independent phenotypic data from F7 lines obtained in preliminary trials. The Advanced and Elite trials were planted in the INIA Barley Breeding Program in 2023 using a randomized incomplete block design with two replications. The variables evaluated were 1000-seed weight, grain classification, morphometry, and malting quality for each sample. For malting quality analysis, the samples were micro-malted by the Uruguayan Technological Laboratory (LATU). Analysis of variance for the different variables was performed using mixed models, incorporating spatial analysis of the trials. For estimating fine extract, a multiple linear regression model with stepwise variable selection was used. The variance values for yield, in both the Elite and Advanced trials, showed that most of the observed variability was explained by environmental effects. In contrast, the variables 1000-seed weight, grain classification, and morphometric parameters showed that the main source of variation was the genotypic effect. Regarding the correlations between morphometric parameters and malting quality, it was observed that seed size classification and 1000-seed weight showed a positive correlation, and grain width also demonstrated a positive correlation with both variables. The correlation between grain protein content and extract yield was negative in the trials evaluated. Among the regression models, the equations corresponding to the elite and preliminary trials were the most significant. Finally, among the models used to predict extract yield in Preliminary trials, the equation developed from the Elite trials was the most accurate, due to a higher coefficient of determination. This equation included grain protein content, grain width, and grain length as predictor variables. Therefore, determining parameters such as grain width, grain length, and grain protein content in an experimental line would allow for an estimation of malting quality in earlier generations of breeding programs, through a simpler measurement and without the need for pre-selection based on other characteristics.

Efecto de la fertilización nitrogenada e incorporación de leguminosas sobre la productividad y composición botánica de un campo natural

José Ignacio Aguiar Calero — 2025-10-10

This work was carried out in pasture 18 of the Mario A. Cassinoni Experimental Station (EEMAC) at the Faculty of Agronomy, University of the Republic. It is located on National Route No. 3, General Brigadier José Gervasio Artigas, km 363, Paysandú Department, Uruguay (32º 20' 9'' South latitude and 58º West longitude, 61 m above sea level). The evaluation period was from June 8, 2015, to February 9, 2016, and it was divided into three periods: winter, from June 8, 2015, to October 1, 2015; spring, from October 1, 2015, to December 18, 2015; and summer, from December 18, 2015, to February 9, 2016. The objective of the study was to evaluate dry matter production and changes in the botanical composition of a natural pasture subjected to different levels of intervention, under grazing by steers with a forage offer ranging between 8% and 10% of live weight. The experimental design was a completely randomized block design with four treatments. These included a control without intervention (CN), a treatment improved by the incorporation of Lotus tenuis and Trifolium pratense with a fertilization of 40 kg per hectare of P2O5 (CNM), and two treatments with the same phosphorus fertilization of 40 kg P2O5 per hectare but different nitrogen doses: one with 60 kg nitrogen per hectare (60N) and the other with 120 kg nitrogen per hectare (120N). The studied variables included: dry matter production (PROD), available dry matter (MSDISP), percentage of available green dry matter (%MSDISPV), percentage of available dry matter remains (%MSDISPRS), daily growth rate (TC), disappeared dry matter (MSDESP), percentage of disappeared forage (%DESP), available height (ALTDISP), remaining dry matter (MSREM), remaining height (ALTREM), percentage of remaining green dry matter (%MSRSV), and percentage of remaining dry matter remains (%MSREMRS). The botanical composition analysis studied the following variables: percentage of green dry matter (%MSV), percentage of dry matter remains (%MSRS), percentage of winter perennial grasses (%GPI), percentage of summer perennial grasses (%GPE), percentage of winter annual grasses (%GAI), percentage of herbs (%HIERB), percentage of legumes (%LEG), and percentage of thistles (%CARD). The results indicate that nitrogen fertilization, both at 60 kg and 120 kg per hectare, significantly increased dry matter production in winter and spring, leading to a greater amount of disappeared forage. Additionally, the treatment improved with legumes increased dry matter production during the summer period compared to the non-intervention treatment. Regarding the botanical composition, a higher presence of legumes was observed in the improved natural pasture treatment (CNM). The study also showed the seasonal variation of the botanical components: in winter, winter perennial grasses, herbs, and thistles increased, while in spring, summer perennial grasses and legumes increased. Furthermore, spring showed a higher proportion of green forage compared to winter.

Evaluación de microorganismos eficientes nativos (MEN) en el control de tizones en el cultivo de papa (Solanum tuberosum L.)

Guillermo Paroli Mislej — 2025-10-10

Potato is the most important vegetable crop in Uruguay in terms of gross production value and per capita consumption. It is affected by several diseases, among which late blight (Phytophthora infestans) and early blight (Alternaria spp.) are the most important, as they cause severe economic losses. Frequent agrochemical applications are used for their control, which have negative impacts on the environment and human health.

The objective of this thesis was to determine the effectiveness of applying MEN (Native Efficient Microorganisms) to control foliar diseases in potato crops.

The experiment was conducted at the South Regional Centre (CRS) of the Facultad de Agronomía, Universidad de la República, in an open-field crop using the INIA Arequita variety. Four treatments were applied: MEN 10% (T1), MEN 15% (T2), MEN 10% + agrochemicals when weather conditions favored the epidemic (T3), and a control plot (T0) sprayed with water. All treatments were applied to the foliage.

The results showed that MEN application was effective in reducing both diseases at the beginning of the epidemic. The treatment combining fungicides with MEN achieved the greatest reduction and produced tuber weights on average 30% higher than the control plot. Although further studies are necessary, these results suggest that MEN application could be incorporated into an integrated disease management strategy for late and early blight.

Efecto del volumen de rastrojo remanente en el logro de resiembra de raigrás

Rafael de la Rosa Pereira — 2025-10-06

This study addresses the dynamics of natural reseeding of annual ryegrass (Lolium multiflorum Lam.), focusing on the effect of summer fallow management through different levels of crop residue. The importance of this topic lies in optimizing ryegrass establishment via the seed bank, thus reducing costs and improving system sustainability.

The main objective was to evaluate whether the amount of residue left on the soil surface affects final plant establishment, to understand how it modifies environmental conditions (temperature, moisture, and radiation) during summer, and how this, in turn, influences seed dormancy dynamics, germination, and plant establishment from the seed bank.
The experiment was conducted from December 5, 2022, to April 3, 2023, at the INIA Glencoe Experimental Unit, located in the department of Paysandú (Latitude 32.02°S; Longitude 57.16°W). Sample processing was carried out at the Pasture Laboratory of INIA Tacuarembó (Route 5, km 386). A randomized complete block design (RCBD) was used, with four blocks and four treatments, resulting 16 experimental units (rectangular plots measuring 2 x 5.5 meters). Soil variables were measured (temperature at 1 cm and 3.5 cm depth, moisture at 3.5 cm and 20 cm), as well as intercepted radiation, seed dormancy status over time, final establishment percentage, and biomass production.

Results showed that higher residue levels created a moister and cooler surface environment, with greater interception of photosynthetically active radiation. Despite significant differences in soil temperature and moisture among treatments, no effects on the progression of seed dormancy were observed. Regardless of these environmental variations, the seed bank remained largely conserved until early March. In terms of germination, treatments with higher residue levels promoted earlier emergence, although this did not result in significant differences in the final number of established plants.

It is concluded that summer residue management alters soil conditions and may advance germination timing, but does not significantly affect autumn plant density. Therefore, under the evaluated conditions, residue volume did not result in clear agronomic advantages for ryegrass reseeding.

Caracterización de la colección ex situ de Phaseolus Lunatus L. y Phaseolus vulgaris L. conservados en el banco de germoplasma de la Facultad de Agronomía-Udelar

Ian Tadich Delascio — 2025-09-26

The species Phaseolus lunatus L. and Phaseolus vulgaris L. (common bean) are the most widely cultivated species of the Phaseolus genus in Uruguay. Their production is based on landraces, and today there are no cultivars registered in the National Registry of the National Seed Institute (INASE). Data from the General Agricultural Census confirm that the number of farmers or peasants has decreased, as has the beans cultivated area, evidencing a progressive loss of family production systems and, with them, the associated genetic diversity. This situation highlights the need to conserve and enhance the available plant genetic resources preserved in ex situ collections. In this sense, and considering that the existing collections in the Germplasm Bank of the Faculty of Agronomy were not characterized and did not have complete passport data, it was proposed to advance the characterization and multiplication of these accessions as a strategy for their conservation and sustainable use. The objective of this work was to evaluate the existing diversity in seven accessions of Phaseolus lunatus L. and 18 accessions of Phaseolus vulgaris L. collected by the Horticulture Department in 1985/1986. The characterization was carried out at the Faculty of Agronomy, Sayago, Montevideo-Uruguay, between November 2022 and June 2023. Phenotypic descriptors of plants, flowers, and grains, extracted from the International Plant Genetic Resources Institute (IPGRI) descriptor guides for each of the species, were evaluated. It is shown that for P. vulgaris and P. lunatus, within the species, all accessions differ from each other by at least one characteristic (descriptor). Diversity was identified in the collection of both species. For P. lunatus, seven of the sixteen descriptors used were discriminant. For P. vulgaris, fourteen of the fifteen descriptors were discriminant. This work allowed us to characterize diversity, which will guide future agronomic evaluation work on native bean varieties and expand knowledge of the Germplasm Bank's collection.

Efecto de diferentes estrategias de alimentación sobre las variables biofísicas, en dos sistemas lecheros de base pastoril, con cargas animales contrastantes, durante el verano

Ximena Burgueño Navarro — 2025-09-26

Dairy farming is the sector with the highest income per hectare (ha). Although annual production in millions of liters has not changed significantly over the last decade, the country's dairy herd has declined, with a loss of farms and total farmed area, and a consequent increase in the stocking rate of the systems. The objective of this study was to compare a high-productivity (HP) system with an average stocking rate in the grazing platform (GP) area of 2.7 milking cows per GP (MC/ha GP), aimed at achieving high milk productivity per ha, supplemented with concentrate, and with reserves produced outside the GP area. Another low-cost (LC) system with an average animal load of 1.6 MC/ha GP, with operational simplicity as a premise, self-sustaining from the fiber point of view with the entire reserve produced in the GP area, where the animals were supplemented with concentrate and with reserves (produced in the GP area). Both systems were managed with the same forage model, a 6-year perennial rotation without summer greening (SG). Grazing criteria were based on forage stock control and weekly growth rate (GR). The work was carried out at the Dairy Unit of the Southern Regional Center (CRS), in the department of Canelones (Uruguay), between December 21, 2021, and March 21, 2022. The systems did not show significant differences in forage intake by direct harvest (with differences in grazing opportunities), reserves, and concentrate per hectare. The systems differed in forage production, but these differences did not translate into forage intake per LC. The systems did not differ in milk production per milking cow (MC), but they did differ in milk and solids production per ha GP. Feed margins per MC were higher in the LC system, while better margins per surface area were achieved with the HP system.

Efecto de la secuencia de cultivos invernales sobre la dinámica de malezas invernales

Laura Rovetta Olivares — 2025-09-15

Weeds represent one of the main constraints to efficient agricultural production, affecting crop yields through their abundance, composition and interference. The growing problem of resistance to chemical control tools by weeds highlights the need to study tools that implement Integrated Weed Management. Within these strategies, crop sequence planning is key, since it allows diversifying associated technologies affecting the biological processes of weeds. The aim of this final work was to study the effect of different winter crop sequences on winter weeds. In 2023 wheat, barley, canola and oats were established over each of the previous year's winter crops, resulting in a split-plot design within the previous year's DBCA. In this way, all possible winter combinations were evaluated, except wheat after wheat, barley after barley and wheat after barley (or vice versa), for sanitary reasons. Weed species, the number of plants per species, their stage of development and the percentage of cover occupied by weeds and crop were recorded monthly. The results showed significant differences in weed infestation among the different crop sequences, with an interaction between the 2022 preceding crop and the 2023 crop. At the end of the cycle, the cereal crops reduced the weed infestation, regardless of the predecessor on which they were sown, while the rapeseed crop did not achieve this effect in any of the sequences evaluated. This is explained by the characteristics of each crop and the different technologies available, such as chemical control, highlighting the importance of crop sequence within Integrated Weed Management.

Evaluación de fungicidas curasemillas para el control de Pyrenophora teres f. teres en cebada

Rocío Fernández Gay — 2025-09-12

Net blotch (NB), caused by Pyrenophora teres f. teres, represents a significant threat to barley production. Chemical seed treatment emerges as a key preventive strategy to limit its introduction and spread in crops. To evaluate the efficacy of five seed treatment fungicides in controlling NB during the initial stages of barley development, a field experiment was conducted using a randomized complete block design with four replicates. The cultivar Explorer, which has high to intermediate susceptibility, was used with an initial fungal load of 5%. The treatments consisted of the following active ingredient formulations for seed treatment: metalaxyl, penflufen, prothioconazole; fluxapiroxad + triticonazole; difenoconazole + fludioxonil + sedaxane + thiamethoxam; carbendazim + iprodione + thiram; azoxystrobin + iprodione + metalaxyl + triticonazole, along with an untreated control. The evaluated variables were percentage of plant emergence and disease incidence at 13 days post-emergence (DPE, growth stage Z1.3), and disease severity at 31 (Z2.2), 50 (Z3.0), and 73 DPE (Z4.3). From these, the area under the disease progress curve (AUDPC) and the percentage of control efficacy (%CE) were calculated. Weather conditions during the trial were highly conducive to MRtr development. No significant differences were observed among treatments for plant emergence or early disease incidence (13 DPE). At Z2.2, disease severity was high—approaching the critical threshold—but no significant differences were detected between treatments. However, significant differences emerged at Z3.0, where the mixtures containing fluxapiroxad + triticonazole and sedaxane + fludioxonil + difenoconazole + thiamethoxam exhibited the lowest severity levels. AUDPC analysis confirmed that these two combinations were the most effective in limiting NB progression, thus providing the best relative control under the specific trial conditions. However, the %CE of these treatments was to low, <50%, highlighting that under conditions of high inoculum pressure and favorable weather, seed treatment alone was insufficient to maintain disease levels below critical thresholds. This underscores the importance of integrating seed treatments with additional disease management strategies, emphasizing continuous monitoring and the responsible use of fungicides within an integrated disease management framework.

Evaluación del crecimiento radicular de portainjertos de la serie Geneva en manzano (Malus Domestica Borkh.) bajo condiciones del sur de Uruguay

Sebastián Acosta López — 2025-09-09

In modern fruit growing, production systems tend to be increasingly intensive, with higher planting densities that require the support of an appropriate technological package. This includes irrigation, fertilization, and specific training systems, with the aim of increasing production efficiency and optimizing labor use. For these systems, which involve a high initial investment, to be successful, it is essential to correctly select both the rootstock and the variety, as both directly influence the tree’s vigor, productivity, disease tolerance, and adaptation to environmental conditions.

The Geneva® rootstock series has gained international recognition for its agronomic and plant health performance, and its adoption is growing in Uruguay. In this context, the National Institute of Agricultural Research (INIA) has initiated trials to evaluate its local performance. This study evaluated the root growth of six clonal rootstocks from the Geneva® series (G.202, G.210, G.214, G.213, G.814, and G.41) under the soil and climate conditions of southern Uruguay. In a randomized complete block experimental design with 18 replicates, three quantitative variables associated with root development were measured: root length, volume, and area, using a root scanner (CI-600) and RootSnap software.

The results showed significant differences between rootstocks in all three variables evaluated. Rootstocks G.202 and G.210 stood out for presenting the highest root growth values and low variability between replicates, while G.213 showed the lowest growth and the greatest variability. In all cases, the highest proportion of roots was concentrated in the first 20 cm of the soil profile. These results provide key information for decision-making in the selection of rootstocks, considering their impact on tree vigor and the most appropriate training system, and contribute to the development of more efficient and sustainable fruit growing.

Efecto de la luz roja lejana en el enraizamiento de estacas provenientes de plantas madre de dos clones de Eucalyptus dunnii

Franco Martín Conde Morales — 2025-09-03

Currently, 1,085,000 hectares in the country are allocated to forestry use, with more than a quarter dedicated to the species Eucalyptus dunnii. Despite its good wood properties, rapid growth, and frost resistance, it is recalcitrant to rooting, which limits its clonal propagation. This study aimed to analyze how far-red light (FRL) supplementation in mother plants of E. dunnii influences the rooting of cuttings and shoot production. Adventitious rhizogenesis is primarily regulated by auxin and carbohydrate levels, which can be modulated by the mother plants growing environment. Recent studies have shown that light in the 700-800 nm range can promote adventitious rooting. Five variables were evaluated: the number of shoots produced per mother plant, rooting percentage, overall productivity, cutting survival and soluble carbohydrate and starch content at the base of the cuttings. For this purpose, 1.5-years-old mother plants of two Eucalyptus dunnii clones (Clone A and B) were grown in controlled-environment chambers, from which mini-cuttings were taken after one month of RL treatment. The results showed that RL supplementation affects overall productivity by modifying shoot production and rooting percentage. In clone B, the rooting percentage increased from 26% to 40%, representing a 52% increase, along with a 62% rise in shoot number. In contrast, Clone A showed no change in shoot production between treatments and experienced a 55% decrease in rooting percentage. This suggests that the treatment's success depends specifically on the genetic material used. Regarding survival, cuttings from RL treated plants had higher survival rates, indicating that a longer rooting period could influence the outcome. The carbohydrate content at the base of the cuttings at the time of cutting was not related to productivity, meaning this variable is not a reliable predictor of rooting under these conditions. The findings provide useful insights into managing light quality as a tool to improve performance in recalcitrant species within vegetative propagation systems.

Relaciones hídricas en dos clones de Eucalyptus en sistema silvopastoriles

Gonzalo Sebastián Pallas Rodríguez — 2025-09-01

This study analyzes the water behavior of two forest species of interest in a silvopastoral alley cropping system with tree rows oriented north–south and different spatial planting arrangements. Clones of Eucalyptus dunnii and E. grandis were evaluated, arranged in single rows and triple rows. In the triple row system, three crown exposure positions were considered: east external (EE), internal (I), and west external (EO), with the objective of characterizing physiological variations and their responses to the environmental conditions of the system.

The study was carried out at the Bernardo Rosengurtt Experimental Station (Cerro Largo, Uruguay) between February and August 2024. The physiological variables analyzed included predawn and xylem water potential, stomatal conductance, and the dendrometric parameters of height, diameter at breast height (DBH), and percentage of live crown. Measurements were taken in both winter and summer of 2024 to assess the influence of water availability on the ecophysiological performance of the clones.

E. grandis showed an average height of 4.84 meters and a DBH of 5.08 centimeters, which were 1.20 meters and 1.5 centimeters greater, respectively, than E. dunnii, particularly in trees located in the east and internal positions of the triple row. Meanwhile, E. dunnii exhibited a 10–15% higher percentage of live crown than E. grandis, due to its lower tendency for basal branch mortality. In terms of water potential, both species showed similar values, although the EE position had lower water potential due to greater exposure to solar radiation and prevailing winds, which significantly increased transpiration demand.

Stomatal conductance was 228 mmol m² s⁻¹ in E. grandis, especially during winter, reflecting a greater capacity for gas exchange under favorable moisture conditions. E. dunnii showed a more conservative water-use strategy with a conductance of 161.23 mmol m² s⁻¹, which could be advantageous under limited water availability. In addition, results indicated that the triple-row design showed better overall performance, maximizing growth and resource-use efficiency.

This study provides relevant information for the management of silvopastoral systems with Eucalyptus spp., offering tools to improve productivity and sustainability by understanding how growth and physiology of the forest component are influenced.

Caracterización productiva de terneros destetados precozmente con énfasis en el periodo de acostumbramiento

Nahuel Adrián Acosta Ocampo — 2025-08-29

This research was conducted at the Experimental Station Mario A. Cassinoni, at the beef cattle production unit (UPIC) from January 4th to March 16th, 2024. The objective was to identify and analyze the main factors affecting average daily gain (ADG) in early-weaned calves, with emphasis on the adaptation period. A total of 181 spring-born Hereford calves were evaluated and divided into two groups based on age and weight. The first group was managed under a feedlot early weaning protocol (DPC), while the second group followed a pasture-based early weaning protocol (DPP). Variables such as age, weight, health status, dam age, sex, dry matter intake (DMI), and feed to gain ratio (FG) were assessed using the Stepwise method. During the adaptation period (12 days), the DPC group showed an average ADG of 0.479 ± 0.33 kg/day. Health status had a significant effect (p = 0.0775), with a 17.8% reduction in ADG in the sick calves group compared to the healthy ones (0.473 vs. 0.576 kg/day). Age of the dam was also significant (p < 0.0001), showing an effect linked to calving season and calf age (p = 0.0002). Initial weight also had a significant but marginal effect on ADG (p = 0.0948), while sex showed no significant influence. Average DMI was 1.49 kg DM/animal/day, with a FG of 3.11. By day 8, 95% of the calves had adapted to the feeding system. After the adaptation period, DPC calves achieved an ADG of 1.45 kg/day with an average intake of 2.97 kg DM/day and a FG of 2.64. In the DPP group, the adaptation phase achieved an ADG of 0.453 ± 0.25 kg/day, with 1.23 kg DM/day of DMI and a FG of 2.7. No significant influencing factors were identified in this group, likely due to the lower incidence of illness and a less stressful environment. Calves' adaptation to the feeders occurred earlier in time (days 4–5). After the adaptation period, DPP calves grazed a pasture with an 8% BW forage allowance (2984.7 kg DM/ha and a stocking rate of 13 calves/ha) and received a ration supplementation (1% BW), achieving an ADG of 0.71 kg/day with 1.08 kg DM/day ration intake, resulting in a supplement FG of 2.32. The technical coefficients obtained were consistent with those reported in similar feeding systems, confirming their reliability. In the bioeconomic analysis, assuming a calf price of 2.23 USD/kg and a feed cost of 0.38 USD/kg as-fed, the DPC system yielded a gross margin 35.57 USD higher than the DPP system. Results indicate that calf health status and age significantly influenced ADG during the adaptation period. Both systems proved viable, with DPC standing out for its higher economic margin under the evaluated conditions.

Producción de leche y sólidos de vacas manejadas en sistemas pastoriles con distinta época de parto

Mauricio Gabriel Baridon Pons — 2025-08-29

This study analyzes the effect of calving season on milk production and composition in cows managed in pasture-based systems in Uruguay. The experiment was conducted at the INIA La Estanzuela Experimental Station with 60 New Zealand–origin Holstein cows, randomly assigned to three treatments of 20 cows each: autumn-concentrated calving (OTO), winter-concentrated calving (INV), and an extended calving period (EXT) covering both seasons. Productive, nutritional, and climatic variables were recorded using automated measurement technologies, milk compositional analysis, and forage management evaluation. The hypothesis proposed that individual milk and solids production would be similar in cows calving in winter and autumn, and higher than that of cows with an extended calving period in autumn and winter. Methodologically, a completely randomized design was employed, with appropriate statistical analyses to compare treatments. Results showed that individual milk production did not differ significantly among treatments, although the INV lactation curve exhibited a sharper decline after peak production. Milk composition in OTO revealed higher fat and protein concentrations (4% and 6% higher, respectively) compared to INV and EXT. Average body condition was 0.12 units higher in OTO and EXT relative to INV, which could be related to differences in forage supply and climatic impact. The study also revealed differences in forage availability and supplement use among treatments. INV benefited from a higher share of fresh pasture in the diet (57%) during mid-lactation, whereas OTO and EXT required greater contributions from silage (33% and 16%, respectively) and concentrates (32.8% and 31.6%). Climatic conditions influenced productive responses, particularly in EXT, which experienced more days of elevated heat stress. In the discussion, the results are interpreted in light of previous studies, analyzing the implications of calving season on productive efficiency and forage resource management in pasture-based systems. This study provides valuable insights for planning calving seasons in pasture-based dairy systems, highlighting that autumn-concentrated calving may improve milk composition without affecting individual production, and emphasizing the importance of further research to optimize these systems under Uruguayan conditions.

Respuesta agronómica y enológica de la variedad Albariño (Vitis vinifera L.) en distintas condiciones agroecológicas

Analía Verónica Hernández Carballido — 2025-08-29

The Albariño variety (Vitis vinifera L.) increased its surface area in the country by 224% between 2019 and 2024, positioning itself as the second most planted variety for the production of preferential quality wines. Understanding the general characteristics of the variety and its response to environmental conditions is useful for implementing site-specific management and product differentiation. The main objective of this work is to contribute to the agronomic and oenological characterization of Albariño in relation to the mesoclimate. The hypotheses presented are the topographic conditions of the study region as an influential factor in plot temperature (mesoclimate), and the impact of the geographical peculiarities of the plots (altitude and slope) on the agronomic and oenological potential of the variety through the mesoclimate. The study was carried out during the 2023-2024 season in a commercial vineyard near to Pueblo Garzón, in the department of Maldonado. For this work, six plots were selected under different topographic conditions (79, 89, 95, 120, 138, and 142 meters above sea level) and characterized mesoclimatically by recording temperature, thermal amplitude, Heliothermal Index, Degree Days, and Night Coolness Index. For the agronomic evaluation, yield, bunch weight, number of bunches per plant, potential exposed leaf area, pruning weight, Ravaz Index, and berry physical composition were measured. Oenological potential was determined by analyzing total acidity, soluble solids, pH, malic acid, tartaric acid, and alpha amino nitrogen (αAN), and ammonia and phenolic potential. Musts from the three lowest and three highest plots were vinified together, and their malic acid, ethanol, total acidity, pH, total polyphenol index (TPI), color intensity (420 nm), and volatile acidity content were evaluated. The results show that the altitude of the plots determines their mesoclimate, primarily in relation to minimum temperatures, causing temperature variations of up to 2.3°C. The sensitivity of the Albariño variety to mesoclimatic variability was mainly reflected in its oenological characteristics. Temperature variations favored sugar accumulation, reaching average differences of up to 10 g/L, and decreased the final malic acid content, with differences of up to 2 g/L between plots. The average total acidity of the cooler plots was slightly higher than the average of the three plots with high maximum temperatures. Differences in agronomic variables such as yield and leaf area were not related to mesoclimatic variability. Wine analysis showed no significant differences for any of the variables, except for the Total Polyphenol Index, which was 5.5 in wine from plots with high temperature ranges, while wine from plots with moderate temperatures obtained a TPI of 5.2.

Respuesta al método de pastoreo y la oferta de forraje en campo natural en el período otoño-invernal

Franco Adano Verocay — 2025-08-29

This study seeks to determine how grazing methods and forage supply, as the main modifiable variables, in addition to soil conditions, affect primary and secondary productivity and the plant composition of the vegetation cover. A 2x2 factorial design experiment was conducted on pasture 13 of the Mario A. Cassinoni Experimental Station (La - 32.387511°S and Lo -58.033235°W), evaluating two levels of supply (high and low, with combinations of 12% in autumn and 8% in winter, and 8% in autumn and 6% in winter, respectively) and two grazing methods (rotational and continuous) are being evaluated. The animals used were Holstein steers. The OF levels are adjusted monthly according to forage availability (kg DM/ha) and expected growth rate, regulating stocking rates based on monthly weighing data. The evaluation period ran from 24 April 2024 to 26 August 2024, covering the autumn and winter seasons. The aim of the study was to determine the botanical composition and primary and secondary production for the different treatments. The area was classified into three zones—Low, Medium, and Litosols—corresponding to contrasting soil types, according to cartography and visual field estimates. The variables determined were forage height (cm), forage mass present (kg DM/ha), botanical composition, and average daily gains of the animals (kg BW/a/day). For the analysis of the results, the statistical software InfoStat was used, applying multivariate descriptive techniques and analysis of variance (ANOVA), followed by Tukey's mean comparison tests with a significance level of 10%. Height was influenced by both forage supply and grazing method, with the rotational method with high supply standing out as the one that allowed for greater heights to be achieved. Likewise, a strong influence of soil conditions was observed: the highest heights were recorded in low-lying areas, while the lowest were found in lithosols. The botanical composition was mainly determined by soil conditions. An effect associated with both supply and grazing method was also observed, resulting in contrasting sets in terms of vegetation type and productivity. With regard to growth rate, effects attributable to both the area and the grazing method were evident. Low-lying areas showed a higher growth rate compared to lithosol areas, as did the rotational method compared to the continuous method. In the case of forage mass, a marked influence of the three variables (supply, method and area) was observed. Forage utilisation was determined by the method, supply and contrasting soil conditions. Animal productivity was mainly affected by forage supply. Lower losses in average daily gain were recorded under conditions of high supply, especially within the rotational system, while in the continuous method no significant differences were observed between supply levels.

Suplementación con grano de lupino (Lupinus angustifolius) en régimen de autoconsumo a terneras pastoreando raigrás

Federico Diego Bauzá Gómez — 2025-08-26

The present study was conducted during the winter season, between July 6 and September 27, at the Mario A. Cassinoni Experimental Station (E.E.M.A.C.) of the Faculty of Agronomy at the University of the Republic, located in the department of Paysandú, Uruguay. The objective of this study was to evaluate the effect of supplementation with lupin grain (Lupinus angustifolius) and the method of supply (daily or self-feeder) on intake and animal behavior in heifer calves grazing winter forages under restricted forage allowance.

Thirty-six Hereford heifers, with an initial body weight (BW) of 174 kg ± 18 kg, were blocked by BW at the beginning of the pre-experimental period (light, medium, and heavy) and randomly assigned within each block to one of three treatments: (1) ryegrass grazing without supplementation (CONTROL); (2) ryegrass grazing plus daily supplementation with broken lupin grain at a rate of 1 kg DM/100 kg BW (DS); (3) ryegrass grazing plus supplementation with broken lupin grain in self-feeders with ad libitum grain availability (AC). Each treatment consisted of three replicates, with each replicate including four heifers grazing an independent plot. The animals grazed in weekly strips with a forage allowance of 2.5% BW and were taken daily to drink water.

Supplementation improved dry matter (DM) intake regardless of the treatment, compared to the control treatment. An increase of 0.88% in DM intake (%BW) was observed in the daily supplementation treatment, surpassing the control. Moreover, this difference was even greater in the AC treatment.

The three treatments had equal conditions in terms of available forage and botanical composition (p-value > 0.05). However, significant differences were observed in the residual forage as well as in forage utilization at the end of the 7-day grazing period, the latter being greater in the control treatment. Based on these results, the effect can be classified as an addition-substitution response.

Furthermore, significant differences (p-value < 0.05) were found in the time spent grazing, with the control group spending the most time, followed by the daily supplementation treatment, and lastly, the self-feeding treatment.

Caracterización del cultivar de manzano Gvu Yvyrá respecto a sus requerimientos de frío y polinización

Diego Andrés Berriel Delbono — 2025-08-14

Apple is the main crop among temperate deciduous fruit trees, both globally and in Uruguay. Varietal replacement is one of the main challenges in fruit production. 'GVU Yvyrá' is a new national apple cultivar, resulting from a cross between 'Red Delicious' and 'Condessa'. Understanding the chilling requirements and pollinators of new apple cultivars is essential for proper site selection and management. The general objective of this study was to characterize the chilling and pollination requirements of 'GVU Yvyrá' under productive conditions in southern Uruguay. To estimate its chilling requirements, 15 shoots were collected weekly from the GVU Yvyrá, Red Delicious, and Condessa cultivars. The trial was conducted at INIA Las Brujas during the 2021–2022 season. The shoots were placed in buckets with water inside a growth chamber at 25°C and a 14-hour light photoperiod. Weekly evaluations were carried out, counting the number of sprouted buds. A cultivar was considered to have overcome dormancy when at least 50% of its buds had sprouted. Chilling accumulation was estimated using data from GRAS–INIA Las Brujas with the following models: Richardson (chill units, CU), Chilling Hours (CH ≤ 7.2°C), and the Dynamic Model (chill portions, CP). Pollination evaluation was carried out during the same productive season, in a commercial orchard of 'GVU Yvyrá' in full production (Melilla, Montevideo). The phenology of several potential pollinizers was recorded, selecting those with the most synchronized flowering for directed pollination: 'Anna', 'Dorsett Golden', 'Princesa', 'Eva', 'Condessa', 'Duquesa', and “Paco” (Malus floribunda). As results, 'GVU Yvyrá' exceeded 50% budbreak in the collection dated 08/12/2021, with an accumulation of 706.5 CU, 347 CH, and 32 CP. In this study, both 'GVU Yvyrá' and 'Condessa' showed low winter chilling requirements, with 'GVU Yvyrá' being less demanding in terms of growing degree accumulation. All evaluated pollinizers showed higher fruit set rates and seed numbers than the self-pollination controls, with the crab-type selection “Paco” and 'Eva' showing the greatest flowering synchrony with 'GVU Yvyrá'. 'Anna' had the earliest flowering, with 38% synchrony, and 'Princesa' the latest, with 65% synchrony. For proper orchard management of this cultivar, any of these four pollinizers —even in combination— can be used to achieve adequate fruit set in commercial orchards. This information should be complemented with plantings of this cultivar in non-traditional apple-growing regions with lower chill accumulation, such as northern Uruguay, where flowering synchrony with pollinizing cultivars may also vary.

Producción de HCN en sorgo y su interacción frente a estreses bióticos y abióticos

Dionisio Daniel Díaz Recalde — 2025-08-08

Sorghum (Sorghum spp.), the fifth most important cereal crop worldwide, stands out for its remarkable tolerance to water stress, making it a strategic crop in arid and semi-arid regions. In Uruguay, its increasing integration into agricultural systems has recently been threatened by the invasion of the yellow sugarcane aphid (Melanaphis sorghi), an emerging and highly damaging pest characterized by rapid parthenogenetic reproduction, wide dispersal capacity, and challenging management. Although strategies such as genetic resistance, early sowing, and seed treatments have been promoted, the defensive role of compounds like hydrogen cyanide (HCN), derived from the hydrolysis of cyanogenic glucosides, remains underexplored against piercing-sucking pests such as Melanaphis sorghi (M. sorghi), despite its proven efficacy against chewing insects like Spodoptera frugiperda. In this context, the present thesis evaluated, under controlled conditions, the interaction between water stress and the stress caused by M. sorghi in three sorghum hybrids: one with high and another with low HCN synthesis capacity (both with unknown responses to the aphid), and a third hybrid susceptible to the insect, with unknown cyanogenic capacity. Variables related to aphid population dynamics, plant physiological responses, and forage quality were analyzed. The results revealed significant differences among hybrids. The genotype with the lowest cyanogenic capacity (H3) consistently showed lower infestation, greater above-ground biomass, thicker stem, and higher SPAD index under combined stress, which contradicts the hypothesis that higher HCN production confers greater resistance. This suggests the involvement of alternative defense mechanisms, possibly environmentally induced, such as the accumulation of secondary metabolites or phloem-specific proteins. Ex situ assays showed no significant differences among hybrids, reinforcing the idea that such defenses are not structural (e.g., waxes or trichomes), but chemical and dependent on the plant's physiological state. Combined stress intensified losses in aerial biomass, chlorophyll content (SPAD), and stem thickness, particularly in the more susceptible hybrids (H1 and H2). In all cases, forage quality declined under stress conditions, reflected in increased lignin (ADL) content and reduced essential minerals, as indicated by higher NDF, ADF, and lower ash content. These findings highlight the complex, multifactorial nature of resistance to M. sorghi and emphasize the need for integrative approaches in breeding more resilient hybrids capable of withstanding increasingly frequent multiple stress scenarios.

Distribución de luz en canopias forestales en sistema silvopastoril

Juan Francisco Durán Fernandez — 2025-08-07

In silvopastoral systems (SPS), tree canopy architecture regulates the vertical distribution of radiation, affecting the productivity of the herbaceous layer, the growth of the forest component, and the microclimatic conditions in the system. This work evaluated the vertical distribution of photosynthetically active radiation (PAR) and the canopy interception efficiency of two Eucalyptus species (E. grandis and E. dunnii) under a silvopastoral system at the Bernardo Rosengurtt experimental station in Cerro Largo, Uruguay. Two types of spatial arrangements (single and triple row) and two types of genetic material (seeds and clones) were compared, evaluating light transmission using PAR measurements at different vertical strata of the canopy during the summer and winter of 2024. The results showed significant differences between species and arrangements in light interception. E. grandis presented greater volumes and heights, but a lower proportion of live canopy, which implied greater variability in transmittance. During the summer, trees grown from seed showed clear differences between species: E. dunnii had lower light extinction coefficients than E. grandis in both single and triple arrangements, indicating greater light penetration through the canopy. However, during the winter, this relationship: was partially reversed: E. dunnii showed grater attenuation in the single treatment, but less in the triple treatment. In clonal material, differences between species were minimal, and k values were practically equivalent. A seasonal effect on light attenuation was also observed, with higher extinction coefficient values in winter. These results provided insight into how canopy architecture and spatial arrangement influence light availability in silvopastoral systems, providing key information for optimizing forest and forage productivity in multiple land-use schemes. This study highlights the importance of proper species selection to optimize production in these types of systems.

Caracterización agronómica de germoplasmas de maíz de Uruguay

Esteban Miraballes Iguiní — 2025-07-22

Maize is a crop of great economic and social importance in Uruguay, used for both human and animal consumption. Therefore, studying the genetic variability present in the country is essential in order to identify varieties adapted to local conditions and possessing favorable traits in the face of adverse climatic factors, such as water deficit. In this context, the conservation of landraces becomes especially relevant, as they represent a valuable source of genetic diversity for crop improvement and sustainability.

The objective of this study was to evaluate the agronomic characteristics and yield of 15 maize varieties in Uruguay, including landraces, selection populations, and open-pollination varieties. The trial was conducted in a particularly dry year during the 2022/2023 growing season at the Experimental Station Centro Regional Sur (CRS) of the Faculty of Agronomy.

Various agronomic characteristics were evaluated, such as grain color, stem diameter, plant height, number of ears, ear height, ear height/plant height ratio, days to flowering, ear weight, and grain weight. The results showed significant differences in many of these variables, which is of great importance since genetic variability is a resource we can leverage.

The results highlight the importance of continuing to evaluate and select maize varieties that maximize their yield in adverse climatic conditions, with the conservation of criollo varieties being key as a source of genetic variability. Furthermore, it was concluded that the water deficit conditions during the experiment influenced the results obtained, underscoring the need for additional studies under different environmental conditions.

Análisis comparativo del comportamiento en pastoreo de vacas Hereford, Angus y sus cruzas durante el verano en un sistema pastoril del litoral de Uruguay

Alfonso Inzaurraga Machado — 2025-07-17

The objective of this study was to analyze the grazing behavior of Hereford, Angus, and crossbred cows during the summer in an extensive grazing system on the Uruguayan coast. The research was conducted through direct bservation over two days in January and March 2024 in the town of Young (Río Negro, Uruguay). Activities such as grazing, resting, suckling, water consumption, sun exposure, and shade use. Simultaneously, environmental data on temperature and relative humidity were collected to calculate the heat stress index (THI), used as an indicator of heat stress. Analysis of variance was applied to compare behavior between breeds and dates, as well as to evaluate the influence of the environment on the activities observed. No significant differences were found between breeds in the total time spent in shade, suggesting a homogeneous behavioral response to the environment. However, significant differences were observed between dates, associated with higher THI values in January (85.25) than in March (76.5), accompanied by longer rest times in shade. These results indicate that heat stress has a decisive influence on cattle behavior in extensive systems, beyond genetic differences between breeds. It is concluded that the design of management strategies adapted to environmental conditions—such as the provision of shade and water—is essential for animal welfare and productive resilience in the face of adverse climatic scenarios.

Componentes ecofisiológicos y numéricos del rendimiento de trigo que explican el incremento de rendimiento del período 2003-2023

Felipe Ganem Cañizas — 2025-07-09

Considering the expected increase in the global population over the coming decades, it is estimated that the demand for food will also rise in the future, with wheat being one of the primary sources of energy and protein. However, given the finite nature of resources, genetic improvement emerges as the most viable alternative to meet this growing demand.

The variability quantified in genetic progress reported by different authors introduces some uncertainty regarding how this challenge will be overcome in the future. Therefore, it is necessary to generate local information that contributes to understanding the evolution and determining factors of wheat yield.

This study aimed to analyze the evolution of yield and its main numerical and ecophysiological components, as well as to identify potential interactions and limiting factors. For this purpose, a database from the Wheat Cultivar Characterization Program at EEMAC covering the period 2003-2023 was analyzed.

The cultivars ranked in the top third of annual yield were selected and compared with two long-term reference cultivars (INIA Tijereta and INIA Churrinche) to identify the components explaining yield differences between modern and older cultivars.

The results indicate that modern cultivars exhibited a yield increase rate of 86 kg ha⁻¹ year⁻¹ (1,37% year⁻¹) (p-value: 0,0735), progressing from values close to 6000 kg ha⁻¹ to approximately 8000 kg ha⁻¹ at the end of the study period, with a yield gap of 1,700 kg ha⁻¹ between the two groups.

The numerical yield component that most significantly contributed to the yield increase was grain number (grains m⁻²), which aligns with findings from the majority of authors worldwide. In this regard, modern cultivars differed from the reference cultivars at a rate of 207 grains m⁻² year⁻¹, while grain weight (mg) remained unchanged.

Regarding ecophysiological components, an increase in biomass production was recorded, accompanied by a decline in the harvest index. Based on these results, it can be interpreted that modern cultivars exhibit lower agronomic efficiency due to an imbalance in the ratio of total biomass at harvest to grain yield.

Therefore, in the future, it will be necessary to enhance crop sink capacity, allowing better utilization of the high biomass production that is currently being underutilized.

Relaciones hídricas en dos especies de Eucalyptus en sistema silvopastoril

Santiago Barrios Miller — 2025-06-27

The forestry sector in Uruguay has shown remarkable growth, achieving an economic impact of 2.5 billion dollars in 2022, representing 4% of the national GDP. Meanwhile, livestock farming, a historical cornerstone of the country, boasts 12 million head of cattle and remains one of the primary export sectors. In this context, silvopastoral systems (SPS), which integrate forestry and livestock production, offer significant benefits such as income diversification, reduced fire risks, improved animal welfare, and a contribution to environmental sustainability. However, their adoption faces challenges related to technical management. This work aims to provide key information to foster the implementation of SPS in Uruguay. The interaction between the tree and pasture components in SPS generates complex dynamics, especially concerning competition for resources like water. Therefore, studying the water relations and stomatal conductance of Eucalyptus is essential to evaluate tree performance under different arrangements, their impact on water availability for the pasture, and ultimately, the overall sustainability and productivity of the system. The main objective was to characterize the water relations and stomatal conductance of Eucalyptus grandis and Eucalyptus dunnii in silvopastoral systems with single and triple row arrangements. To achieve this, soil water conditions, the trees' response to these conditions, and variables such as diameter at breast height (DBH) and total height were studied in contrasting seasons. The study was conducted in 2024 at the Bernardo Rosengurtt Experimental Station, located in Cerro Largo, Uruguay, on Subeutric Brunosol soils, characterized by their pastoral use. A randomized block experimental design was used, evaluating E. grandis and E. dunnii in single and triple row arrangements with 14-meter alleys. Measurements included water potential, stomatal conductance, crown characterization, DBH, and height, taken during the summer and winter seasons. The results indicated that Eucalyptus grandis showed better performance in total height and DBH, as well as a lower percentage of live crown under the triple row arrangement. On the other hand, E. dunnii, although less efficient in growth and light transmission to the soil, showed less growth in total height and DBH (Diameter at Breast Height) in single-row arrangements, possibly due to the favorable microclimatic conditions that this design offers. In terms of water relations, no significant differences were found in water potential and stomatal conductance between the different arrangements, but there were differences between species and seasons. E. grandis generally exhibited higher levels of stomatal conductance than E. dunnii, which could be attributed to species-specific characteristics. Most of the significant differences found in the study were associated with the species rather than the type of arrangement or orientation. Finally, climatic conditions, such as precipitation and water demand, significantly influenced the water potential and performance of both species. This study highlights the potential of E. grandis in silvopastoral systems and underscores the importance of proper species selection management to optimize production in these systems.

Cambios morfo-fisiológicos en Festuca arundinacea y Dactylis glomerata, creciendo bajo sotobosque

Leandro Rodríguez Fuentes — 2025-06-26

The experiment was conducted on a private property located 18.5 km from Fraile Muerto, Cerro Largo Department, Uruguay, during the spring of 2019.

The effect of trees on the physiology, morphogenesis, and structure of Dactylis glomerata and Festuca arundinacea was evaluated. Measurements were taken in single tree rows oriented north–south, with a 19 m spacing between rows, and in three perpendicular positions relative to the tree row: position I (center of the alley), position M (intermediate between tree row and center of the alley), and position Ar (near the tree row), plus an open-field control (C). The tree component consisted of 12-year-old clones of the hybrid Eucalyptus grandis × Eucalyptus camaldulensis. The experimental design was a randomized complete block design (RCBD) with split plots and three replicates within each plot. The total experimental area covered 0.3 hectares.

Regarding the morphological variables evaluated, the position relative to the trees had no effect on phyllochron, leaf appearance rate (LAR), or leaf expansion rate (LER) for either species. However, the number of live leaves per tiller (NLL) was significantly higher in position Ar compared to the control, with values of 4.61 and 3.44, respectively. A significant difference was also found between species in overall NLL, with 3.6 for Festuca arundinacea and 6.2 for Dactylis glomerata. For mean leaf length (MLL), statistically significant differences were found between shaded treatments and the control, with longer leaves observed in shaded conditions. No significant differences were found in leaf senescence rate (SR) between treatments or between treatments and the control. When comparing species, SR was 0.22 for F. arundinacea and 0.35 for D. glomerata, a statistically significant difference.

From the analysis of ETR vs. PAR response curves, no statistically significant differences were found in ETRmax, Fv/Fm, or IK between F. arundinacea and D. glomerata. However, a significant difference (p = 0.05) was found for α (slope of the rapid rise of the curve), indicating that D. glomerata has greater quantum efficiency than F. arundinacea. No statistically significant differences were found between positions in the alley.

The results of this study confirm that the presence of trees causes changes in morphology and physiology in the studied species. Quantum efficiency under trees is enhanced, as are the structural variables NLL per tiller and MLL, as a result of shading. The increase in NLL per tiller can be explained by lower senescence rates, and the increase in MLL as a shade acclimation response.

Rendimiento del doble cultivo anual trigo/soja en función de los años de agricultura continua

Natalia Foster Aranda — 2025-06-25

The anticipated increase in global food demand for the coming years must be met within current agricultural land, as the incorporation of new areas entails high environmental costs. The country's climate makes double annual cropping possible due to water availability and year-round temperature conditions. Sustainable agriculture has revived interest in crop rotation and the incorporation of pastures into the rotation. In Uruguay, deteriorating soil fertility and erosion are factors that significantly limit crop production. Tillage systems and crop rotation are management practices that can modify soil quality. The objective of this study is to evaluate the effect of soil quality as a determinant of the gap between current yield and that achievable when nutrient input is unrestricted. The experimental design involved plots divided into three randomized complete blocks. The larger plot was assigned five soil management history (HMS) treatments, while the smaller plot was assigned fertilizer management. The HMS treatments applied were LCP: conventional tillage, 50% of the time in crops, 50% of the time in pastures, with soybeans predominating in the agricultural phase; SDPsj: direct seeding, rotation with pastures and soybeans predominating; SDCsj: direct seeding, continuous cultivation and soybeans predominating; SDCsj-bch: direct seeding, continuous cultivation and high frequency of soybean-fallow; and SDCsg: direct seeding, continuous cultivation and sorghum predominating. Developing a continuous cultivation system under direct seeding and with a high frequency of first-crop soybeans in the rotation causes a deterioration in the physical properties of the soil, negatively affecting penetration resistance. It also negatively affects soil water infiltration, as does conventional tillage in rotation with pastures. Continuous cropping sequences under no-till cultivation with a predominance of sorghum maintain elevated levels of soil water infiltration. Incorporating no-till pastures into the rotation maintains higher surface COS, while conventional tillage or no-till cultivation with a predominance of early soybean in the sequence would result in lower COS levels, deteriorating soil fertility. Crop yields for wheat, soybean, and the wheat/soybean sequence were not significantly affected by any of the HMS treatments evaluated. Multivariate analysis quantified the positive impact of maintaining soil carbon and stable aggregates greater than 2 mm on wheat yield, and soil water infiltration on soybean yield. HMS, defined by no-till cultivation, would maintain better soil quality compared to conventional tillage. Treatments that incorporate pastures or grasses into the rotation show better results in maintaining soil quality.

Impacto de distintas alternativas de desecación de los cultivos de servicios en sistemas de producción bajo siembra directa

Fabricio Dutra dos Santos — 2025-06-23

Cover crops (CCs) are incorporated into agricultural systems to improve sustainability, but they require appropriate desiccation before the subsequent crop. This study evaluated two desiccation technologies (chemical and mechanical) on five species (Avena strigosa, Avena byzantina, Trifolium resupinatum, Vicia villosa, and Lupinus angustifolius) and two mixtures (Avena strigosa + Vicia villosa and Avena byzantina + Vicia villosa), comparing them to a control without cover (fallow).

The objective was to analyze the effectiveness of desiccation technologies, soil coverage, and weed control. The experiment was conducted at the Mario A. Cassinoni Experimental Station (Paysandú, Uruguay) using a split-plot design with three blocks. Variables such as green and dry soil coverage, weed density, and desiccation effectiveness were evaluated at 25, 32, and 55 days after desiccation.

Results showed that chemical desiccation was faster, while mechanical rolling achieved similar levels over time. No significant differences were found between technologies in weed density, indicating that soil coverage provided by CCs was the most influential factor in weed control.

Vicia villosa, either in monoculture or mixed with oats, was the most effective species for weed suppression, especially for resistant species like Conyza spp. In contrast, Lupinus angustifolius showed limited performance, similar to the fallow.

In conclusion, the combination of well-established CCs with mechanical desiccation is a viable strategy to reduce herbicide use and promote more sustainable systems.

Análisis de la evolución de la información generada por la ring del Plan Agropecuario en el contexto de la ganadería vacuna

Joaquín Ferreiro Fernández — 2025-06-18

The purpose of this study was to examine and describe livestock farming using the information provided by the Plan Agropecuario. To achieve this, data obtained from surveys conducted by the National Livestock Research Network were analyzed. The survey data were collected from October 2020 to early 2024. During the surveys, producers were asked various questions, which were not always the same. In this study, the questions with the highest frequency of repeated responses were selected for analysis. The methodological process was based on grouping data from surveys conducted with livestock producers across different regions of the country. Special emphasis was placed on key variables such as the amount of improved pasture area, forage production, cattle body condition, and the influence of rainfall on pasture availability. Additionally, the study explored the incidence of the screwworm (bichera) in cattle and its correlation with climatic factors. The results showed a predominance of cow-calf systems, with medium-sized farms ranging from 100 to 500 hectares. Field improvements and forage height were found to depend on the region being evaluated and the climatic conditions of the period. The screwworm was more affected by temperature than by other variables and was present throughout the country, with higher incidence in the north. The body condition of breeding cows was generally stable but was primarily affected by forage shortages.

Sustitución parcial de maíz por arroz con cáscara (GACC) en raciones de engorde de vacunos

Francisco Paravis Bonomi — 2025-06-16

The present study aimed to evaluate the effect of partially replacing corn grain with paddy rice grain (PRRG) in steer fattening rations containing 20% bale, as well as the effect of PRRG processing (cracked vs. ground) and moisture content (dry vs. wet) on animal intake, digestion, and performance. Traditionally, corn grain is the main ingredient in intensive fattening diets due to its high energy value and digestibility. PRRG was proposed as a potentially viable alternative, especially in the face of adverse market conditions or unfavorable weather conditions for the rice industry. The study was conducted at the Intensive Meat Production Unit (UPIC) of the Mario A. Cassinoni Experimental Station (EEMAC) in the city of Paysandú, Uruguay, under open-air confinement conditions. Forty-eight Hereford steers were randomly assigned in a block design to one of four experimental diets, which differed in grain type (corn or SGA), degree of SGA processing (cracked vs. ground), and SGA moisture level (dry vs. wet), offered ad libitum for 77 days. The animals were slaughtered on a fixed date at the Casa Blanca Slaughterhouse in the department of Paysandú. The results showed that the inclusion of ground GAS as a substitute for ground corn did not affect dry matter intake (P = 0.7051), but reduced dry matter digestibility (P = 0.0001) and consequently the daily intake of digestible dry matter (P = 0.0001). The inclusion of GAS is proposed as an alternative to partially replace corn in feedlot fattening diets for steers, opening a new opportunity to integrate rice production with livestock.

Turismo rural y desarrollo comunitario

Lucía Cordero González — 2025-06-10

This final degree project analyzes the formation and development process of the Rural Tourism Group La Cooperaria, an initiative led by women in the Colonia Instrucciones del Año XIII, located in Cololó, Soriano, Uruguay. The group emerged with the goal of generating income and promoting the economic autonomy of its members through community-based rural tourism, in a context where employment opportunities for women are limited and rural labor is heavily masculinized.

The general objective of this work is to understand the functioning of the Rural Tourism Group La Cooperaria (G.T.R.L.C.) in order to contribute guidelines for the development of an economic autonomy project managed by a group of women in the Colonia Instrucciones del Año XIII.

To achieve this, a qualitative research approach was used, based on the systematization of the group process, the analysis of internal dynamics, and the identification of opportunities for strengthening the initiative. Key aspects reviewed include internal organization, inter-cooperation with other local groups, the relationship with the Cooperative Unit No. 1, and the sustainability of the tourism project.

The findings show that, while rural tourism has proven to be a viable alternative for employment generation and for valuing women's work, the group faces challenges in terms of internal functioning and the consolidation of its tourism services. The importance of organizational strengthening strategies and training is emphasized, along with the need for greater institutional recognition and support from public policies that promote community-based rural tourism with a gender perspective.

Based on these findings, the project proposes a series of action guidelines aimed at improving the group’s functioning, strengthening its community integration, and ensuring its long-term sustainability. The experience of the Rural Tourism Group La Cooperaria stands as a relevant case within rural cooperativism in Uruguay and as a reference for other rural tourism initiatives led by women in the region.

Productividad de festuca bajo manejos de intensidad y frecuencia contrastantes

Gastón Camacho Sauco — 2025-05-30

This final degree dissertation examines the impact of different defoliation intensity and frequency managements on the productivity of Festuca arundinacea var. Estanzuela Tacuabé, a perennial grass essential for pasture-based systems in Uruguay. The objectives included quantifying dry matter production, botanical composition, and the effects on pasture structure during the second year of establishment. The study, conducted at the Dr. Mario A. Cassinoni Experimental Station, tested two grazing frequencies (2 and 4 leaves) and two defoliation intensities (30% and 70%) in a randomized complete block design. Results indicated that high frequency (2 leaves) combined with moderate intensity (30%) optimized growth rates in winter, while higher intensity (70%) favored regrowth under spring’s water stress conditions. Contrasting management strategies significantly affected fescue persistence and pasture composition. This research highlights the importance of tailoring management practices to seasonal conditions to maximize productivity without compromising system sustainability. These findings provide valuable insights for improving the efficiency and sustainability of pasture-based livestock systems in Uruguay.

Estudio de la calidad de carne producida por novillos de la raza Wagyu alimentados con subproductos de alto contenido lipídico

Inés María Algorta Lomiento — 2025-05-30

Despite the differentiated value of its beef that positions Uruguay as a competitive country, the pursuit of excellence in meat quality continues. The objective of this study was to evaluate whether the addition of high-lipid-content product during the finishing phase of Wagyu steers could improve meat quality in terms of organoleptic characteristics such as tenderness, juiciness, flavor, and overall liking. The study involved 16 animals fed diets with and without a lipid addition supplementation, divided into two treatments: ‘Wagyu with added lipids', ‘Wagyu without added lipid’, and , and a third treatment used as a breed effect control, called 'Non-Wagyu'. The method used to evaluate the meat was a Sensory Evaluation Panel conducted at “UTEC” in Paysandú, where 52 participants rated each of the variables on a 1 to 9 hedonic scale for all three treatments. An analysis of variance was then performed using the GLIMMIX procedure of the SAS software. The results indicated significant effects among all treatments and did not align with the initial expectations, as the highest scores for all evaluated characteristics were obtained by the ‘Wagyu without lipid addition’ treatment, followed by ‘Wagyu with lipid addition’, and finally the ‘Non-Wagyu’. Based on these results, it is concluded that the addition of lipids did not improve the evaluated organoleptic characteristics; however, the Wagyu breed continues to show superiority over the 'Non-Wagyu' breed. Nevertheless, laboratory analysis of the meat and an economic cost assessment should be carried out to contribute to the study.

Caracterización anatómica y peso específico de la madera de las dos especies leñosas nativas más frecuentes en el área protegida “Esteros y Blanqueales del Río Uruguay” Neltuma nigra (Griseb.) C.E. Hughes & G.P. Lewis, comb. nov. y Schinus longifolia (Lindl.) Speg.

Carlos Maximiliano Chabert Erausquin — 2025-05-29

Introduction: This study examined the quantitative and qualitative anatomical characteristics of the wood in two native species, Neltuma nigra (Algarrobo) and Schinus longifolia (Molle). The research had place in the conservation area "Esteros y Blanqueales del río Uruguay" at the Mafalda establishment of United Paper Mills – UPM – Forestal Oriental, in Quebracho, Paysandú, Uruguay.

Methodology: Dendrometric measurements were recorded from individuals present in selected plots within the conservation area. Cores were extracted using a Pressler borer and processed in the laboratory according to Wheeler et al. (1989). Vessel diameter and length, fiber length and width, vessels per mm², dimensions and frequency of parenchymatic rays were measured. Crystals and fiber-tracheids were also identified, and the basic apparent specific gravity was calculated using Archimedes’ principle. For S. longifolia, as it was the first recorded study, the data were compared with those of other species of the genus Schinus, showing similarities with S. molle: vessels of 232.0 µm in height, 34.6 µm in width, 162.7 vessels/mm² and average density of 0.82. Rays measured 262.9 µm in length and 26.2 µm in width; fibers, 683.5 µm in length by 17.0 µm in width. N. nigra presented vessels of 149.8 µm in length and 117.0 µm in diameter, with 15 vessels/mm²; fibers of 911.2 µm in length by 14.4 µm in width. Rays measured 370.1 µm in length and 67.5 µm in width, with a frequency of 5.3 rays/mm. Rhombohedral crystals were observed in parenchymatic cells and an average basic density of 0.83 g/cm³ was obtained, classified as heavy wood.Final del formulario

Results: The study reveals that both species have high density, suggesting their potential as high-quality structural wood. Further research will generate a better understanding of their properties and applications. Additionally, density analysis is crucial for making more accurate biomass estimates, which could have significant implications for ecological studies and forest management. The comparison of anatomical characteristics between species from different regions of South America, in the case of N. nigra, allowed for a deeper understanding of the relationship between these properties and geographic locations, enriching knowledge about biodiversity and species adaptation within the same habitat. This study represents the first anatomical characterization of S. longifolia, while findings regarding N. nigra indicate that its properties are comparable to those of other populations in the Argentine Chaco. Together, these results contribute to the understanding of anatomical variability within the regional ecological context and open new avenues for future research.

Respuesta vegetativa y productiva de Vitis vinifera L. cv Tannat A la práctica de deshojado en diferentes momentos fenológicos del ciclo

Vicente Curbelo Rial — 2025-05-29

During the 2018-2019 harvest, an experiment was carried out with the aim of evaluating the aim of evaulating the effect of leaf removal by the effect of defoliation by manual defoliation at different phenological moments of the grapevine cycle. To evaluate its influence on the microclimate of the cluster, the vegetative expression of the plants, the yield components and the chemical composition of the grapes at harvest were analysed. The experiment was carried out in a vineyard of the cv.Tannat/SO4 (clone 398), with SO4 rootstock, trained on a VSP system (Vertical Shoot Positioned) with bilateral Guyot pruning, located in a commercial vineyard in the town of Juanico, department of Canelones. The defoliation treatments were carried out at pre-flowering (DPF), at fruit set (DC) and at veraison (DE) and were compared with a control without defoliation (TC). The statistical design was a randomised complete block with three replicates and the experimental unit was seven plants. Defoliation was performed manually at the cluster level with an intensity of 70% for DPF and 20% for DC and DE. Defoliation changed the composition of the canopy and thus the microclimate where the bunches were exposed. Defoliation resulted in a 20% reduction in yield compared to the control. In terms of bunch compactness, DPF resulted in fewer berries per bunch, resulting in less compact bunches. The defoliation practice improved the vegetative-productive balance of the plants, which showed a shift towards the vegetative component. With regard to the grape polyphenolic evaluated at harvest, defoliation at fruit set (CD) favoured the concentration and accumulation of potential and extractable anthocyanins compared to the control.

Efecto del manejo del pastoreo en la recría de borregas en campo natural

Fernanda Bentancur Coppetti — 2025-05-23

This study was conducted at the Palo a Pique Experimental Unit of INIA Treinta y Tres, Uruguay (33°15'10''S, 54°30'15''W, at 45 m above sea level), located in the Sierras and Lomadas del Este region, within a 30-year long-term experiment (LTE). This Final Degree Project was developed using data from the first three years of the experiment (2021–2022, 2022–2023, and 2023–2024). The central issue addressed is how grazing management, through different grazing intensities based on sward height, affects forage structure and animal production. In this context, the objective is to identify the optimal sward structure(s) for proper management, aiming to achieve higher animal productivity. This would allow for increased production and reduced risk under adverse conditions (e.g., drought).The experimental design was a randomized complete block design with four different forage structures based on pasture height (T4 = 4 cm, T8 = 8 cm, T12 = 12 cm, and T16 = 16 cm). Key variables such as sward height, forage mass, stocking rate, individual live weight gain, and productivity per unit area were estimated. Climatic monitoring was carried out using records from the on-site weather station. For data analysis, mixed linear models were applied using R software. For forage-related variables (height and biomass), treatment was considered a fixed effect, while block, measurement, and year were treated as random effects. For animal production variables (individual and per-hectare gains), treatment was also considered a fixed effect, and block and year as random effects. Pairwise comparisons between treatments were performed using Tukey’s test, with a significance level of 5%. The average pasture heights for each treatment were 3.8 cm for T4, 7.9 cm for T8, 10.1 cm for T12, and 12.3 cm for T16, with the latter two not reaching the target heights. Regarding forage mass, significant differences were observed among treatments (T4 = 508 kg DM/ha; T8 = 1,731 kg DM/ha; T12 = 2,313 kg DM/ha; T16 = 2,682 kg DM/ha). Results indicated that the higher height treatments (T12 and T16) promoted greater individual weight gain (0.048 and 0.051 kg/animal/day, respectively), while the lower height treatments (T4 and T8) optimized productivity per hectare, albeit with lower individual performance (0.035 and 0.041 kg/animal/day, respectively). In conclusion, treatments T8 and T12 promoted the best functional balance between pasture structure, individual gain, and productivity per hectare of the ewe lambs. This intermediate height range (8–12 cm) allowed for adequate sward recovery, favoring canopy structure. These findings contribute to the development of grazing management strategies that balance animal productivity with the conservation of the forage resource.

Sustitución parcial del grano de maíz por grano de arroz con cáscara en raciones de engorde de vacunos

Mariana Bassagaistéguy Dupetit — 2025-05-21

The experiment was conducted at the Intensive Meat Production Unit (UPIC) of the “Dr. Mario A. Cassinoni” Experimental Station (EEMAC) in Paysandú, Uruguay, from June 24 to October 2. The objective was to evaluate the effect of partially replacing ground corn grain in the diet with rice grain with hulls (GACC) of different processing levels and moisture content on the performance of feedlot-finished steers. Growth curves were described, and live weight gain and feed conversion efficiency were quantified for each treatment. The study involved 48 Hereford steers from the EEMAC experimental herd, born in spring 2022, with an initial average weight of 363.7 ± 17.8 kg. The animals were assigned to four blocks according to live weight and then randomly allocated to four treatments. Each treatment consisted of a total mixed ration (TMR), resulting in 16 groups of three animals each. Each group was housed in a separate pen, and each treatment was made up of four pens, each considered an experimental unit. All four TMRs had a forage-to-concentrate ratio of 20/80, differing in the type of grain (45% ground corn at 14% moisture or 45% ground GACC at 14% moisture), processing level (45% cracked GACC at 14% moisture), and moisture content (45% cracked GACC with 77% dry matter). The replacement of corn grain with rice grain with hulls in the steers' diet affected feed conversion efficiency when comparing processing level and moisture content. The feed conversion efficiency (FCE) for the TMR with ground GACC was 6.48 kg DM/kg BW, and for cracked GACC it was 6.94 kg DM/kg BW—representing a 7% improvement with smaller particle size. For the TMR with wet cracked GACC, the result was 6.36 kg DM/kg BW, showing an 8% improvement in feed conversion efficiency with higher grain moisture content. There were no significant changes in average daily gain (ADG) or dry matter intake (DMI), with averages recorded at 1.98 ± 0.09 kg/day for ADG and 3.14 ± 0.07 %BW for DMI. This indicates that, in feedlot diets, GACC could have potential as an energy source.

El destete racional como estrategia para promover el bienestar animal y las ganancias de peso vivo, minimizando pérdidas en condición corporal en raza Braford

Guillermina Dutra Ospitaleche — 2025-05-15

The aim of this study was to evaluate the effect of two weaning methods, traditional (TW) and rational (RW), on the behaviour, body condition (BC), live weight (LW), and metabolism of multiparous Braford cows. The study was conducted at a cattle farm in Artigas, Uruguay, from late March to May 2024, under uniform conditions for all animals.

A total of 109 cows, pregnant in the first third of gestation, were randomly assigned to two groups: 54 to RW and 55 to TW. In TW, cows and their calves were moved to pens where they were separated, after which the cows returned to their paddock. In RW, the separation occurred within the paddock using a corner enclosure.

Behaviour (walking, standing, and feeding) was recorded for 7 days post-weaning. LW, BC, and levels of glucose and total protein were measured before and after weaning using blood samples collected by coccygeal venepuncture.

The results showed that RW cows spent more time feeding, walked less, and spent less time standing compared to TW cows (P < 0.0001). Although there were no significant differences in metabolic responses between methods, a significant variation was observed in sampling dates within each group. RW positively influenced cow behaviour and was associated with a significant increase in glucose levels over time, suggesting a lower stress response and better adaptation to the process compared to TW. These results were reflected in the BC, which was significantly higher (P < 0.05) in the RW cows, with a 5.5% increase compared to those in the TW group. Regarding live weight, no significant differences were detected between treatments, although the RW cows were, on average, 2% heavier than those in the TW group.

Estudio de la resiliencia productiva del campo natural bajo intervenciones de largo plazo post estrés hídrico estival

Victoria Nazarena Franchi De Gregorio — 2025-05-15

The experiment was conducted at the Mario A. Cassinoni Experimental Station (Faculty of Agronomy, Udelar) in Paysandú, Uruguay. The resilience of natural grassland after experiencing summer water stress and its productive response to nitrogen fertilization and the introduction of legumes were evaluated. The study covered two subperiods: autumn–winter (May 10, 2023 – July 18, 2023) and winter–spring (July 19, 2023 – September 25, 2023), under a rotational grazing system (15 days of grazing and 45 days of rest). The experimental design was a Randomized Complete Block Design (RCBD), divided into four blocks, each containing four plots. Four treatments were evaluated: an untreated control (CN), improved natural grassland with legumes (CNM), and nitrogen fertilization at 60 kg N/ha/year (N 60) and 120 kg N/ha/year (N 120), applied in the autumn–winter period. All treated plots received 40 kg/ha/year of P₂O₅ in autumn. Variables directly measured included pre-grazing and post-grazing dry matter, as well as the height of pre-grazing and post-grazing dry matter. Based on these data, additional variables were calculated: available, disappeared, and produced dry matter, daily growth rate, botanical composition (including fourteen plant groups), total stocking rate, average daily gain, meat production per hectare, and forage supply. Mean comparisons were carried out using Tukey's test and orthogonal contrasts. According to Tukey’s test, considering the entire study period, total dry matter production was significantly higher in the treatment with 60 kg N/ha (N 60) compared to the other treatments. Regarding the daily growth rate, no significant differences were observed among treatments. Biomass production was significantly higher in the winter–spring subperiod compared to autumn–winter. Average daily gain did not differ significantly between treatments. Total meat production was higher in the nitrogen treatments and in CNM, with the nitrogen treatments showing the highest absolute values; however, no statistical analysis was performed for this variable due to lack of replication. CNM appears to be a viable alternative to improve the productivity of natural grasslands.

Cambios en las variables estructurales por efecto de la intensidad y frecuencia del pastoreo y la incidencia en la productividad en festuca

Juan Manuel Ordoñez May — 2025-05-09

This thesis addresses the impact of different defoliation management strategies, varying in intensity and contrasting frequencies, on the productivity of Festuca arundinacea var. Estanzuela Tacuabé, a key perennial grass in pastoral systems in Uruguay. The objectives included quantifying changes in the vegetative structure of tall fescue under contrasting grazing intensities and frequencies, as well as assessing the impact on flowering management. This study was conducted at the Dr. Mario A. Cassinoni Experimental Station, where two grazing frequencies (2 and 4 leaves) and two defoliation intensities (30% and 70%) were combined in a randomized complete block design. The results showed that lower grazing intensity (30%) had a positive effect on leaf and tiller weight compared to higher intensities (70%). Similarly, lower grazing frequencies (4 leaves) resulted in greater weight compared to higher frequencies (2 leaves). Overall, a less intensive grazing management approach favored foliar recovery and growth. However, higher grazing intensities and frequencies (2H 70) led to a higher total number of tillers. Additionally, lower grazing frequencies increased available LAI and intercepted %PAR, while higher grazing frequencies and intensities reduced these values. This study highlights the effect of management practices and the importance of adjusting grazing strategies to seasonal conditions to maximize system productivity and efficiency.

Sandía

Mónica Kaetsu Torii — 2025-05-06

Watermelon [Citrullus lanatus (Thunb.) Matsum. et Nakai] is one of the most commercially traded and demanded fruits during the summer. In 2023, 7,493 tons of watermelon were delivered to the main wholesale market in Montevideo, the Unidad Agroalimentaria Metropolitana (UAM), 6,443 tons of which originated from the department of Rivera, Uruguay's principal production region. This study aimed to evaluate the postharvest quality of watermelon fruits marketed at the UAM under refrigerated conditions (11°C and 98% relative humidity) at the beginning (0 days) and after 7, 14, 21, and 28 days of storage. At each sampling point, the effects of refrigerated storage time on weight loss, external appearance, specific weight, rind and pulp color, pulp appearance, firmness, juiciness, total soluble solids (TSS), juice content, pH, titratable acidity (TA), total carotenoids and lycopene content, total polyphenols (TP), and total antioxidant capacity (TAC) were assessed. The experimental design was completely randomized (CRD) with five treatments (0, 7, 14, 21, and 28 days). Watermelons were randomly stored in a refrigerated chamber (41 fruits), and at each sampling point, 8 randomly selected fruits (replicates) were analyzed, with time (days) as the factor. The results showed that certain physical and chemical attributes, such as dimensions, specific weight, rind color, firmness, TSS, pH, TA, and pulp juice percentage, remained unchanged during the 28-day storage period. However, other attributes, including weight loss and the overall external and pulp appearance, were affected. The pulp color changed from a dark red hue up to 7 days to a lighter, less red tone, indicating overripeness and/or quality deterioration, along with a decrease in total carotenoid and lycopene content. TP content increased by 36% during the last week of storage, while TAC, measured using the DPPH method, decreased by 57%. In contrast, minor changes were observed using the ABTS and FRAP methods. The content of nutritionally significant and bioactive compounds contributing to pulp color and antioxidant capacity maintained pulp quality at acceptable levels up to 14 days. This study characterized, for the first time, the refrigerated storage of watermelons marketed at the UAM, quantifying and evaluating the preservation of physical attributes, nutritional and bioactive compounds, and antioxidant capacity in the fruit pulp.

Dinámica del nitrógeno en maíz posterior a cultivos de servicio invernales

María Ángela Cerrutti Rodríguez — 2025-05-06

In recent decades, agricultural intensification in Uruguay has generated negative effects on the soil and environment, such as erosion, loss of biodiversity, and contamination from agrochemicals. In this context, cover crops (CC) have emerged as a key tool for more sustainable agriculture, thanks to their ability to improve soil health and provide ecosystem services. The hypotheses of this thesis were: (1) that CCs consisting of grass-legume mixtures maintain high productivity and good residue quality in different environments; and (2) that CCs including legumes improve nitrogen (N) dynamics in the soil compared to long fallows or CCs without legumes, which can be measured through variations in soil nitrate (N-NO₃⁻) levels. The general objective was to study the effect of different winter CCs on N dynamics. The specific objectives were: (1) to evaluate biomass production, N contribution, and the C/N ratio of different CCs; and (2) to quantify N-NO₃⁻ availability according to the winter predecessor at different stages of the maize crop cycle. Over two years, a network of four experiments was established in two locations, each with a randomized complete block design with nesting. Each experiment included five treatments: Avena byzantina (pure grass), chemical fallow (control), Vicia villosa (pure legume), Avena strigosa + Vicia villosa (mixture), and Avena byzantina + Vicia villosa (mixture). Biomass production, N content, and N-NO₃⁻ release were evaluated. The results indicate that CCs incorporating Vicia villosa captured more N and had a lower C/N ratio, promoting a faster and more sustained release of N into the soil. Compared to pure Vicia villosa CCs, mixtures produced more biomass but with a higher C/N ratio. The percentage of Vicia villosa in the biomass of the mixture was a determining factor in soil N-NO₃^- levels throughout the maize cycle. Grasses generated more biomass but had a higher C/N ratio, leading to N immobilization in the soil and lower soil N-NO₃^-levels. It is important to highlight that considering agroclimatic variability and field history, along with proper CC management, is crucial for optimizing N use efficiency and contributing to the sustainability of the agricultural system.

Evaluación del comportamiento de la variedad Tannat frente a diferentes coberturas vegetales en la fila como alternativa al uso de herbicidas

Gisella Beatriz Hernández Frías — 2025-04-25

Given the effects of climate change on vitiviniculture, it is prudent to seek alternatives to current vineyard management to achieve sustainable production over time that allows producers to meet their production objectives.

In the present work, the use of pastures under the row accompanied by irrigation is proposed as an alternative to traditional vineyard management. Using, in turn, different sources and forms of nitrogen application. Looking to measure the effect of these on the Tannat variety, through the study of yield, physiological balance of the plant and the final composition of the berries.

The practices were carried out in the 2022 - 2023 harvest, in a vineyard located in the department of Canelones. The vineyard under study was trained on a vertical shoot positioning system, with unilateral guyot pruning. The planting density is 4000 plants per hectare and rows oriented north-south.

The inter-rows were kept with grass cover as usual, while in the rows different treatments were tested, which were white clover (Trifolium repens), one and two years old fescue (Festuca arundinacea) and herbicide.

Three fertilization methods were used, consisting of urea applied to the soil, foliar urea and coron (foliar nitrogen fertilizer), in addition to a control without fertilization. Irrigation was also used in order to maintain control of water stress that could be caused by competition with pastures.

In the results obtained, it should be noted that the data are influenced by an important year effect, since it was an atypical year in terms of rainfall and temperatures. This is reflected in the water potential which, in turn, had a significant influence on several parameters such as vegetative growth and reproductive development, masking the possible differences between herbicide and cover crop treatments.

According to the different pastures used, in the clover treatment, promising results were obtained with respect to the levels of foliar nitrogen and yeast assimilable nitrogen. Values significantly higher than the rest of the treatments were achieved in both parameters, although they were not reflected in other parameters, such as the potential exposed leaf area or yield.

The different fertilization methods did not provide clear data. But, in general, better results were observed in the treatments with foliar fertilizers. Considering that, in these methods, less nitrogen units were applied, this would indicate a higher efficiency of use by the vine plants.

Evolución de la composición y síntesis de compuestos fenólicos de plantas de Marselan sometidas a regulación fuente/fosa en dos terroir vitícolas del sur de Uruguay

María Fernanda Lauz Fernández — 2025-04-11

Viticulture in Uruguay has undergone constant evolution, driven by the pursuit of higher quality and its integration into the international market. In this context, the Marselan variety, a cross between Grenache Noir and Cabernet Sauvignon, has demonstrated high oenological potential. However, scientific information regarding its behavior under different terroirs and agronomic management practices remains scarce. This study aims to analyze the impact of source-sink regulation on berry ripening and the synthesis of secondary metabolites in two viticultural regions in southern Uruguay.

The study was conducted during the 2020-2021 season in commercial vineyards located in Los Cerrillos and Garzón, two regions with marked differences in soil and climate. A randomized complete block experimental design was used, with three treatments: (1) control treatment (TC) with no intervention, (2) pre-flowering leaf removal (DPF) performed at Eichhorn and Lorenz phenological stage 17, and (3) fruit set leaf removal with crop thinning (DC+R) performed at stage 27, followed by cluster thinning between stages 33 and 35 of the same scale. Berry samples were collected at three time points before harvest, analyzing soluble solids, acidity, pH, total polyphenols, anthocyanins, and tannins. Total polyphenols were analyzed using the Folin-Ciocalteu method, measuring absorbance at 765 nm. Total anthocyanins were quantified using the Riberéau-Gayon and Stonestreet (1965) method, measuring absorbance at 520 nm. Tannins were determined through the methylcellulose precipitation method according to Sarneckis et al. (2006), with readings taken at 280 nm using a spectrophotometer. These methods allowed for the evaluation of the concentration and evolution of different phenolic compounds at three key moments during berry ripening.

The results showed that the DC+R treatment increased the accumulation of soluble solids, total polyphenols, and anthocyanins in both locations, with a more pronounced effect in Los Cerrillos, where it accelerated berry ripening and enhanced the synthesis of secondary metabolites. The DPF treatment exhibited terroir-dependent behavior: in Los Cerrillos, it had no significant impact on phenolic compound accumulation or berry ripening, whereas in Garzón, it reduced yield and promoted the synthesis of total polyphenols and anthocyanins in the berries.

The findings of this study highlight the importance of managing the source-sink relationship through leaf removal and crop load adjustment techniques tailored to specific terroir conditions. These strategies optimize ripening and improve the oenological quality of Marselan grapes, contributing to the production of high-end wines and the development of the Uruguayan wine industry.

Susceptibilidad de Rachiplusia nu (Lepidóptera: Noctuidae) a la proteína Cry1A(c) expresada en soja Bt Y a insecticidas

Agustina Rodríguez Cerrudo — 2025-04-10

Rachiplusia nu is one of the main soybean pests in Uruguay. Its control relies on the application of insecticides and the use of Bt soybean expressing the Cry1A(c) protein. Currently, Bt soybean accounts for approximately 20% of the cultivated area; however, resistance detected in R. nu populations in neighboring countries raises concerns about its effectiveness in Uruguay. Furthermore, failures in chemical control observed in different regions suggest variations in insecticide susceptibility. This study had two objectives: (1) to compare survival, foliar consumption, and feeding indices of R. nu larvae fed on Bt and non-Bt soybean, and (2) to assess larval mortality after exposure to leaves treated with chlorantraniliprole, triflumuron, or emamectin benzoate. The study was conducted at INIA La Estanzuela (Colonia) using larvae obtained from adults collected at the Dr. Mario A. Cassinoni Experimental Station (Paysandú). To evaluate feeding performance, third-instar larvae were individually placed in cages containing a leaflet from either Bt soybean (DM 5958 RSF IPRO) or non-Bt soybean (Génesis 5501). Insecticide susceptibility was assessed by immersing non-Bt soybean leaves in solutions containing water or insecticides at three concentrations (recommended dose, half dose, and double dose), following validated protocols (Insecticide Resistance Action Committee, IRAC). These leaves were then offered to second- and third-instar larvae, and mortality was recorded. Results from the Bt soybean assay showed that after four days of feeding, larval survival was 100% in both soybean types. Defoliation was lower in Bt soybean (9.91%) compared to non-Bt (17.4%); however, total foliar area consumed was similar in both treatments. No differences were observed in the growth rate, although larvae feeding on Bt soybean exhibited greater efficiency in food conversion. Relative consumption was higher in non-Bt soybean, while leaf digestibility did not differ between treatments. Since the soybean varieties used were not isogenic, these results may reflect confounding effects unrelated to the transgenic event. Regarding insecticide susceptibility, emamectin benzoate caused 100% mortality within 48 hours, while chlorantraniliprole reached this level by 94 hours. Triflumuron showed 70% efficacy at 48 hours and 90% at 96 hours. The findings suggest a loss of susceptibility of R. nu to Bt soybean and demonstrate effective control with the evaluated insecticides when applied at recommended doses. These results underscore the importance of monitoring both Bt and non-Bt crops and highlight the need to optimize insecticide application quality to ensure adequate pest exposure to the active ingredient.

Producción de biomasa aérea, radicular y aportes de nitrógeno de distintos cultivos de servicio invernales

Bruno Sebastián Pistón Aguilar — 2025-04-10

Uruguay has maintained, over the years, a continuous agricultural system that has contributed to the degradation of its soils, resulting in a progressive decrease in productivity, low nitrogen input by crops, decrease in biodiversity, increased use of herbicides, and erosion caused by periods of bare soil. In response to these challenges, cover crops have emerged as a partial solution to mitigate these issues, improving soil fertility, controlling erosion, and increasing biodiversity. The main objectives of this study are to evaluate the production of aerial and root biomass in cover crops in the top 20 cm of soil. Additionally, to estimate the nitrogen contribution of different winter cover crops. The following varieties were used for this purpose: Avena strigosa, Avena byzantina, Vicia villosa, Lupinus angustifolius, Trifolium resupinatum. Furthermore, mixtures formed as follows were used: Avena byzantina + Vicia villosa, Avena strigosa + Vicia villosa, arranged in a randomized complete block design with three replications. The results showed significant differences (p≤0.05) in aerial biomass production. Avena strigosa achieved the highest average production, with 10,398 kg DM ha-1. In the analysis of functional groups, grasses reached an average aerial biomass production of 9,126 kg DM ha-1. For root biomass, Avena strigosa also led with 1,921 kg DM ha-1, and the group of grasses had the highest average root biomass production, recording 1,705 kg DM ha-1. Furthermore, a direct and positive relationship between aerial and root biomass production was evidenced. The analysis of nitrogen contribution and the C/N ratio showed significant differences (p≤0.05) between functional groups. The mixture of Avena byzantina (high density) with Vicia villosa presented the highest nitrogen contribution, with 151 kg/ha and a C/N ratio of 25/1, indicating good efficiency in nitrogen fixation. Overall, the mixtures had the highest nitrogen contribution (139 kg/ha), similar to that of legumes (119 kg/ha), but significantly higher than that of grasses. Regarding the C/N ratio, legumes showed the lowest value (13/1), in contrast to grasses (40/1).

Efecto de la profundidad y la capacidad de almacenaje de agua del suelo en el rendimiento de soja

Franky Yoher Benítez Giordano — 2025-04-08

In our country, most of the agricultural area is rainfed. Given the significant interannual variability in precipitation, it is crucial to understand how different environmental conditions influence yield generation. This knowledge helps identify ways to mitigate the risks associated with a potential water deficit, particularly in summer crops, when evapotranspiration is higher and the risk of drought is greater.

This study presents the following hypotheses: i) The soil’s available water storage capacity (CAAD) is relevant for mitigating the effects of precipitation deficits, especially during the critical period when the most important numerical component of yield is defined.
ii) The possibility of mitigating this effect depends on soil depth.

Data collection was carried out on agricultural fields located in the country's most important agricultural basin. The potential yield achieved—without the influence of diseases or pests—was measured, along with environmental water supply, radiation, and temperature throughout the crop cycle and at different growth stages. Additionally, soil depth was measured, and different horizons were characterized and analyzed to estimate the available water storage capacity at each site.

A quantitative analysis of the data was performed using the statistical software Infostat/E, applying multiple linear regressions to quantify the effects of CAAD and soil depth on soybean (Glycine max) yield.

The data were analyzed comprehensively and also segmented based on different water supply conditions during the critical yield-defining period (R4-R6) and throughout the crop cycle. An analysis was also conducted on fields with supplemental irrigation and under rainfed conditions.

The results showed a yield response to CAAD of 21 kg per mm. A response to soil depth was also observed, with a greater effect under rainfed conditions, where the increase was 10 kg per cm of additional soil depth.

When the dataset was segmented based on total water supply during the crop cycle, a yield response was found under medium water availability conditions (421–450 mm), with an effect of 10 kg per cm of increased soil depth.

During the critical period, a response was observed only when water supply was ≤ 90 mm, with an effect of 8 kg per cm of increased soil depth.

It was demonstrated that soil depth influences yield, with variations depending on environmental water availability. However, under unfavorable—though not extreme—conditions, soil depth provides an additional level of security for decision-making, serving as a way to mitigate the risks associated with water availability.

Efecto residual de la cobertura invernal sobre el suministro de nitrógeno y el rendimiento de cebada sembrada después de maíz y soja

Joaquina López Selios — 2025-04-08

This study addresses the impact of winter cover crops (CCs) on nitrogen (N) supply and the yield of barley sown after corn and soybeans. Recognizing the issues of soil degradation caused by production systems characterized by limited crop diversity and long fallow periods, the study proposes alternative CCs: grasses, legumes, and their mixtures, to protect the soil during winter fallows. These CCs aim not only to prevent erosion but also to improve agricultural sustainability by fixing or recycling nutrients. The main objectives of this study are: quantify the residual effect of annual crops sown to cover the soil during winter on the "nutrient supply" service and the barley yield sown after two summer crops predecessors and to determine if there is a possible interaction with nitrogen fertilization when the summer crop predecessor is corn. Different CC varieties and mixtures were used: Avena byzantina, Vicia villosa, and their mixture (Avena byzantina + Vicia villosa). The experiment was conducted at the Mario A. Cassinoni Experimental Station (Paysandú), using a randomized complete block design for soybean and a split-plot randomized complete block design for corn. Parameters evaluated included soil nitrate concentration, biomass production, and nitrogen uptake. Results indicate that legume CCs, such as vetch, excel in nitrogen fixation and availability in the soil, while grass CCs, such as oat, are more effective at providing soil cover. The mixture of both types combined these benefits, maximizing biomass production and improving N use efficiency. Regarding subsequent crops, barley showed better yields following legume CCs or mixtures, especially after corn as the previous crop. However, these differences were not always statistically significant. Climatic conditions, such as drought, affected nutrient dynamics and yields. The thesis concludes that the inclusion of winter cover crops generates a residual effect on nitrogen supply, which extends at least to the second crop in the sequence. The implementation of legumes and mixtures is essential for agricultural sustainability, as it reduces dependence on fertilizers and improves soil conservation. Although they involve initial costs, their implementation provides long-term benefits for the productivity and health of the agricultural ecosystem. While they involve initial costs, their implementation provides long-term benefits for productivity and agricultural ecosystem health.

Caracterización de clones de Eucalyptus grandis e híbridos interespecíficos con antecedentes de estrés hídrico a través de parámetros fotosintéticos y morfológicos

Andrea Larrosa Cassina — 2025-04-02

Climate change and the increasing frequency of drought events represent a growing challenge for forest production, affecting tree growth and productivity. Therefore, studying and identifying drought-tolerant clones that can recover and resume growth provides valuable information for selecting better-adapted clones. The purpose of this study was to determine variations in photosynthesis and morphology of four clones of Eucalyptus grandis and their interspecific hybrids after a prolonged period of water stress and a seven-month rehydration phase. The study included two Eucalyptus grandis clones (G1 and G2) and two hybrids (E. grandis × E. camaldulensis and E. grandis × E. tereticornis), with a total of 24 trees grown under controlled greenhouse conditions. These plants were subjected to two treatments: control condition (CC) and recovered condition (CR). In CR, the plants underwent a four-month water stress period followed by a seven-month rehydration phase. Photosynthetic and morphological variables were evaluated, including quantum yield of photosystem II (ΦPSII), net assimilation rate (An), stomatal conductance (gₛ), height, root dry weight, shoot dry weight, among others. Analysis of variance revealed no significant differences in maximum net assimilation between treatments, even though significant differences were observed in gₛ and some morphological variables. Clone G2 exhibited higher gₛ in the recovered condition, suggesting potential adaptation during the stress period. The quantum yield of photosystem II (ΦPSII) and other photochemical phase variables showed no significant differences during treatments, while morphological variables indicated that the control treatment outperformed the recovered treatment. This suggests that rehydration did not fully reverse the effects of water stress. In conclusion, the evaluated clones exhibited similar behavior in the measured parameters, and the recovery period enabled partial recuperation. It is suggested that shorter recovery periods and continuous measurements at the onset of rehydration could help identify early recovery mechanisms. Additionally, investigating xylem anatomical traits is recommended to gain a better understanding of gₛ variations and their relationship with hydraulic conductivity.

Estudio fitosociológico en campo natural y su relación con variables edáficas e implicancias en la respuesta a la historia de manejo del campo

Pablo Andrés Cristiano Rejal — 2025-03-28

The present work was carried out at the Mario A. Cassinoni Experimental Station of the Faculty of Agronomy - University of the Republic, located on National Route No. 3 Gral. José Gervasio Artigas, kilometer 363, in the department of Paysandú, Uruguay. This study was developed on two paddocks: paddock 13, which covers 38 hectares of re-established natural field, and is subjected to an experiment with continuous and rotational grazing methods with different levels of forage supply; and paddock 18, which covers 36 hectares of virgin natural field and is under grazing exclusion for a period of 6 months. The objective was to study the association between the plant communities of a natural field and the different environmental factors, such as the types of soil present, the history of field management, and the implication of the different grazing management used. To achieve this, a survey of the botanical composition was carried out, using the surface method with systematic sampling by means of a 1 m² square, where the cover of the identified species, bare soil, mulch, dry debris and feces was subjectively estimated in terms of absolute abundance. A total of 301 samples were taken between both paddocks. The soil types present are Brunosols, Planosols, Lithosols, Gleysols and Solonetz, which are found in similar proportions in both paddocks. For the analysis of the results, spreadsheets with information matrices were used to perform a statistical analysis. InfoStat statistical software was used, applying multivariate and univariate descriptive techniques (ANAVA) and Tukey mean comparison tests with significance levels of 10%, 5% and 1%. A total of 207 species belonging to 39 families and 13 tribes were recorded for the Gramineae family. The results show different trends for the variables analyzed according to the factors evaluated. The botanical composition at different hierarchical levels and the components of the total cover observed are determined and conditioned by the history of field management and edaphic characteristics. At the same time, there are trends in behavior according to the factors analyzed at the level of species, families, tribes and the different groupings of plant communities. Plant diversity was evaluated through biological diversity indexes, measured in terms of specific richness, Shannon-Wiener index, Simpson index and Pielou's equity index. The results indicate that the virgin field presents greater richness, diversity and equity, with less dominance, compared to the re-established field. This suggests that, after a long period of tapestry intervention in a natural field, the situation of a virgin field is not completely recovered. In terms of soil types, the Solonetz, despite not having the greatest richness, shows the greatest diversity, the least species dominance and therefore the greatest equity. The plant diversity of the natural field is characterized by a great functional complexity that is strongly related to environmental factors and their variations.

Utilización de drones en la estimación de parámetros para la gestión de sistemas pastoriles

Juan José Secco Regusci — 2025-03-28

In Uruguay, meat and milk production primarily comes from pastoral systems, whose productivity improves with efficient forage management. This requires understanding of forage availability and planning its use. This study aimed to estimate forage availability, height, and the number of leaves per tiller using a DJI Phantom 4 Multispectral drone and the Normalized Difference Vegetation Index (NDVI). The experiment, conducted in winter on perennial ryegrass and ryegrass with plantain pastures at the Southern Regional Center of the Faculty of Agronomy (Udelar), included two stages: calibration and practical application. During the calibration stage, forage height was measured using a rising plate meter (RPM) and a graduated ruler, alongside recording the number of leaves per tiller and biomass. Sampling was carried out weekly. For sampling, thirty 0.17 m² quadrats were placed using the double sampling technique. A total of 420 quadrats were sampled over 14 sessions. Simultaneously, drone flights were conducted, and the average NDVI of each quadrat was calculated using Agisoft Metashape Professional and QGis software. Simple linear regressions revealed the following correlations: R² between height measured with RPM and biomass was 0.69; R² between height measured with the graduated ruler and biomass was 0.75; R² between biomass and NDVI was 0.48; R² between height measured with RPM and NDVI was 0.37; and R² between height measured with the graduated ruler and NDVI was 0.46. These regressions enabled the calibration of the drone to estimate both biomass and forage height through NDVI. However, no relationship was found between the number of leaves per tiller and biomass, nor between the number of leaves per tiller and NDVI. With the calibration established, biomass estimated through the drone's weekly flights was compared to biomass estimated by an indirect determination device (C-Dax). This comparison revealed an average overestimation of 58% by the drone relative to the C-Dax. Nonetheless, the drone accurately represented the growth behavior of the pastures, which was encouraging. Additionally, forage availability before grazing and residuals after grazing were estimated using the drone, the C-Dax, and the RPM. The results were promising, demonstrating that the drone can be incorporated into the estimation of disappeared forage in plots, which would be useful in pastoral systems. The drone's ability to estimate forage height before and after grazing was also evaluated against the RPM. Results showed that the drone was a good estimator of height, with fewer overestimations than the RPM. Finally, spatial maps of biomass and height estimated by the drone were generated, offering visual representations of biomass and serving as valuable tools for monitoring and decision-making.

Impacto de la rotación, escarificado y riego sobre el rendimiento del cultivo de soja y propiedades físicas del suelo en sistemas arroceros

Manuela Barros Valenti — 2025-03-27

The main objective of the present research was to evaluate the impact of crop rotation, vertical tillage (chisel plow) , and irrigation on soybean yield and soil physical properties in rice farming systems in Uruguay. The study was conducted in a long-term rice rotation experiment at the Paso de la Laguna experimental unit of INIA, in Treinta y Tres, Uruguay (33° 16' 23'' S; 54° 10' 24'' W; 22 MASL). Two rotation systems were compared: one that includes pastures (Rice-soybean-pasture) and another with continuous agriculture (Rice-soybean). Both rotations have all their phases present each year and are replicated three times in space. The treatments evaluated in each rotation were: vertical tillage, irrigation, vertical tillage + irrigation, and a control, with direct seeding under dryland conditions. During the soybean growing cycle, various crop variables (population, NDVI, coverage, SPAD, height, biomass, yield components, and yield) and soil variables (residue, penetration resistance, infiltration, and wheel traffic) were measured.

The study occurred under particular climatic conditions, with excessive precipitation and a late sowing date, which resulted in reduced solar radiation during the growing cycle. In this case, the excess water may have masked the beneficial effect of irrigation. Nevertheless, irrigation treatments performed better in several of the crop variables assessed. The results indicate that chisel plow reduces penetration resistance and improves water infiltration. Furthermore, it was observed that the physical improvements from chisel plow in the pasture rotation were smaller but more stable over time. However, no significant differences were observed between rotations, which could be attributed to the sustained implementation of good management practices in the continuous agriculture system, such as direct seeding and the inclusion of cover crops. In this evaluation, no significant differences in soybean yield were observed between treatments or rotations.

Efecto de los cultivos de servicio leguminosa y gramínea en la productividad del maíz a largo plazo

Pedro Aitor Larramendy Trujillo — 2025-03-27

The agricultural intensification in Uruguay has caused erosion and nutrient loss problems due to the replacement of the agricultural-pastoral system with continuous cropping. Cover crops (CC), sown to provide ecosystem services, are a key strategy to mitigate these problems and improve agricultural sustainability. This study analyzes the long-term effect of CC and nitrogen fertilization on maize yield in a 13-year trial. The aim of this study is to evaluate the effect of cover crops and different levels of nitrogen fertilization (0 and 50 kg N ha⁻¹) on maize yield in a long-term no-till system. Functional groups of CC (legumes and grasses) and bare fallow are considered. The trial was conducted at the Dr. Mario A. Cassinoni Experimental Station (Paysandú) using a randomized complete block design with split plots. Nine treatments were evaluated (eight CC and one fallow control) along with two levels of nitrogen fertilization (0 and 50 kg N ha⁻¹). Maize yield was measured from 2007 to 2019. Analysis of variance (ANOVA) and mixed models were used to determine the effects of CC, N rates, and their interaction, classifying years as "good" or "poor" based on historical average yield. The results indicate that CC significantly affected maize yield, especially legumes, which increased yield compared to fallow and grasses. Nitrogen fertilization had a greater effect from the fifth year of the trial, reflecting the loss of the soil's N-supplying capacity. Grasses, due to their high C/N ratio, caused N immobilization, negatively affecting maize yield. The agronomic efficiency of N was higher in grasses during favorable years and in legumes during poor years. The relative yield decreased over time in fallow, while legumes showed a positive trend with N addition. Legume CC managed to increase maize yield thanks to their N contribution, even in years with lower maize yield potential. On the other hand, grasses showed greater agronomic efficiency of N in favorable years, although they limited long-term yield due to their high C/N ratio. The response to nitrogen fertilization increases as continuous agricultural use intensifies.

Evaluación del rendimiento de materia seca en festuca bajo pastoreo directo, con diferentes manejos de riego

Federico Vignolo Haro — 2025-03-20

Supplemental irrigation is an alternative to promote the increase and stability of pasture yield, especially in the context of increasingly frequent forage crises caused by the annual variability of precipitation and the low water storage capacity of our soils.

In a context of growing irrigation capacity in Uruguay, it is essential to define technical coefficients for the proper management of irrigation in pastures, which will achieve improvements in productivity while ensuring the sustainability of natural resources.

Two irrigation thresholds for fescue under grazing conditions were used to determine whether greater depletions of available soil water content resulted in better utilization of precipitation, while ensuring that dry matter production did not decrease.

The incorporation of irrigation produced twice the dry matter compared to rainfed conditions in a particularly dry year, where precipitation was the lowest in the last 30 years.

Using higher irrigation thresholds, around 65% depletion, seems to be better than allowing only 30% depletion, as there were no differences in annual dry matter production.

The total water consumed and the irrigation water used over the study year were practically the same between both treatments. In the frequent irrigation treatment, watering occurred more than three times compared to the spaced irrigation, which has operational implications and energy cost considerations.

Aplicaciones selectivas de herbicidas para el control de malezas en el barbecho

Nicolás Alfredo Berretta Freitas — 2025-03-14

Recent developments in agriculture have been closely linked to technological advancements aimed at increasing efficiency. In the application of pesticides, innovative technologies such as selective applications have emerged, aiming to minimize production costs as well as the environmental impact of pesticide use. The objective of this study was to evaluate the selective application of herbicides using Weed-it technology, comparing it with traditional methods in terms of its effects on deposition, weed control, costs, and the reduction in herbicide quantity applied per unit area. To achieve this, three experiments with specific objectives were conducted at the Mario Alberto Cassinoni Experimental Station (EEMAC), Faculty of Agronomy, Udelar. The treatments combined different equipment configurations, including two sensitivity levels for weed detection (1 and 3) and two nozzle spacings (100 and 200 mm), in comparison with total area application. In the first experiment, weed control was evaluated. The second focused on analyzing herbicide consumption for each configuration used. The third aimed to quantify product deposition on target weeds under the same configurations. The control of grass weeds did not show statistically significant differences between treatments 3 (200 mm nozzle spacing with maximum sensitivity) and 4 (200 mm nozzle spacing with medium sensitivity) compared to the control treatment. For broadleaf weeds, no significant differences in control were observed among the treatments evaluated, although treatment 3 (200 mm nozzle spacing with maximum sensitivity) showed a trend toward better performance. This suggests that, for the development of the weeds studied, the sensitivity of the equipment did not affect the control outcome. On the other hand, increasing the sensitivity of the equipment resulted in higher herbicide consumption and reduced economic savings. Regarding deposition, no interactions were identified when analyzing deposition in grass weeds and broadleaf weeds separately. However, when analyzed collectively, the highest deposition was observed in the total area application treatment, with no significant differences compared to Weed-it treatments using the widest nozzle spacing configuration.

Selección de familias e individuos en prueba de progenie de Eucalyptus grandis W. Hill Miden en la Estación Experimental Bernardo Rosengurtt (E.E.B.R)

Lorenzo Porteiro Piacenza — 2025-03-07

This study refers to a progeny test of Eucalyptus grandis W. Hill ex Maiden at the Bernardo Rosengurtt Experimental Station (E.E.B.R.). The objectives include evaluating the growth and performance of the species to identify superior genotypes in terms of productivity and quality. Dendrometric variables such as diameter at breast height (DBH), total height, and individual real volume were measured. The genus Eucalyptus, with approximately 600 species, is fundamental to commercial forestry worldwide. In Uruguay, Eucalyptus grandis is one of the most widely used species due to its rapid growth and high-quality wood. The original trial was conducted with 119 families (from six seed sources) under a randomized complete block design (RCBD), consisting of nine blocks and five individuals per family/block. Due to high mortality, a set of criteria was established in this study to determine the inclusion of blocks and individuals in the genetic analysis of the trial. The results showed significant genetic variability among the evaluated families, allowing for the selection of superior genotypes. The total volume for the 2.7 ha of the blocks considered in the trial was 1,868.59 m³. Additionally, the volume per hectare reached 692.07 m³, representing a 73.73% increase compared to the last recorded evaluation in 2004. The assumed additive genetic variance was generally low in the trial, representing only 6.93% of the average phenotypic value of the individuals. This was associated with limitations imposed by high mortality and adverse environmental conditions. However, the trial demonstrated adequate precision in estimating genetic parameters. Families 79, 97, and 72 stood out in terms of volume, presenting the highest phenotypic values, with 1.765, 1.725, and 1.679 m³ tree⁻¹, respectively. In contrast, families 64, 77, and 15 exhibited the lowest volume values, with 1.191, 1.189, and 1.186 m³ tree⁻¹, respectively. The best families and individuals were identified to contribute to forest genetic improvement in Uruguay, proposing selection and genetic management strategies to maximize genetic gains and conserve diversity.

Efecto de la suplementación invernal con grano de lupino o afrechillo de arroz sobre la performance de terneras pastoreando campo natural

Guillermo Apa Olivera — 2025-02-21

The objective of this work was to evaluate the response to daily supplementation with lupine grain and rice bran during the winter, in conventionally weaned calves grazing natural fields. This response was evaluated in terms of live weight gain and weight at the end of winter, and efficiency of supplement use. Additionally, as interpretive variables, the effect of supplementation with these foods on forage utilization and ingestive behavior of grazing animals was characterized. The experiment was carried out in a commercial establishment, located in the Salto area, east of the department of Salto (geographic coordinates 31º 29'50'' South latitude and 57º19'06 West longitude). The experimental area was 31.5 hectares, which was subdivided into 3 plots of 10.5 hectares. The experimental work lasted 71 days, from July 12 to September 21, 2022. 48 calves were used with an initial live weight of 158 ± 3.2 kg, which were randomly divided into batches of 3 animals. The experiment presented a randomized plot design with the animal being the repetition. In each treatment, 16 calves were used, which grazed the natural field continuously, with an adjusted load of 1.52 calves per hectare, a treatment called lupine, where there were animals that, in addition to grazing natural fields, had access to grain. lupine and another treatment called rice bran, which had access to that food. The average daily gains in live weight obtained in the Control, bran and lupine treatments were -0.2 kg/day, 0.18 kg/d and 0.30 kg/d respectively, achieving an Ec of the supplement of 4.1 to 1 with rice bran and 2.2 with 1 with lupine grain.

Estudio de caso del enoturismo y producción vitivinícola en Canelones

María Belén Santana Laurnaga — 2025-02-21

The main goal of this thesis is to generate knowledge about the winemaking activity in the department of Canelones, Uruguay, and the influence of wine tourism on said activity. The research focuses on understanding how wine production and wine tourism activities are interrelated, and how these dynamics can contribute to the economic and social development of the territory. Through a combination of surveys of local wineries and data analysis from secondary sources, patterns, challenges and opportunities in wine production and win tourism were identified. The wineries in Canelones are strongly linked to traditional family businesses, many of which come from European immigrants, mainly Italian, Spanish and French, who found favourable conditions for growing vineyards in this region. Wine production is diverse, including table wines, fine wines, sparkling and liqueur wines, and its marketing is carried out both locally and internationally. Wine tourism has emerged as a key tool for income diversification and brand promotion. Nevertheless, despite the potential of wine tourism, wineries face significant challenges such as the lack of adequate infrastructure, the need for trained staff, and better promotion and communication. Recommendations to promote wine tourism in Canelones include investing in infrastructure, training staff, developing effective marketing strategies, promoting strategic alliances and diversifying the wine tourism offer.

Microorganismos involucrados en la absorción de fósforo en la Isla Rey Jorge, Antártida

Rebeca Gonnet Rivoir — 2025-02-20

Deschampsia antarctica is one of the two plant species that have successfully to colonized and adapted to Antarctica. The interaction with microorganisms adapted to the Antarctic environment could partly explain its presence, so this work focused on studying the interactions of D. antarctica with groups of endophytic fungi and bacteria associated with the phosphorus (P) cycle. The objectives were: to evaluate the potential for mycorrhizal and DSE colonization of Antarctic soils; to determine the presence of arbuscular mycorrhizae (MA) and dark septate endophytic fungi (DSE) in roots of D. antarctica; to quantify the presence of glomalin associated proteins in Antarctic soils and to determine the number of rhizospheric bacteria solubilizing P. On King George Island, during the summers of 2019,2020 and 2021, soil and root samples of D. Antarctica were taken at two sites with contrasting contents of available P: Drake (high P) and Suffield Point (low P). Mycorrhizal and DSE colonization and easily removable glomalin (GFE) were quantified. Total aerobic heterotrophic bacteria (BHTA) and P-solubilizing bacteria (BSP) were counted from the rhizosphere of D. antarctica. The mycorrhizal potential was studied in trap culture using soil from both sites, at the Faculty of Agronomy. The presence of mycorrhizae in D. antarctica was high, 46 and 52% and that of DSE 19 and 30% in Drake and Punta Suffield, respectively, with not significant differences between sites, except in DSE. The results obtained in terms of the glomalin fraction GFE show small differences to favor of Drake (1,34 and 1,46 mg glomalin /g soil) and 1,28 and 1,13 mg at Suffield Point in 2020 and 2021 respectively. A higher BSP/BHTA ratio was found in Drake, indicating a positive relationship between P content and the presence of BSP. The presence of bacteria and fungi linked to the P cycle in Antarctica represents a possible strategy for plants to acquire this nutrient and survive in these extreme conditions.

Evaluación de alternativas de manejos en cobertura en césped deportivo

José Agustín Monza González — 2025-02-13

Sports turf surfaces, especially in Uruguay, play a fundamental role in football, the most popular sport in the country. However, poor playing field conditions negatively affect the quality of the performance, increase the risk of injuries and hinder sports performance. The specific objectives were: (i) to analyze the effect of topdressing with sand, compost and their combination on soil compaction and penetration resistance in sports fields, (ii) to evaluate the impact of treatments on turf growth and development, measured through variables such as height, density and visual quality, measured through NDVI. Field trials and bioassays were implemented under controlled conditions, using four treatments: sand (AA), compost (CC), a mixture of sand and compost (AC), and a control (T). Variables such as penetration resistance (RP), turf height and vegetation indices (NDVI) obtained through remote sensing were measured. The results indicated that treatments with compost and sand significantly reduced soil compaction, favoring root development. Compost stood out for improving the height and density of the turf, thanks to its contribution of organic matter and nutrients such as NPK. On the other hand, the combination of sand and compost presented inconsistent results due to negative interactions between the materials. This study concludes that the application of compost and sand improves both the development of the turf and the properties of the soil, while it is necessary to optimize the mixing proportions for the combined treatment. Future work is proposed to determine the ideal combinations that enhance the quality of the turf and its sustainability.

Fuentes alternativas de fósforo en sistemas agrícolas

Tomás Ciro Gallo Altieri — 2025-02-07

This work explores the use of alternative sources of phosphorus, such as pulp industry sludge, manure and hot bedding from a confined dairy farm, as an alternative to inorganic fertilizers in maize (Zea mays) production. The research addresses the need to know the impact on agricultural production of replacing inorganic fertilizers with alternative sources of phosphorus, which represent an opportunity to reuse existing residues. In addition, their use could reduce dependence on chemical inputs, promote a circular economy by valorizing these wastes, and contribute to mitigating the associated environmental impacts. The main objective was to evaluate the potential of these organic amendments to maintain maize yields and improve soil nutrient availability, focusing on phosphorus. In addition, the impact of these amendments on phosphorus and sediment export in surface runoff was analyzed because of its relevance to environmental impact. During the 2023/2024 summer harvest, a trial was conducted in a randomized complete block experimental design with eight treatments and three replications, including paired controls to correct for variations in field conditions. Variables analyzed included grain yield, accumulated aerial biomass, soil, plant, and grain phosphorus concentrations, and phosphorus losses in surface runoff and sediment runoff. The treatments included amendments applied at equal doses of phosphorus and, in the case of sludge, at double doses. The results indicated that on soils with high initial phosphorus levels, the application of organic amendments had a limited effect on biomass and grain yield. At the same time, phosphorus stratification was evident in the topsoil layer (0-2.5 cm), which increases the risk of surface runoff losses. While no notable discrepancies were identified in phosphorus concentrations in runoff water, the treatments with sludge and hot bed exhibited elevated values, suggesting a heightened susceptibility to contamination. Conversely, the concentration of sediment in the runoff water did not demonstrate substantial variations between treatments. However, both phosphorus and sediment concentrations in runoff water exhibited notable fluctuations between precipitation events, influenced by the crop's phenological stages and the volume of precipitation.

Relación entre Colletotrichum spp. y la muerte regresiva de ramas de cítricos

María Florencia Pereyra Farina — 2025-02-04

In citrus plantations in the south of the country associated with mechanical pruning, branch necrosis was detected in a generalized manner in the frames of trees in full production. To determine the possible causes, isolations were made from affected branches of lemon lisbon (Citrus limon) and Afourer mandarin (Citrus reticulata Blanco). Subsequently, the fungal isolates obtained were identified by morphological and molecular techniques, selecting representatives of the different morphological types observed. Pathogenicity tests were performed on detached lemon branches and flowers under controlled conditions to evaluate the relative aggressiveness of each representative and to be able to compare between them. In addition, the susceptibility of branches of different thicknesses was compared. The maximum amount of disease, the rate of symptom development and the area under the disease progress curve (AUDPC) were evaluated. From the symptoms observed in the artificial inoculations, isolations were made that confirmed the presence of the same inoculated fungi. This allowed us to comply with Koch's postulates and establish a causal relationship between Colletotrichum gloeosporioides s.s and branch necrosis in Citrus limon.

Evaluación y caracterización de germoplasma de arroz en comparación con variedades comerciales

Natalia Miraballes Maza — 2025-01-10

A trial was conducted at the Paso de la Laguna Experimental Unit of INIA Treinta y Tres during the 2022-2023 growing season. The objectives were to evaluate and characterize imidazolinone-resistant rice materials from the INIA Rice Breeding Program to identify varieties with unique agronomic and milling traits for pre-commercial scale evaluation. Two independent trials were carried out, sown on different dates: early sowing (October 5) and late sowing (November 7). Eleven experimental lines and four commercial checks were assigned to randomized complete block designs with four replicates. The agronomic traits evaluated included grain yield and its components, days to flowering, plant height, and disease incidence. Milling quality parameters included head rice yield, whole grain percentage, and chalkiness percentage. Additionally, seed dormancy was evaluated. The trials had an average yield was 10.9 t/ha, while the reference check (GURI INTA CL) achieved 10.3 t/ha. Some materials exceeded 12 t/ha in productivity, including the hybrids INOV FP and XP 113 FP, as well as the cultivar CL 19244. Promising lines such as CL 19258, CL 19246, and CL 19231 showed significantly higher yields compared to the check, particularly in the late sowing (EP2), with increases of 12%, 14%, and 17%, respectively. Milling quality parameters generally surpassed the commercialization base for head rice yield and whole grain percentage. However, chalkiness levels were generally high, with the cultivar CL 1294 standing out in this parameter. The cultivar CL 19265 demonstrated good overall milling quality values. The material CL 19263 did not differ in yield from the check but showed higher chalkiness in EP2, while CL 19219 exhibited superiority in chalkiness in both sowing periods. The seed dormancy of some materials was short, with germination probabilities at 5 days exceeding 0.8 in materials CL 19220, CL 19246, and CL 19219, while at 14 days, it was 0.14 and 0.34 for the reference check and CL 19265, respectively.

Efecto de la geo-nivelación sobre el rendimiento de soja y la dinámica de agua y nutrientes del suelo en sistemas regados del este

François Jacques Anciaux Esquiros — 2024-12-27

Flooding issues in soybean cultivation negatively affect the proper development of plants and can even cause their death. For this reason, techniques such as land leveling are employed to eliminate affected areas and achieve an appropriate slope that facilitates proper water drainage. The main objective of this study is to evaluate the impact of land leveling in cut, fill, and neutral situations, analyzing its effect on the physical and chemical properties of the soil, as well as its influence on soybean yield under sprinkler irrigation systems in the eastern region of the country. To achieve this, the study environment was characterized by a climatic description of the evaluated period, along with quantifying the water infiltration rate in the soil of the field. A statistical model with blocks was defined based on the slope phase, and results were subsequently analyzed using 36 sampling points evenly distributed across the three blocks within the 27.24 hectares of the field. These evaluations included soil density, seedling survival, crop biomass, and grain yield. Additionally, a chemical analysis was conducted for each point, including pH, organic matter (OM), cation exchange capacity (CEC), base saturation (%BS), phosphorus (P) concentration, exchangeable potassium (K int), sodium (Na), magnesium (Mg), and calcium (Ca). All samples were taken during the harvest following the smoothing operation. The results of the analyses show that with a soil movement of 76.6 m³/ha and a cut/fill ratio of 1.2, no significant differences were observed in soil properties or crop yield. The fill treatment showed variability in plant development, attributed to the effect of flooding, which was partially mitigated by land leveling. In conclusion, these results suggest that proper management of land leveling, along with optimal irrigation control, can improve production conditions in soils with very low slopes, enhancing the sustainability of soybean production in the region.

Caracterización química de la madera de híbridos interespecíficos entre Eucalyptus grandis y Eucalyptus dunnii

Matias Luna Fernández — 2024-12-20

In Uruguay, Eucalyptus grandis and Eucalyptus dunnii are key species in pulp production. This study focused on the chemical characterization of wood from interspecific hybrids between these species to assess their suitability for pulp production. A total of 198 wood samples were collected from 29 families distributed across two trials, involving two cross types: E. dunnii x E. grandis and E. grandis x E. dunnii. Several chemical analyses were conducted to determine the content of extractives, calcium, ash, and moisture. Extractive content was measured using a Soxhlet apparatus with ethanol as the solvent, while calcium and ash content were determined through muffle furnace digestion at 500 °C. Descriptive analyses were performed for these variables, followed by the application of linear models to evaluate the effects of factors such as family, cross type, and trial on the chemical parameters. Tukey's tests were applied to compare means, and Pearson correlation analyses were conducted between these variables and wood quality traits, including pulp yield and basic density. Significant differences were found only between cross types for calcium and ash content. Rankings by family were created select the best families for these parameters, revealing that hybrids with E. dunnii as the maternal parent exhibited higher calcio and abs contents, while hybrids with E. grandis as the maternal parent showed lower levels. Although no significant effects were found for extractives, rankings by family were also performed. The data analysis suggested a potential relationship between cross type and extractive content, where E. dunnii x E. grandis hybrids tended to cluster around lower and intermediate levels, while E. grandis x E. dunnii hybrids showed a higher proportion of families with elevated levels. The correlation between pulp yield and extractive content was negative (-0,27). Conversely, the correlation between pulp yield and calcium content was 0,18, indicating a weak relationship.

Prospección de especies de Calonectria en viveros forestales de Uruguay

Florencia Scarabino Aprile — 2024-12-20

Over the past three decades, the forestry sector in Uruguay has experienced a significant growth, consolidating itself as the second largest agricultural export sector, with Eucalyptus being the most planted genus in the country. Nursery production is the first stage of the forestry sector, where plant production is exposed to various pathogens attacks. Species from the genus Calonectria cause diseases in nurseries such as damping-off, root rot, leaf spot, and stem canker, leading to significant economic losses. The aim of this study was to survey and identify Calonectria species present in Eucalyptus nurseries in the northern and central eastern regions of the country, based on molecular and morphological characterization techniques. Visits were made to three nurseries and a total of 123 samples were collected, including symptomatic Eucalyptus spp. seedlings, soil beneath benches, irrigation water, first-use substrate, and sand tray, covering all nursery stages. The pathogen was found in 11% of the samples, yielding resulting in a collection of 17 isolates being that were molecularly identified, together with 15 additional Calonectria strains previously isolated from other study, using the elongation factor and beta-tubulin gene regions. Based on the phylogenetic analysis, 24 isolates belong to the Calonectria candelabrum complex, and eight belong to Ca. cylindrospora complex. Within the former, all isolates were identified as Ca. pauciramosa, while the isolates from the latter are grouped into two clades (five and three), different from each other and from other known Calonectria species. This suggests that these could be new, undescribed species. Complementary, the morphological characterization revealed considerable diversity among Ca. pauciramosa isolates, whose structures matched descriptions reported in the literature. These findings are an important precedent for the phytosanitary status of the country´s forestry complex.

Estudio de biología y control de malezas gramíneas estivales

Martín Aceredo Boz — 2024-12-20

This study aimed to investigate the biology of three summer weed species and assess their control using various herbicides. To achieve these objectives, three experiments were conducted in March 2021.

In the first experiment, seeds of Echinochloa colona, Echinochloa crus-galli, and Chloris virgata were sown at four different planting depths, with vetch residue, rye residue, and without residue. The second experiment involved sowing the same species at a uniform depth and applying eight pre-emergent herbicides, along with a control treatment. In the third experiment, the plants were allowed to develop three true leaves before being thinned to four plants per pot, at which point six post-emergent herbicides and a control treatment were applied.

All experiments were conducted at the Mario Alberto Cassinoni Experimental Station (EEAC), Faculty of Agronomy (Udelar), located in the department of Paysandú, Uruguay. After planting and herbicide applications, emergence evaluations were performed to monitor plant development in Experiment 1, and to assess herbicide control efficacy in Experiments 2 and 3.

The results showed that shallow planting depths in Experiment 1 negatively impacted the species' emergence. For the post-emergent herbicides, two displayed poor control performance, while only one herbicide in Experiment 3 failed to control the target weed species effectively.

Efecto de los genes de vernalización VRN1 y fotoperíodo PPD1 sobre la fenología y los componentes de rendimiento en trigo

Ramiro Ahunchain Crusich — 2024-12-20

Wheat (Triticum aestivum L.) is an essential global crop due to its contribution to food security and its ability to adapt to diverse environmental conditions. In Uruguay, it is the main winter crop, with an average annual production of 1.13 million tons, highlighting its economic and productive significance. This study analyzes how the Vrn-11 and Ppd-1 genes, which regulate vernalization and photoperiod respectively, influence wheat phenology and yield components. Nineteen genetic materials, classified according to their allelic combinations for these genes, were evaluated across four sowing dates at INIA La Estanzuela, using a randomized incomplete block design with two replicates. Variables measured included growing degree days to first node, heading, and physiological maturity, as well as yield, number of spikes, grains per spike, and thousand-grain weight. Data were analyzed using mixed linear models to adjust means and determine significant differences among phenological groups.

The results showed that winter genotypes had slower development but achieved high yields in early sowings, making better use of initial climatic conditions. Spring genotypes insensitive to photoperiod stood out for their phenological stability and high yields across all sowing dates, demonstrating great adaptability. In contrast, spring genotypes sensitive to photoperiod exhibited longer cycles, better phenological adjustment, and greater stability in late sowings, reflecting robust adaptation to changing environmental conditions. Additionally, a positive impact of recent genetic improvement was observed, with materials showing higher productivity and better adaptability to variable conditions. Environmental factors such as radiation and temperature during critical crop stages also significantly influenced yield, underscoring their importance in crop performance.

This study emphasizes the interaction between vernalization and photoperiod genes and their importance in optimizing wheat productivity and stability in diverse environments. The selection of specific allelic combinations for these genes allows for the development of materials better suited to specific sowing dates and climatic conditions. The results provide valuable tools for breeding programs and agronomic management, essential for addressing the challenges of climate change and ensuring the sustainability of wheat production in Uruguay.

Evaluación de persistencia en mezclas forrajeras con componentes perennes estival e invernal en el norte del país

Joaquín Alonso Delgue — 2024-12-20

The incorporation and domestication of forage species of Mediterranean and continentals’ origins have been strengthened in the Uruguayan pastoral systems, nevertheless in the North of the country the low resistance of these zones limit the potential productivity. One of the native species that has features to increase its persistence of traditional forage mixtures, is Paspalum notatum. In this paper it is expected to assess if the incorporation of this species mixed with forage components such as Festuca arundinacea, Dactylis glomerata, Trifolium repens and Lotus corniculatus, generates any positive effect in the increase of longevity of these browses in the zone mentioned. In order to accomplish this goal, the contribution of each component in each mixture and the survivorship of tillers of wintry gramineaes in the corresponding mixture were measured. Simultaneously, it was possible to obtain information about the productive behavior of the native summer grass in pure sowing; these figures are scarce in Uruguay. The data was collected since 12 th December 2022 until 5 th May 2023 in order to cover the summer season; which is considered critical for wintry species; and the beginning of autumn to control the summer grass and how it enters the season which is favourable for its growth and development. The browse plot that were assessed are four: Plot 1- compound only by Paspalum notatum, Plot 2, that included Festuca arundinácea, Trifolium repens and Paspalum notatum; plot 3A compound by Festuca arundinácea, Lotus corniculatus and Paspalum notatum; and plot 3B replaces wintry gramineae of the plot 3A with Dactylis glomerata and maintains the other components. Regarding the results obtained, according to the information available, it was inferred that the summer performance of Dactylis in a mixture would be better than in a mixture with Festuca, in addition to a lower level of weed infestation in the first species. In Paspalum, a better productive performance was expected in a mixture with Festuca, and, in pure sowing, it would be expected that the pasture would reach an established population and the entire area covered. In turn, these conjectures could not be verified almost in their majority, where the only affirmation that could be verified was the stable population of paspalum in pure sowing at its third year of age.

Evaluación de un nuevo curasemilla para el control de pulgones en cultivos de alfalfa, colza, raigrás y avena y su efecto sobre la germinación y vigor de las semillas

Loana Lluberas Valcheff — 2024-12-19

This study evaluated the effect of an experimental seed treatment on seed quality and aphid control in alfalfa, canola, ryegrass, and oats. Aphids are pests that affect the productivity of these crops, especially during the establishment stage, and the use of seed treatments is key to proactively protecting crops during this phase. The main objective of the study was to analyze the impact of the experimental seed treatment on seed germination and vigor, as well as its effectiveness in controlling the following aphid species: Acyrthosiphon pisum in alfalfa, Lipaphis erysimi in canola, and Rhopalosiphum padi in ryegrass and oats.

The experiments were carried out in the laboratories of INIA La Estanzuela, using a completely randomized design with repetitions. Different doses of the experimental seed treatment were applied and compared with registered commercial products. Germination and vigor parameters were measured, along with the effectiveness of the seed treatment in controlling aphids under controlled conditions.

The results showed that the experimental seed treatment had no negative effects on germination or vigor in any of the evaluated species, like the commercial products. In terms of aphid control, the experimental seed treatment was effective in alfalfa, canola, and ryegrass, reducing aphid populations to levels comparable to or superior to those of the commercial treatments. It is concluded that this experimental seed treatment is a promising option for integrated pest management, offering an efficient and sustainable solution without compromising seed quality.

Actualización de la base de datos de condición corporal en la raza Angus de Uruguay

Matías Carreño García — 2024-12-19

The objective of this work was to update the existing cond_corp database for the Aberdeen Angus breed. For this purpose, images were captured using cellular phones, which were then classified to form the new database of the program.

The field work was carried out at the Los Macachines farm, located near the town of Tupambaé, in the department of Cerro Largo. A total of 186 Angus cows from two different lots were used. An average of 6.45 photos were taken per cow, recorded individually while they were in the stump box.

Subsequently, from the desktop, the photos were evaluated and each was assigned a body condition score using a scale of 1.5 to 6.5 with intervals of 0.25 units. The images were organized into 20 folders and incorporated into the cond_corp program, totaling 186 new photos. For the creation of the new visual appreciation primer, representative images were selected for each score, adding the intermediate scores (2, 2.5, 3...6).

The updating of the database and the visual appreciation chart provides valuable tools to help producers in making decisions in the management of their breeding herds.

Ajuste de modelos de crecimiento y estudio del efecto de la oferta de forraje y del grupo genético de las vacas sobre la evolución de peso vivo de sus hijas hasta los 26 meses de edad

Federico Rubio Villasante — 2024-12-19

Since 2007, an experiment has been carried out at the Professor Bernardo Rosengurtt Experimental Station to evaluate the effect of modifying the supply of natural pasture forage on the productive and reproductive performance of breeding cows of various genetic groups. A factorial design was used that combined two levels of pre- and postpartum forage supply: High and Low, with two levels of the genetic group factor: Purebred and Crossbred, resulting in the following treatments: High Crossbred, High Purebred, Low Crossbred and Low Purebred. The objective of this particular work is to evaluate the effect of the forage supply with which the cows were managed during the pre- and postpartum and their genetic group on the live weight of their daughters from birth to 26 months of age. A database consisting of 2373 live weight records was used, corresponding to 182 heifers, daughters of the cows managed in the aforementioned experiment, which were born between 2007 and 2014. Considering the live weight of the heifers as the variable of interest, a mixed model was formulated in which the forage supply at which the heifer's mother was managed, the genetic group of the mother, the age of the heifer, as well as the double interactions between the age of the heifers and the other two factors mentioned above were included as fixed effects. The heifer and the year of its birth were considered as random effects. Based on this model, the forage supply assigned to the mothers of the heifers, as well as the interactions between age and supply and between age and the genetic group of the mother, had a significant effect on the live weight of the heifers, while the genetic group of the mother did not. Taking into account the factors included as fixed effects in the model, Tukey tests were performed to analyze each of them. The results of these tests showed no significant differences between the weights of the heifers at each of the ages evaluated considering, on the one hand, the levels of forage supply (high vs. low) and, on the other hand, the levels of the genetic group factor (purebred vs. crossbred). Regarding the individual effects analyzed, significant differences were detected between the levels of forage supply, with heifers from cows managed at a high forage supply being heavier than those from cows managed at a low supply (208 vs. 205 ± 5 kg). On the other hand, no significant differences were found in the average live weight of the heifers according to the genetic group of their mothers. Additionally, another mixed model was proposed with the aim of evaluating a series of statistical models that described the growth experienced by the heifers during the analysis period. This model considered the live weight of the heifers as the variable of interest and, as fixed effects, the treatment received by the mothers, the genotype of the father and the age of the heifers expressed in days. The heifer and the year of birth were included as random effects. Linear regression models (such as the first and second order models) and non-linear regression models (such as the Brody, Von Bertalanffy, Gompertz and Logistic models) were evaluated. All models showed a very high fit to the data, with adjusted r2 values around 0.93, with practically no differences regarding this coefficient between the evaluated models. Regarding the AIC and BIC coefficients achieved by these models, it was found that, within the linear regression models, the second order model was the one that presented the lowest values of said coefficients, while, within the non-linear regression models, it was the Brody model. Therefore, within the group of linear regression models, the second-order model was the model that best fit the database, while within the group of nonlinear regression models, it was the Brody model.

Evaluación del efecto climático sobre la estabilidad estructural del arbolado urbano de Montevideo

Jorge Pérez Casas — 2024-12-18

This study investigates the effects on urban trees in Montevideo of extreme weather events, particularly strong winds. The objective is to identify more adapted species, and those with less resistance in order to optimize urban management. The research combines analysis of meteorological data and the processing of reports of tree falls. The influence of the tree species and the intensity of the wind on stability is considered. The analysis characterizes climatic events, differentiating between extratropical cyclones and convective storms, to determine their differential impact on the rate of falls. The results show a significant correlation between the intensity of meteorological events and the number of fallen trees. The analysis of reports, grouped by genus/family, geographic location, and time period, identifies vulnerable species. Significant storms are analyzed, presenting wind speed data and maps illustrating the distribution of falls. Among the resistant species, Fraxinus, Platanus, Tipuana, Melia and Acer stand out, while the genera Cupressus, Pinus, Eucalyptus, and Schinus showed greater vulnerability. The presence of rain during wind events significantly increased the rate of falls. A higher probability of falls was observed in CCZs 4, 11, 17 and 18, while 6, 1, 14 and 8 showed lower rates. Seasonality also influenced the frequency of falls. The implications for the management of urban trees in Montevideo are significant. It is recommended to prioritize the planting of resilient species. It is crucial to avoid the planting of Cupressus, Eucalyptus, Pinus, Schinus and Salix due to their vulnerability and other undesirable characteristics. An inspection and monitoring program should be implemented for a regular maintenance scheme. It is necessary to investigate the causes of falls to identify factors that contribute to structural weakness. The integration of trees into urban design should ensure adequate spaces for root and aerial growth, considering their interaction with infrastructure. Awareness campaigns and training of arboricultural staff on best practices are recommended. Inter-institutional collaboration and an updated data registry are crucial for informed decision-making. Finally, additional research is suggested to delve deeper into species behavior and their adaptation to changing climatic conditions. Methodological limitations, such as imprecision in species identification and the use of meteorological data external to the study area, should be considered when interpreting the results.

Efecto de diferentes niveles de defoliación mecánica y causados por Rachiplusia nu en el rendimiento de soja

Guillermo Daniel Beasley Lomazzi — 2024-12-18

Soybean provides 60% of the plant-based protein consumed worldwide and is the main summer crop grown in Uruguay. Rachiplusia nu (Guenée) (Lepidoptera: Noctuidae) is a common defoliating pest in soybean crops, whose damage may affect yield due to the reduction of photosynthetically active leaf area. The objectives of this study were to: a) determine whether the effect of defoliation on soybean yield varies between damage caused by R. nu larvae and mechanical defoliation; b) quantify total yield, the number and weight of grains in plants subjected to different levels of defoliation caused by R. nu larvae at various phenological stages. A field experiment was conducted from November 2023 to May 2024 at the "Dr. Mario A. Cassinoni" Experimental Station on a soybean crop (GÉNESIS 6301). Following a completely randomized design, exclusion cages were placed on individual soybean plants, which reached different defoliation levels generated at different phenological stages (V5, V10, and R5) by infesting R. nu larvae or inflicting mechanical cutting with scissors. The achieved defoliation was visually estimated, and plants with a maximum of 2% defoliation were considered as controls. The origin of the defoliation (larvae or mechanical cutting) did not result in significant differences in yield within the evaluated ranges and timings (46–60% in V5 or 21–45% in R5). These results validate the economic injury thresholds established in previous studies using mechanical cuts, suggesting that there would be no specific response in plant yield to herbivory or its simulation through mechanical cutting. Regarding different levels of defoliation, at the V5 phenological stage, plants with defoliation levels greater than 45% showed reduced yield compared to control plants, having a yield loss of 22%. At V10, plants that experienced the maximum level of defoliation (80%) showed no yield differences compared to controls. At the R5, the number of grains was lower from the 10-20% defoliation range, while yield decreased from the 21-45% range, in which yield loss was 19%.. These findings highlight the high tolerance of soybean crops to defoliation under non-restrictive water conditions and justify the need to reduce insecticide, promoting an integrated and sustainable pest management approach.

Distribución geográfica y diversidad morfológica de la especie Eugenia Involucrata DC. en Uruguay

Agustín Giagnacovo Bustamante — 2024-12-18

Eugenia involucrata (Myrtaceae) is a woody species which naturally occurs in Argentina, Bolivia, Brazil, Paraguay, and Uruguay. Commonly known as ‘Cereza de monte’, ‘cerejeira do mato’ or ‘cerella,’ it is a plant with promising characteristics for use as an ornamental or domestic fruit tree, and with high potential for commercial plantations. Its fruits are dark red to violet berries with a persistent calyx, containing one to seven seeds. They have a sweet and pleasant flavor, making them attractive for fresh consumption and culinary preparations. The objective of this study was to gather information about E. involucrata available in national herbaria, identify the natural distribution of wild populations of E. involucrata in Uruguay and assess its phenotypic variability. Herbaria from MVFA, MVFC, MVFQ, MVJB and MVM were visited. Between October 2020 and November 2021, surveys were performed along the shores of the Cuareim River. During flowering, herbarium samples were collected from up to 22 plants per population to evaluate 31 morphological variables. In the fruiting stage, up to 30 fruits were collected per sampling point to assess 12 variables. Nine herbaria samples were found, seven coming from wild forests, without reproductive structures. Wild populations were confirmed in five out of the six explored sites in the Artigas department, mainly composed of more than 20 plants, along the Cuareim River and Tres Cruces Stream. Mean, standard deviation, and coefficient of variation were estimated, and multivariate analysis was performed to identify diversity within and among populations. Regarding vegetative variables, significant differences (ANOVA; p < 0.05) were found between populations only for petiole length. Among reproductive variables, significant differences were observed in sepal width, petal width, petal length-width ratio, stamen whorls number, and ovary diameter and height. Fruit variables showed significant differences in mass, height, diameter, fruit pulp proportion, and calyx length. In multivariate statistics, no significant differences were found. However, trends highlighted one population with characteristics related to larger fruit size, fewer seeds, and a higher fruit pulp proportion. This study provides the first assessment of morphological diversity in wild populations of E. involucrata in Uruguay. It confirms that the species reaches its southernmost distribution area in Uruguay. This highlights the importance of studying and conserving this native phytogenetic resource, whose external appearance and good taste promise favorable consumer acceptance.

Efecto del fuego sobre micorrizas y hongos endófitos radiculares en especies de campo natural

Jorge Adrian Muguruza Mateos — 2024-12-17

The Uruguayan territory is part of the Río de la Plata grasslands region, where extensive cattle ranching represents the most important agricultural activity. In some areas of the country, controlled burning is employed to improve forage availability by altering vegetation structure and promoting regrowth. The objective of this study was to understand how burning and grazing influence the presence of arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) in a group of native grassland plant species with varying responses to fire. An experiment examining the interaction of fire and grazing is underway in the Quebrada de los Cuervos y Sierras del Yerbal Protected Landscape, within an area dominated by Saccharum angustifolium ('paja estrelladora'). Plants from five species with varying responses to fire were collected: Stenachaenium megapotamicum and Hypoxis decumbens (favored), Saccharum angustifolium and Acanthostyles buniifolius (tolerant), and Solidago chilensis (sensitive). Samples were taken across three treatments: exclosure without burning (control), grazed and burned (one-year post-burn), and grazed and recently burned (two months post-burn). High colonization by AMF was observed across all treatments and species, with an occurrence rate exceeding 80%, while DSE had an occurrence rate above 72%. However, the presence of arbuscules was below 40%, and coils were observed in less than 5% of cases. Fire and grazing significantly influenced the presence of mycorrhizae, with varied effects depending on the plant species; some were favored while others were reduced by these factors. S. megapotamicum, which benefits from burning, exhibited the highest levels of mycorrhization, including the presence of arbuscules and vesicles. H. decumbens, another favored species, recorded the highest presence of coils. In favored or tolerant species, control treatments consistently displayed higher values than any burned treatments whenever differences were observed. Conversely, the sensitive species S. chilensis showed an opposite pattern, suggesting a promising direction for future research. This thesis provides novel data on plant-root fungi interactions in areas affected by fire and grazing. It highlights the need for further exploration of the effects of fire and its interaction with grazing on these interactions, as well as on potential impacts on plant populations.

Efectos de la reconversión varietal en la vitivinicultura uruguaya

Emiliano Rodríguez Machado — 2024-12-17

The varietal viticultural reconversion began in Uruguay in 1970 in a private manner and in 1990 the State established and consolidated it through the Pilot Program of Reconversion of Vineyards and subsequently the Program of Reconversion and Development of the Farm. Uruguayan wine experienced a renewal of its vines and its varieties, as well as its handling. Both the wine industry and the marketing of the product have been transformed, so the reconversion involves the three production phases: the primary, the industrial and the commercial. As a result of this process, Uruguay began producing fine wines in the domestic market and embarked on exportation.

The objective of this work was to understand the effects of the reconversion in Uruguayan viticulture through the opinion supported in the actuality of the same winemakers who experimented with it in its companys. It was intended to know the judgement that the process holds in general and its consequences, as well as evaluating the benefits of the same and discussing the paper when unpacking the products.

Semi-structured interviews were carried out with twelve wine producers in the reconversion process, appreciating the distinct production sizes and the two main winemaking regions of the country: Canelones/Montevideo and Colonia, with the aim of knowing their experiences and opinions regarding the historical process, its consequences and the actuality of the sector.

All the respondents responded in a similar way to the majority of the points, without encountering differences at the level of the geographical region or scale as the products.

There was consensus among those who thought that the reconversion was an success. This was what allowed Uruguayan viticulture to remain competitive in the face of the growing import of wines given the processes of economic opening. There is an increase in national wine sales and an increase in exports.

Although the disappearance of many producers, especially the smaller ones, is a fact, the interviewees did not blame the process for this, and sayed that anyone was disabled to reconvert. The bibliographic review shows that the disappearance of the products, mainly in the lower scale extracts, had begun previously.

The high production costs and the competition with imported wines are now presented as the main problems of the sector.

Estimación de propiedades físicas y anatómicas de árboles en pie de Pinus taeda utilizando tecnologías no destructivas

Lucía Belén Revetria Martínez — 2024-12-16

Compression wood (CW) is formed in gymnosperms in the lower part of branches and inclined trunks as a biomechanical adaptation mechanism, which generates a negative effect for the industry. Therefore, it is essential to develop methodologies to detect the presence of CW in standing trees to prevent this material from reaching industrial processes. With this objective, nondestructive testing (NDT) for the early detection of CW in standing trees of Pinus taeda was evaluated. Eighteen trees were selected according to phenotypic criteria, and measurements were made using a sonic tomograph (Fakopp), ultrasound (Sylvatest) and resistograph (penetrometer). In addition, physical properties were determined and a visual evaluation of the presence of CW was performed. The results indicated that the resistograph is the equipment that presents the highest correlation with CW; however, it is advisable to use these techniques together, since a complementarity between them has been observed. It is necessary to continue with studies to identify the best combination of NDT and reduce the error of the model (decision tree) proposed for the estimation of CW in standing trees.

Comportamiento enológico de Arinarnoa, Marselan y Tannat (Vitis vinifera. L.) bajo distintas alternativas de vinificación en tinto

Sabrina Duarte Alvez — 2024-12-16

This work presents research conducted during the 2023 vintage, aiming to evaluate the response of Arinarnoa, Marselan, and Tannat grape varieties to different red winemaking alternatives. Grapes from each cultivar were characterized, with a particular focus on their phenolic composition, studying the extraction kinetics of these compounds from skins and seeds under controlled and winemaking conditions. The vinifications included traditional maceration and techniques known to modify the polyphenolic composition of wines, such as the use of pectolytic enzymes, the addition of enological tannins, and extended maceration. The wines were analyzed two months after devatting: total polyphenols, anthocyanins, tannins, along with color intensity and color quality. In the harvest considered, Marselan berries had the highest levels of total polyphenols, as well as tannins from both, skins and seeds. Marselan and Tannat had similar Anthocyanin contents, both of which were higher than those in Arinarnoa. The kinetics of seed tannin extraction correlated with the content of these compounds in the grapes, being higher in Marselan, lower in Arinarnoa, and intermediate in Tannat. However, the most remarkable feature of the study was the unusually low skin tannin extraction observed in Marselan, which was much lower than that found in Tannat and particularly Arinarnoa. Thus, during vinification, the addition of pectolytic enzymes resulted in the highest increase in anthocyanins and especially tannins in Marselan, the cultivar with the greatest restriction in extracting these compounds from the skins. In Arinarnoa, the effect of the enzymes was not significant, while in Tannat, it increased anthocyanin extraction, a cultivar characterized by low extractability of these compounds. In the wines, the effect of vinification techniques also depended on the cultivar. In Marselan, all alternatives to traditional maceration increased the total polyphenol content; in Arinarnoa, the effects were not significant, and in Tannat, they decreased. Nonetheless, enzyme addition increased the color of Arinarnoa (8%), being the treatment with the greatest effect on the phenolic composition of Marselan, increasing tannin content (51%), anthocyanins (17%), and color intensity (10%) compared to wines made by traditional maceration. However, the greatest increase in color for this cultivar was observed in wines treated with the addition of skin-derived enological tannins (16%), consistent with the naturally lower content of these compounds typically found in Marselan wines. In Arinarnoa, this treatment reduced color by 5%, and in Tannat, tannin addition had no significant effect on wine color. Extended maceration increased tannin content only in Marselan (45%), while having a negative effect on all measured variables in the other evaluated cultivars. Thus, the interaction of vinification technique with cultivar was evident. Therefore, this study highlights the importance of understanding cultivar characteristics to properly manage the winemaking process.

Respuestas fisiológicas a diferentes ITH en 5 diferentes razas bovinas al norte del Uruguay

Esteban Días Lopez Frola — 2024-12-13

The objective of this work was to evaluate the behavior of the Aberdeen Angus, Hereford, Tulianguy, Brangus and Braford breeds against thermal stress. For this, respiratory rate, rectal temperature, body weight, forehead temperature and flank temperature measurements were taken from 1-year-old calves, three days throughout the summer of 2023-2024 in the town of Morató, Paysandú department, a property belonging to the agricultural engineer and farmer Federico García. A comparison of least squares means was made for the variables respiratory rate, rectal temperature, flank temperature and forehead temperature according to breed and THI. Significant differences were observed for all variables as the THI increased, which was expected according to the consulted bibliography. However, significant differences were only observed between the different genotypes at the same THI for the cases of rectal temperature and forehead temperature, with a tendency towards higher temperatures in these areas of the animal being observed for the British Aberdeen Angus and Hereford breeds, indicating that they are more susceptible to heat stress. In the case of respiratory rate and flank temperature, although there was a tendency towards higher values in the British Aberdeen Angus and Hereford breeds, no significant differences were observed between the different genotypes at the same THI. In average daily gain, although there were no significant differences between genotypes, there were significant differences between the different periods evaluated.

A comparison of least squares means was made for the variables respiratory rate, rectal temperature, flank temperature and forehead temperature according to breed and THI. Significant differences were observed for all variables as the THI increased, which was expected according to the consulted bibliography. However, significant differences were only observed between the different genotypes at the same THI for the cases of rectal temperature and forehead temperature, with a tendency towards higher temperatures in these areas of the animal being observed for the British Aberdeen Angus and Hereford breeds, indicating that they are more susceptible to heat stress. In the case of respiratory rate and flank temperature, although there was a tendency towards higher values in the British Aberdeen Angus and Hereford breeds, no significant differences were observed between the different genotypes at the same THI.

Evaluación y desarrollo de propuestas para mejorar la sostenibilidad del sistema de producción de la familia Bentancur

Diego Fernández Aramburú — 2024-12-13

The current model of intensive production established since the second half of the twentieth century has proved insufficient to ensure the sustainability of productive systems in the medium and long term, putting food security at risk at local, regional and global levels. Organic farming is one of the most sustainable alternatives to counteract the weaknesses of the current model, Focusing on understanding the underlying natural processes of ecosystems and using them in balance with human needs for food production and other products. This work aims to develop proposals for the redesign of the production systems in order to accompany and collaborate towards the agroecological transition of the system under study, focusing on the co-innovation process.

In section 4.1, the system under study was characterized in detail, describing its location, composition, roles and objectives. The production system was then described, and it allowed us to understand the magnitude of the system, its limits, its biophysical and socio-economic characteristics, providing a clear picture of the factors to be considered for subsequent diagnosis.

In section 4.2, the site was evaluated against six defined ecological processes (nutrient cycle, carbon cycle, biotic regulation and plant succession, water cycle, energy flow, socio-economic and cultural) using the MEDITAE framework as an assessment tool, and to establish positive (strengths) and negative (weaknesses) critical points of the system. The system performance was evaluated as good, with the socio-economic, hydrological, biotic regulation and carbon cycle processes being the strengths; and the nutrient and energy cycle ones being the least performing and with greater opportunities for improvement.

In section 4.3, two proposals for redesign were developed and evaluated theoretically, based on three logics: (i) stabilize the cultivated area without loss of production volume; (ii) plan balanced rotations to reduce nutrient imbalances and weed control, and (iii) define and plan the management of semi-natural areas between productive zones.

Chapter 5 discusses the results and evaluation of work carried out at each stage of the process. The discussion focuses on four main themes, (i) contributions of work to agro-ecological improvement of the system, (ii) knowledge gaps and work biases, (iii) the MEDITAE framework as a tool for evaluating socio-ecological processes, and (iv) Contributions towards knowledge building to promote agro-ecological systems in the country.

Evaluación del grano de lupino (Lupinus angustifolius) como suplemento en la recría de terneras ofrecido en comederos de autoconsumo

Carlos Sebastián Isaza Sasias — 2024-12-13

The aim of this research is to assess the effects of lupin grain (Lupinus angustifolium) supplementation and feeding method on the growth and feed conversion efficiency of 36 Hereford heifers grazing on ryegrass (Lolium multiflorum cv Bill max) under restricted forage availability (2.5% of body weight) during winter. The experiment was conducted at the Unidad de Producción Intensiva de Carne (UPIC) located at the Estación Experimental Dr. Mario A. Cassinoni (EEMAC), Facultad de Agronomía, Paysandú, Uruguay. The heifers were assigned to three treatments in a randomized complete block design (three grazing parcels per treatment, four heifers per parcel): grazing without supplementation (control), daily supplementation at 1% of body weight, and ad libitum self-feeding supplementation. Supplementation improved weight gain (1.21 kg vs. 0.74 kg; P<0.01), and among the supplemented groups, weight gain was higher in the self-feeding treatment (1.3 kg vs. 1.13 kg; P<0.01), associated with a higher supplement intake compared to the daily feeding method (3.9 kg DM/head/day vs. 2.10 kg DM/head/day; P<0.01). Feed conversion efficiency of the supplement showed no significant differences between treatments (SD: 5,73 y AC: 6,85, P>0.05). The higher supplement intake in the self-feeding treatment resulted in a higher meat production (kg/ha). These findings suggest that including lupin grain through different feeding methods may be a viable option for commercial operations.

Interacción déficit hídrico-ambiente lumínico en la respuesta fotosintética de plantas de soja (Glycine max (L.) Merril)

Noelia Carolina Torres Corbo — 2024-12-13

Soybean is the main agricultural crop in Uruguay. Its yield varies depending on water conditions during growth, the availability of soil nutrients, as well as the light environment for growth. The objective of the study was to analyze the photosynthetic activity response in soybean (Glycine max) leaves to changes in light environments with different spectral compositions (white light, white light enriched in red, blue light, and red light) and water conditions (control and Deficit). Two genotypes (Don Mario 6.8i and Génesis 5601) were used, and four replicates were performed per treatment. The treatments were defined by the interaction of the genotype factor (Don Mario 6.8i and G5601), the water condition factor (control and Deficit), the light environment factor (White1, White2, Blue, and Red), and a level of actinic light factor (850 μmol photons m⁻² s⁻¹). Energy partitioning in PSII was studied based on three main parameters (Φ_PSII, Φ_NPQ, and Φ_NO) and two sub-parameters (Φ_NPQ._fast and Φ_NPQ.slow). Additionally, variance analyses were conducted to determine whether there was a significant effect of the factors on the studied parameters, and a contrast analysis was performed to establish differences between the treatment means. It was evident that the light environment during the development of a soybean plant determines PSII efficiency, as well as that the spectral quality of the development light environment determines the energy partitioning strategy in a functional soybean leaf. It was also found that the combination of water deficit and spectral deficiency reduces the efficiency of the photochemical phase of the photosynthetic process.

Evaluación y desarrollo de propuestas para mejorar la sostenibilidad del sistema de producción de la familia Bazzano – Gallo

Santiago Irurueta Cabrera — 2024-12-13

This work sought to systematize the productive experience of José Luis Bazzano and Brenda Gallo, and to generate proposals that contribute to improve the productive system, using the co-innovation methodology. In the first stage, a characterization and sustainability diagnosis of the current farm system was carried out, and then a farm redesign proposal was developed to overcome the limitations found during the diagnosis phase in order to contribute to the consolidation of the agroecological system. During the farm work, the MEDITAE framework (Marco de Evaluación y Diagnóstico para Impulsar Transiciones AgroEcológicas) was developed and used as a tool to support the farm co-innovation process, deepening the agroecological approach in the analysis. In this sense, the work also provides methodological elements for the study and development of agroecologically based systems. It was identified that the main problems of the farm were related to the ecological processes of carbon and nutrient cycling (loss of organic matter and soil nutrient stock), energy flow (low annual soil cover and low crop yields), and some aspects linked to the socio-economic process (fundamentally linked to family income and dependence on few and fluctuating commercial channels). The main objective of the proposal was to reduce the pressure on family labor by ordering and prioritizing activities, and to increase or in some cases maintain the total harvested volume by reducing the horticultural area. It also sought to raise awareness of some key management points that were not being fully contemplated by producers, for example, the negative balance of carbon and nutrients in the soil, which strongly questioned the sustainability of the system. At the same time, the proposal generated allows a larger area to be set aside for spontaneous and/or semi-permanent cultivated vegetation, promoting biodiversity conservation and encouraging the use of irrigation to stabilize the quality of production and ensure productive processes. In spite of some weaknesses identified in the MEDITAE framework, typical of a development process, it was understood that it provides a global vision of the systems, focusing on the understanding and analysis of the socio-ecological processes and their interactions, enriching the discussion and deepening the agroecological approach, with an enormous potential contribution as a tool for research, teaching and extension.

Caracterización química y análisis de la variación axial y radial de la anatomía y densidad de la madera de Eucalyptus grandis W. Hill ex Maiden

Eugenia Campón Viña — 2024-12-13

The Eucalyptus genus, recognized worldwide for its rapid growth and adaptability, is predominant in Uruguay, where it accounts for 72% of all plantations. Among its species, Eucalyptus grandis stands out for its advantages in the national context and it is expected to continue expanding due to its ability to thrive in diverse conditions and its stability in the face of climate change. Consequently, studying its anatomical, chemical, and physical properties is essential; this knowledge not only deepens the understanding of the species' characteristics but also aids in identifying potential uses and promotes more efficient utilization, thereby maximizing its added value.

This study, conducted in the Cerro Largo department of Uruguay, aimed to compare the anatomy and basic apparent density of healthy wood from 30-year-old Eucalyptus grandis trees at different radial positions and trunk heights, as well as to characterize their chemical composition and dendrometric features. The specific objectives included: performing dendrometric characterization of the studied trees, comparing the anatomy of healthy wood across the radius and at different trunk heights, characterizing its chemical composition using descriptive statistics and evaluating variations in basic apparent density radially and with trunk height.

In a stand at the Estación Experimental Prof. Bernardo Rosengurtt (EEBR) of the Faculty of Agronomy, five healthy trees with similar diameters and no cracks were randomly selected. Various heights (stump, first branch, and total) were measured, along with diameter measurements taken every meter until reaching 8 cm at the thin end. Discs were collected from each tree at heights of 0.5 m, 1 m, and 1.5 m, resulting in a total of 15 samples. In the laboratory, four samples per disc were extracted, and each was then sectioned into four subsamples from pith to bark, identified according to their radial location and methodological use: anatomy, chemistry, or density.

Dendrometrically, the trees averaged 25.84 m in total height, 9.41 m to the first branch, and 0.21 m in stump height. The average diameter at breasy height - DBH was 25.96 cm, showing a progressive decrease in diameter with increasing height. In terms of anatomy, fibers had an averaged length of 986.310 µm, a diameter of 21.100 µm, and a cell wall thickness of 3.484 µm, with significant differences based on radial position -these increased from pith to bark- without significant variations based on height or interaction between height and radial position. Chemically, the averages obtained were: 7.571% moisture content, 6.255% extractives, 2.044% soluble lignin, 28.317% insoluble lignin, 73.293% holocellulose, and 0.310% ash. The average basic apparent density was measured at 0.413 g/cm³, decreasing with height while increasing radially from pith to bark, without significant interaction between height and radial position.

Sustitución parcial del grano de maíz por grano de arroz con cascara en raciones de engorde de vacuno

Marcela Paolino Porcile — 2024-12-12

The objective of this study was to evaluate the effect of partial substitution of corn grain by Paddy rice or whole ricein fattening rations for steers, and the effect of processing of UNP (cracked vs ground) and moisture level (vs) on carcass and meat quality. Traditionally, corn grain is the main ingredient in intensive fattening diets due to its high energy value and digestibility. UNP was proposed as a potentially viable alternative, especially in adverse market situations or unfavorable weather conditions for the rice industry.

The study was carried out at the Intensive Meat Production Unit (UPIC) of the Mario A. Cassinoni Experimental Station (EEMAC) in the city of Paysandú, Uruguay. The experiment was conducted under confined conditions. The 48 steers were assigned in a randomized block design to one of four experimental diets: Hereford steers fed diets that differed in grain type (corn or GACC), degree of processing of the GACC (cracked or ground) and moisture level (dry or wet). Offered ad libitum for 89 days. The animals were slaughtered on a fixed date at the Casa Blanca slaughterhouse in the Paysandú department. The results showed that, although GACC has a different chemical composition than corn (specifically in terms of fiber content and energy content), the substitution of the latter for GACC did not significantly affect characteristics related to meat quality, such as tenderness, marbling, pH, muscle color, backfat thickness and ribeye area, as well as carcass quality variables such as carcass weight and yield.

The inclusion of GACC is proposed as an alternative to partially replace corn in feedlot fattening diets for steers, without negatively affecting carcass and meat characteristics, which opens an opportunity to integrate rice production with livestock.

Evaluación productiva de la gestión del pasto, efecto del método de pastoreo y la oferta de forraje a campo natural

Marcelo Ezequiel Hernández Bernaschina — 2024-12-09

Understanding the influence of soil conditions, forage supply and grazing method on primary and secondary production, as well as on the quality of the natural cover is essential to develop prosperous and sustainable production systems. A 2x2 factorial structure experiment is being carried out on paddock 13 of the Mario Alberto Cassinoni Experimental Station (La -32.387511°S and Lo -58.033235°W), where two forage supply levels (low and high, 8% and 12%, respectively) and two grazing methods (rotation and continuous) are being evaluated. The work was done with Holstein steers. The supply was adjusted by monthly sampling that allowed the estimation of available dry matter (kg/ha), based on which changes of animals were made, destined to adjust the load, between pastures. These animals were also weighed monthly. The evaluation period covered from November 1, 2023 to April 25, 2024, so the end of spring, the entire summer, and the beginning of autumn were evaluated. Within this period, subperiods were constructed in such a way that the variability of the factors was evaluated monthly. The work was carried out with the objective of determining the botanical composition of the natural field in relation to the different treatments, as well as the primary and secondary production of the field. In order to take into account the edaphic influence, the pasture was divided into low, medium and lithosol zones, using cartographic bases and visual estimation. The variables determined were dry matter production (kg DM/ha), growth rate (kg/day/ha), dry matter availability (kg DM/ha), forage height (cm), forage use (% of available), botanical composition of the mat, daily gain of animals (kg LW/animal/day), live weight gain for the period per animal (kg LW/animal) and per hectare (kg LW/ha). Using the statistical program InfoStat, a qualitative analysis of the botanical composition was performed, allowing the construction of dendrograms, and a quantitative analysis of all variables was performed using the analysis of variance (ANAVA), subsequently performing a Tukey comparison with a 10% significance level. The results show that pasture height is strongly influenced by forage supply and method, with high rotation being the one that allowed the highest heights, with a strong influence of soil conditions, with the highest heights being in the low pasture and the lowest in the lithosols. Botanical composition was strongly influenced by soil conditions, with contrasting communities found between the different areas, with the influence of forage supply and method on the heterogeneity formed. Utilization was determined by forage supply, with a higher level of utilization under low supply. Area and forage supply were highly influential on growth rate, with a higher level of utilization under low forage supply areas. Animal productivity was not determined by the different management variables evaluated.

Efecto de la fertilización nitrógeno-fosfatada y de la incorporación de leguminosas en campo natural sobre la composición botánica y la producción primaria y secundaria

Francisco Emilio Fernández Rariz — 2024-12-09

This study was conducted in paddock 18 of the Mario A. Cassinoni Experimental Station at the Faculty of Agronomy, located in the Paysandú department, Uruguay (-32º39’96’’ S, -58º04’45’’ W). The experiment, established in 2014, has undergone management monitoring, including grazing practices and the addition of inputs, as well as a potential residual effect from these inputs. The evaluation period spanned from April 2, 2024, to July 22, 2024, encompassing 111 days divided into two complete grazing cycles: Cycle 1 (April 2, 2024, to May 27, 2024) and Cycle 2 (May 27, 2024, to July 22, 2024). The objective of the study was to assess two intervention technologies in natural pasture: nitrogen-phosphorus fertilization and the introduction of Lotus tenuis and Trifolium pratense along with phosphorus application. The effects measured included dry matter (DM) production, botanical composition, and secondary production. The treatments were as follows: control without intervention (NP), improved natural pasture with legumes and the addition of 40 kg P2O5/ha (INP), and two levels of nitrogen fertilization: 60 kg/ha/year (N60) and 120 kg/ha/year (N120), split equally between autumn and winter, along with the addition of 40 kg P2O5/ha. These treatments were arranged in a completely randomized design with four replications. For each variable considered, an analysis of variance and orthogonal contrasts were performed. These variables included the height of available dry matter (DM), available DM, percentage of available green matter (GM), height of residual DM, residual DM, percentage of residual GM, percentage disappeared, accumulated production, and growth rate. Additionally, seventeen botanical groups, percentage of bare soil, percentage of weedy cover (WC), average daily gain (ADG), and percentage of forage supply (FS) were analyzed. The study indicates that no superiority in forage production was observed with increasing levels of intervention, primarily due to unfavorable climatic conditions. Similarly, the addition of inputs resulted in changes in the composition of the sward, favoring high-quality forage species, particularly concerning Lolium multiflorum. This resulted in increases in the ADG of the studied animals, showing significant differences between the CN and N120 treatments, while the other two exhibited intermediate behavior. It is important to highlight that the increase in meat production occurs at the expense of the replacement of perennial species by annuals, which could pose an ecological threat.

Comportamiento de novillos Wagyu puros en confinamiento

Francesco Compa Duffey — 2024-12-06

The purpose of this experiment was to evaluate the ingestive behavior of 32 Wagyu breed steers in the "El Oriental" cabin in Mercedes. The objective of this study is to be able to analyze if there is a difference in their behavior (Number of views to the feeder, Effective minutes in the feeder and Daily intake weight) of them when providing them with different diets. The study divided the 32 steers into 3 different treatments plus a repetition, each treatment had 8 steers and they were fed a diet with different characteristics between treatments 1, 3 and 4; treatment 1 and 2 were repetitions. The diets were differentiated into wet and dry, also including the addition of lipids. To analyze the results, analysis of variance and Tukey tests were applied using the MIXED and GLM procedures in the SAS program for statistical analysis, where we evaluated differences between treatments and then the individual performance of each steer within each treatment. Comparing the results we could observe that there are significant differences between treatments as well as between animals of the same treatment. The results obtained from this work are that depending on the type of diet given to the animal, its behavior varies. It was observed that there were statistically significant differences in effective minutes in the feeder and ingestion weight of the animals according to the diet provided. In conclusion, it can be said that depending on the diet that is provided to the animal, it will behave differently with different diets.

Evaluación del grano de arroz con cáscara (GACC) como suplemento ofrecido en autoconsumo a vacunos pastoreando raigrás

Marina Coduri Pacheco — 2024-12-06

The present study was conducted in paddock number 2 of the Intensive Beef Production Unit (UPIC) located at the “Dr. Mario Alberto Cassinoni” Experimental Station (EEMAC), Faculty of Agronomy, Paysandú, Uruguay. The objective was to evaluate the effect of supplementation with broken rice grain with husk (GACC) and its feeding method (daily at 1% of live weight or ad libitum self-feeding) on the degradation kinetics of the supplement and forage, ruminal fermentation parameters, and behaviour of steers grazing ryegrass during the autumn-winter period. Three Hereford steers, fistulated and born in the spring of 2022, from the experimental station's own herd were used. The steers had an average weight of 282.3 ± 18.9 kg at the beginning of the experiment. Animals were randomly assigned to each treatment using a Latin square design over three periods. The treatments applied were as follows: exclusive grazing of Jack cultivar ryegrass with forage allocation of 2.5% of live weight (LW) without supplementation, daily supplementation at 1% of LW with GACC, and ad libitum supplementation with GACC. Grazing was conducted in strips with weekly shifts, and supplementation was provided individually once a day in the morning. The variables evaluated for each treatment included dry matter (DM) intake, in situ degradability, in vivo digestibility of DM, ruminal pH and ammonia, and behaviour. No significant differences were observed among treatments in DM intake of GACC, forage, or total diet. Similarly, no differences were found in ruminal pH or ammonia levels. No significant differences were detected among treatments in organic matter and DM digestibility. However, differences were observed in the in situ degradability of DM of the feeds between the self-feeding and daily supplementation treatments. There is limited global research on the ruminal kinetics of GACC in livestock supplementation, which highlights the significance of this experiment in the field of animal nutrition.

Evaluación del grano de arroz con cáscara (GACC) como suplemento en la recría de terneros ofrecido en comederos de autoconsumo

Inés Giudice Silveira — 2024-12-05

The primary objective of this study was to evaluate the effect of supplementation with unprocessed rice grain (GACC) offered in a self-feeding system on the growth and feed efficiency of calves grazing on winter forage crops. This experiment was conducted at the Intensive Meat Production Unit (UPIC) at the Mario A. Casinoni Experimental Station (EEMAC) in Paysandú, Uruguay, from July 6 to September 28, 2023.

A total of 36 nine-month-old Hereford calves born in the spring of 2022, with an average initial weight of 162 ± 13.5 kg, were used. The animals were divided into three treatments, each with three replicates, forming nine groups of four animals each. The three treatments were: control (no supplementation), daily supplementation at 1% of body weight (BW), and ad libitum feeding with a self-feeder. For all treatments, the base diet consisted of Lolium multiflorum cv Jack with an allocation of 2.5% of BW.

Supplementation with GACC affected the average daily gain (ADG) in the supplemented treatments compared to the control. Moreover, there was a significant difference in ADG and feed efficiency (FE) between the supplemented groups.

The control animals achieved an average gain of 0.638 kg/day, those receiving GACC daily at 1% BW gained 0.917 kg/day, and the ad libitum supplemented animals gained 1.25 kg/day. The feed conversion efficiency of the supplement for the latter two treatments was 8.23:1 and 5.57:1, respectively.

It was concluded that there is a response to GACC supplementation and that it is feasible to provide it in self-feeding troughs.

Efecto residual de distintos cultivos de servicio sobre el enmalezamiento invernal

Agustina Soledad Azcoitía Aramburo — 2024-12-04

In 2023 an experiment was conducted in the Experimental Station “Dr. Mario A. Cassinoni” (E.E.M.A.C) of the Faculty of Agronomy in Paysandú (Uruguay) in order to evaluate the residual effects of different cover crops (CC) on winter weed infestation the following year. The experimental design was a randomized complete block design (RCBD) with 3 replications. The treatments evaluated were Persian clover (Trifolium resupinatum), hairy vetch (Vicia villosa), black oats (Avena strigosa), a mixture of black oats and hairy vetch, yellow oats (Avena byzantina) and a control without plant cover During the fall and winter of 2023, the weeding was evaluated in three stages: fallow prior to barley sowing, crop establishment and pre-harvest. The assessment included identifying and quantifying present weed species, their phenological stage, total weed coverage, residue cover from the previous crop, bare soil coverage, and barley crop coverage. To complement the analysis, data collected at the end of the CCs cycle in 2022 was used. The results were analyzed with ANOVA using the statistical software InfoStat, applying Tukey's test at a 5% significance level for mean separation. The CCs that at the end of the cycle achieved greater and faster soil cover —black oats, hairy vetch, black oat-hairy vetch mixture and yellow oats— showed fewer weeds in the reproductive stage. This effect continued until fallow period, prior to barley planting, except for hairy vetch, resulting in less weeding. Black oats and the black oat-hairy vetch mixture maintained their suppressive effect at planting, while Persian clover was the least effective, performing even worse than the control. In barley preharvest, 100% cover was achieved, with no significant differences in the total or spectrum of weeding. These results demonstrate that the residual effects of CCs on winter weeding the following year varied according to the CC and weeds present in the field, being more evident during the fallow period prior to barley sowing than during the crop cycle.

Caracterización anatómica de la madera de híbridos de Eucalyptus grandis y Eucalyptus dunnii y evaluación de su potencial para la producción de celulosa y papel

Vera Torres Ibáñez — 2024-11-28

Uruguay has been the scene of various investigations with Eucalyptus hybrids. In this case, hybrids between Eucalyptus dunnii and Eucalyptus grandis were studied in order to combine the most desirable characteristics of both species. The general objective of this work was to biometrically characterize the cellulose fibers of 201, 3-year-old trees of the mentioned hybrids, measuring the length and width of the cellulose fiber to obtain the slenderness index as a quality indicator. A maceration was done out to visualize and measure a total of 25 fibers from each tree using an optical microscope. To complement the measured data, UPM provided the diameter at breast high, height, volume, basic density and pulp yield for each tree. The observed fibers were libriform, presenting an average fiber length of 808,0 μm and an average fiber width of 13,63 μm. For fiber length and width hybrids presented significant differences, with E. dunnii x E. grandis being the one with the longest and thinnest fibers, presenting an average of 814,2 μm long and 13,34 μm wide. While E. grandis x E. dunnii presented shorter and wider fibers with averages of 795,2 μm long and 14,25 μm wide. The average slenderness index was 59,87% and like the length and width, it presented significant differences between hybrids with E. dunnii x E. grandis being the one with highest average slenderness of 61,55%, while that of E. grandis x E. dunnii was 56,33%. As well as the anatomical characteristics, volume, basic density and pulp yield also showed significant differences between hybrids, with E. dunnii x E. grandis showing differences the highest averages in the three variables mentioned. Likewise, the correlation between volume, basic density, pulp yield and slenderness were analyzed and all the correlations were positive and significant. When analyzing the importance of the variables on pulp yield, it was found that the one with the greatest influence is basic density, followed by volume and finally slenderness, with importance values of 57,80%, 57,66% and 50,94% respectively. This was represented in a regression tree, where a total of 37 individuals are in the group with the highest pulp yield. Regarding the comparison between the 29 families analyzed, we obtained two different clusters. These are mostly grouped by crossing, that is, on the one hand, those E. dunnii x E. grandis families and on the other hand, those E. grandis x E. dunnii. All the results obtained were used to generate a database useful for genomic selection.

Fungicidas usados en cereales de invierno y su potencial riesgo en el ambiente

Agustina María Machado Diaz — 2024-11-22

Winter cereals in Uruguay, particularly wheat and barley, are highly important crops. Their yield and quality can be affected by diseases, with the primary management strategy being the use of foliar fungicides. However, these fungicides may have unintended impacts on non-target organisms and environmental compartments. The objective of this study was to identify the potential environmental risks associated with fungicide applications in Uruguay for disease control in wheat and barley. The specific goals were to assess exposure, hazard, and environmental risk at a national level and estimate these risks in four farms located in the country's main winter cereal-producing region. To evaluate the potential risk, active ingredients were selected based on data from INIA and the DGSA. Their physicochemical properties were analyzed to characterize exposure. The hazard was assessed by examining toxicity in species from soil, water, and air compartments, using data provided by the Pesticide Properties Database from the Agriculture & Environment Research Unit. In the selected farms, Toxic Units (TU) were calculated for terrestrial, aquatic, and aerial organisms during the 2021/2022, 2022/2023, and 2023/2024 seasons, identifying which scenario presented the highest potential risk. Of the active ingredients studied, 14% showed a high probability of persisting in the soil compartment, influenced by their composition. These conditions, combined with predisposing climatic factors, determine the environmental impact by affecting fungicide degradation and transfer to other compartments. As a result, 39% could be found in both soil and/or aquatic environments, while 14% were specifically identified in the aquatic compartment. The remaining 32% were likely to degrade in either environment. Regarding hazard characterization, the potential toxicological effects on mammals, earthworms, birds, bees, fish, invertebrates, and algae were determined. In terms of the farm study, the one that planted wheat and barley across all seasons, with the highest number of applications and doses, exhibited the greatest potential risk to all studied organisms. This study enabled the characterization of the hazard and environmental fate of fungicides used for disease control in winter cereals in Uruguay. The results highlight the need to intensify efforts to thoroughly characterize exposure, allowing for better risk estimation and the adoption of sustainable practices and/or mitigation measures.

Identificación y evaluación de discrepancias entre los mapas de ambiente a partir de mapas de rendimiento

Agustín Arrospide Blengio — 2024-11-21

Precision agriculture uses various tools to optimize agricultural production, including environment maps for the differential application of inputs. However, maps generated from vegetative indices do not always adequately reflect areas of higher or lower yield, which can reduce the efficiency of input use. The objective of this final degree project is to identify and evaluate the discrepancies between environment maps generated using vegetative indices (NDVI, GNDVI) and corn and soybean yield maps. We worked with nine lots distributed in three areas of the provinces of Santa Fe and Buenos Aires, using yield maps from three consecutive harvests (27 maps in total) and environment maps provided by the MSU Agro company. The methodology included the development of a model in QGIS to filter outliers in the performance maps and compare them with the settings. Annual and average evaluations were carried out to analyze discrepancies between the maps. In addition to this, the kappa coefficient was calculated for each situation, and a principal component analysis (PCA) was performed in R to investigate possible relationships between the discrepancies and variables such as organic matter, nitrogen, and rainfall during the critical period. The results indicated that, on average, 52% of the points coincided with the expected performance, while 48% presented discrepancies, being more significant in low productivity environments. These areas showed greater interannual variability, possibly due to adverse climatic conditions. Furthermore, the kappa coefficient suggested that the use of several performance maps when setting, improves the precision of the settings, since they reduce the year effect. The PCAs revealed that the discrepancies could be influenced by soil variability and climatic factors. In conclusion, creating environment maps based on years with average climatic conditions is an effective strategy to reduce long-term discrepancies, although it is also important to consider soil variability to improve results.

Apertura mandibular y acarreo de cebos en hormigas cortadoras del género Acromyrmex sp.

Florencia Mariana Olveira Gordillo — 2024-11-14

Leaf-cutter ants are the main forest pest in the region, causing economic losses in both Eucalyptus and Pinus plantations.

The most efficient way to control them so far is the application of chemical baits, which are transported to the nest. This is why the success of such control depends on the ants lifting the bait.

Under the hypothesis that not all species of Acromyrmex can lift the currently used commercial baits with the same efficiency, we proceeded to evaluate the effect of mandibular opening on the ability of Acromymrex workers to forage on ant baits. For this purpose, two species of Acromyrmex present in the study area with different mandibular openings were compared: Acromyrmex lundii and Acromyrmex heyeri.

Colonies of both species were located at the Facultad de Agronomía in autumn 2022 and were offered Lampo (AI: fipronil) and Dinagro (AI: sulfluramid) baits. Ants collecting the bait were measured for the time taken to recognise the bait, accept it and lift it to the path, head size, mandibular opening and weight of the worker, as well as the length of the lifted pellet.

The results obtained in this study indicate that among the workers that did not carry bait, A. lundii has a greater jaw opening capacity than A. heyeri, however, with regard to head size, A. heyeri is the one with the largest head size, with the majority being between 2.0 mm and 3.0 mm, while for A. lundii it ranges between 1.5 mm and 2 mm. As for the time taken by the ants to lift the bait, only 17% was explained by the variables studied: head width, ant weight and bait length. There are significant differences between the length of the bait and the time it takes to lift the bait for both species. In turn, it is observed that A. lundii workers take longer to travel the 40 cm than A. heyeri workers. Of the two explanatory variables, the one that had the greatest significance and explained the greatest percentage of the variation in the time taken to travel 40 cm was the ant's weight. A. heyeri appears unaffected by bait length or the weight of the ant during transport, allowing it to move faster.

A. lundii achieves larger mandibular openings than A. heyeri and as the commercial baits that exist to date for the control of leaf cutter ants are up to 2 mm, both A. heyeri and A. lundii are capable of lifting the bait because of their mandibular opening capacity, so the failures in the control would not be explained by this physical factor.

Evaluación comparativa de cultivares de cebolla en tres fechas de siembra y trasplante

Charlie Emanuel de los Santos Texeira — 2024-11-11

Given the market and the constant needs of farmers to not only offer better quality vegetables, but also adapt them to their production systems or geography, continuous research and development of new and diverse materials has been required to ask these demands. Within the afore mentioned vegetables, those that are most consumed, such as onions, have been most studied and developed, in which we can find in the market a great diversity of plant materials, both national and foreign, but based on this diversity a series have emerged. of questions such as: do we know the behavior of each variety in Uruguay? Does any variety adapt to my production area and objectives? What are the factors that play a fundamental role if I want to achieve good returns? Does it affect the dates I plant or transplant this crop? How are the resistance of different plant materials to diseases and pests?

This work arises from the need to know how the behavior of various onion materials used in the country is compared to different management in terms of the date of sowing and transplanting, and what factors determine the success of a good harvest, in addition to know what the physiological and organoleptic characteristics of the evaluated varieties are like. In this way, we sought to provide a certain answer to some of the aforementioned questions.

In order to find an answer in this thesis work, 13 varieties of onion were used, divided into three trials depending on the type of material cycle (DC, DI or DL). The trials started from three different sowing dates and therefore also transplanting. Throughout the growth period, different parameters were measured on successive occasions to generate sufficient information and from which to compare the growth evolution between the varieties, physiological states, quality and harvest time. Post-harvest measurements of different physiological attributes that determine commercial quality were also carried out. The variability of these attributes is necessary to know given the different objectives of the producers.

Efecto de la composición del paisaje sobre la abundancia de artrópodos predadores e insectos plaga en el cultivo de soja

Ana Paula Jauregui Hernández — 2024-10-31

In Uruguay, soybean [Glycine max (L.) Merril] is currently the predominant summer crop in agricultural-pastoral landscapes. The area planted with soybeans in the country has been evolving increasingly over the last 20 years together with a process of agricultural intensification. This phenomenon caused the loss of landscape heterogeneity due to the increase in area of annual crops and the removal of semi-natural habitats. The agricultural expansion occurred to the detriment of sites of permanent vegetation, such as the natural fields, which act as refuge sites for natural controllers, determining a possible increase in pest pressure and the use of insecticides. In the present work, we evaluated the effect of landscape composition on the abundance of predatory arthropods and pest insects in soybean fields. The hypothesis was the following: predominance of agriculture in the landscape negatively affects predators and increases the abundance of pest insects in soybean fields. It was concluded that the floristic composition of the surrounding landscape (1km) differentially affects the abundance of the main groups of predatory arthropods. Most simple landscapes with a predominance of agriculture (greater than 50%) have a lower abundance of total predators and the natural field was positively associated with spiders and predatory hemipterans. The results obtained show that the landscape composition is important in predator arthropod population dynamics and certain pest insects. Therefore, when the man intervenes in said landscape, this also has an impact on this important link in the food chain.

Composición y calidad nutritiva de una pastura con base en festuca pastoreada por vacas lecheras, con distintas alturas remanentes en primavera

Daniel Castromán Alzueta — 2024-10-23

The effect of the remaining height (AR) of a fescue on the nutritional and botanical composition of the pasture was studied. The objective was to test higher heights than those currently recommended and observe their impact on the aforementioned variables. The criterion for entering grazing was when the fescue reached the physiological state of three leaves. During spring, two remaining heights were compared: control treatment (TC; 9 cm) and lax treatment (TL; 15 cm). Twenty-four multiparous Holstein cows calved in autumn, with 3.2 ± 0.82 lactations, 580 ± 41.3 kg LW and 2.5 ± 0.16 units of BCW at calving were blocked by the number of lactations, LW, calving date and CC. It was managed with rotational grazing, where each grazing lasted an average of 7.5 and 5 days, for TC and TL; respectively. During the experiment in the spring, TC animals tended to increase their grazing time, with longer duration sessions compared to TL. The TL animals showed more stable behavior throughout the grazing days, and managed to harvest higher quality forage. The results show that there is a response in nutritional quality to RA that is laxer than those recommended at the national level. Higher AR allowed the animals to graze better quality forage, in less time and with greater use of nutrients.

Efecto del manejo del pastoreo en el comportamiento y en la performance productiva de vacas lecheras de alta producción en un sistema mixto de alimentación

María Victoria Pereira Bernasconi — 2024-10-22

A study was conducted to evaluate the effect of two contrasting defoliation intensities on a second-year Festuca arundinacea pasture on the behavior, forage and total dry matter intake, and milk production of dairy cows. Two post-grazing heights were applied: 12-15 cm (treatment TL) and 5-7 cm (treatment TT). Grazing was initiated when the pasture reached 18-20 cm in height and/or three leaves per tiller. Thirty-two autumn-calving Holstein cows were used, grouped based on calving date (3/4/2023 ± 14,5 days), previous milk yield, body weight (665 ± 12,9 kg), body condition score (BCS; 3,3 ± 0,04), and number of lactations, and randomly assigned to the treatments. After the morning milking, the cows had access to the pasture, and after the evening milking, they were housed in a compost barn until the next milking. Grazing and rumination times, as well as the number and duration of grazing sessions, were recorded automatically. Forage intake were estimated through energy balance, and milk production was measured daily. Response variables were analyzed using PROC GLIMMIX in SAS. Grazing time was not affected by treatment (298 ± 8,6 minutes). The reduction in post-grazing height increased the duration of the first grazing session (174 vs. 139 ± 8,5 minutes). The number of grazing sessions was higher in TL at the midpoint of the occupation period, while TT did not alter the number of sessions during the occupation period. Forage intake was higher in TL (12,0 vs. 9,1 kg DM/cow/day), which explained the higher dry matter intake (25,6 vs. 22,4 kg DM/cow/day). Milk production during the general evaluation period and the specific measurement period was higher in TL than TT (38,9 vs. 36,2 ± 0,54 and 37,3 vs. 33,2 ± 1,02 kg/cow/day). Fat and total solids concentrations did not differ between treatments, while protein and lactose concentrations showed a significant treatment by month interaction. The BCS at the end of the experiment was higher in TL than in TT (3,3 vs. 3,1). TL achieved higher milk production and BCS, which was explained by higher pasture intake through changes in ingestive behavior.

Análisis del arbolado de alineación del Municipio A en base al sistema único de respuesta de la Intendencia de Montevideo

Elisa Grubits Reyes — 2024-10-17

Urban trees provide environmental, social and/or economic, aesthetic and urban physiognomy benefits, but they also generate a series of problems as a result of their interaction with the infrastructure, the population, and the environment in which they are developed. The Municipal Governments have the task of maintaining the trees aligned in paths of their territorial jurisdiction. The “problems” caused by trees or perceived by citizens that they could cause, are managed through the Single Response System of the Municipality of Montevideo (SUR), where through technical reports the actions to be taken for their resolution are defined, trying to facilitate and increase the response capacity towards the population. The problems are categorized and relate to requests for aerial pruning treatments, trees in poor vegetative condition or that interfere with garage entrances, situations of root interference on sidewalks or buildings, fallen trees or branches after a storm and plantations. Analysing the problems of the trees based on the requests of the citizens of Municipality A submitted to the SUR and relating them to the population, urban and tree situation of each Zonal Community Centre, made it possible to evaluate the most frequent types of problems in each territory. The urban tree census, the evaluation of the municipality's trees as well as the management treatments carried out in the population, made it possible to identify guidelines to improve municipal management. Within these guidelines, the development of a Tree Management Plan is suggested as a tool to effectively meet the objective of maintaining the existing trees on trails; the need to update the tree census; promote permanent education of both the personnel who manage the trees, as well as the citizens in good forestry practices but also, educate on the possible future problems that trees can cause in the urban environment to achieve success in planning. On the other hand, contribute to a change of perspective in terms of how citizens perceive trees in the city, balancing the benefits against the disadvantages with the objective of promoting an environmentally sustainable, efficient and safe Municipality.

Análisis de factores que determinan la variación en rendimiento de cultivos de cáñamo en el sur de Uruguay

Imanol Arismendes Sastre — 2024-10-14

The cultivation of Cannabis sp. has gained relevance in Uruguay following its decriminalization in 2014. This research aims to analyze the factors that determine yield variability in hemp crops in the southern region of the country during the 2021-22 and 2022-23 seasons. The study focuses on characterizing production systems oriented towards flower production with high CBD content and identifying the main factors influencing crop yield. To achieve this, the regional agronomic diagnostic methodology was applied. A sample of 21 companies was selected for the 2021-22 season, with 31 open-field crops and 10 greenhouse crops. For the 2022-23 season, 10 companies were included, with 12 open-field crops and 10 greenhouse crops. Information on the production system and available resources was collected on each farm. Additionally, for each crop, data on yield and determining, limiting, and reducing factors were recorded.

The results revealed significant variability in yields among different crops. The primary factors explaining this variability were individual plant yield, planting density, and radiation interception at the beginning of harvest. Higher planting density and higher foliar nutrient content were positively associated with yield. Furthermore, the sodium content in irrigation water and shoots showed a significant negative impact on yield.

This study is of great relevance given the limited scientific information available on hemp cultivation following its legalization, highlighting the need for further research to optimize production and improve hemp quality in the region.

Aporte de nitrógeno al maíz por parte de distintos cultivos de servicio invernales tales como gramíneas puras, leguminosas y sus mezclas

Federico Bentancor Salvo — 2024-10-10

From the late 20th century until the full implementation of the Responsible Land Use and Management Plans (PUMS for its Spanish acronym) in 2013, cropping systems underwent a series of changes that led to an increase in the frequency of continuous cropping sequences, based on obtaining one crop per year, which established a highly extractive system. These changes were reflected in the presence of long periods of winter fallow between the planting of summer crops, leading to the deterioration of the soil's physicochemical properties by favoring processes such as water erosion, nutrient loss due to leaching, and soil compaction, among others. The implementation of the PUMS, which sets erosion tolerance limits for soils, established the need to keep the soil covered. This was translated commercially into a significant increase in winter agricultural area based on the incorporation of cover crops (CC). In addition to keeping the soil covered, these crops can also contribute carbon to the system and recycle nutrients, among many other ecosystem services. The objective of this work was to evaluate the effect of keeping the soil covered with 6 winter CCs on gravimetric moisture, soil N-NO-3, and their impact on the subsequent corn crop. For this purpose, two pure grasses (Avena strigosa and Avena byzantina), two mixtures of grasses with legumes (Avena strigosa + Vicia villosa and Avena byzantina + Vicia villosa), two pure legumes (Vicia villosa and Lupinus angustifolius), and finally fallow as a control were used. Additionally, the effect of nitrogen fertilization on the corn crop was addressed by fertilizing subplots within the treatments with the following doses: 0 kg N ha-1, 40 kg N ha-1, and 80 kg N ha-1 at different stages of the crop. For this particular experiment, conducted at the EEMAC in the city of Paysandú, differences were found in variables such as establishment, soil N-NO-3, and stubble N. It is worth noting that the rainfall was not representative of the region's water regime, being well below the average.

Caracterización de la calidad de semilla de soja de uso propio zafra 2018-2019

Viviana Plavan Rohrer — 2024-10-08

The production of soybeans (Glycine max (L.) Merr.) in Uruguay is an important sector of the economy, leading agricultural development over the past two decades. In Uruguay, both national and imported seeds are used, and the use of certified seeds is encouraged to ensure their genetic, physical, and physiological quality. However, between 2015 and 2022, the origin of the seeds cultivated by producers was, on average, 44% labeled seeds (certified and commercial), 40% seeds produced and reserved by the producer for their own use, and 16% illegal seeds. Unlike labeled seeds, the quality of self-produced seeds is unknown. The management of seedbeds and the conditions of the production environment from grain filling to harvest are some of the factors affecting the acquisition of superior-quality seeds. The objective of the study was to assess the quality of seeds reserved by producers for their own use during the 2018-2019 harvest. To achieve this, five different agricultural and climatic regions were established, and the environmental conditions during grain filling to harvest were related to seed quality in each region. Germination, viability, vigor, damage from bugs, environmental damage, and mechanical damage were studied. Additionally, varietal identity was assessed using two indirect estimation methods. The study revealed differences in germination between regions primarily due to environmental damage and bug damage, which in some regions exceeded 6%, the limit set for superior-quality seeds. This indicated poor management of seedbeds in controlling bugs and determining the optimal harvest time. The results of the varietal identity analysis could be improved by using the replica method, as this method detected a higher percentage of contaminated samples (7%) compared to the general visual observation of the sample, which was 0.4%.

Evaluación del banco de semillas y reclutamiento de la especie exótica invasora tojo (Ulex europaeus L.) en un predio ganadero de la región este del país

Joaquín Brito del Pino Castellanos — 2024-10-04

Ulex europaeus, also known as “gorse”, “common gorse” or “prickly broom”, is listed as one of the four invasive exotic plants of greatest risk for Uruguay. Its distribution in the country is mainly concentrated in the east and northeast of the country. This invasive exotic species (IAS) decreases the productivity of natural fields and interferes with the use and exploitation of the soil. Given the invasiveness of the species, we seek to provide knowledge about the long-distance sexual dispersal strategy. The objective of the work was to analyze the seed bank and recruitment of seedlings of the U. europaeus species based on a spatial gradient, from an area with gorse patches to 35 m away from the patches. The specific objectives were: i) to quantify the size of the seed bank and the density of seedlings in a non-invaded area adjacent to U. europaeus patches, and ii) to estimate the density of seedlings on the outer edge of the U. europaeus patches. For this purpose, two surveys were carried out on a livestock farm in the Lavalleja department (34°08'03.1"S, 55°13'01.5"W). In the first, the number of seedlings was counted and for the seed bank, soil samples were taken from 3 m from the outer edge of gorse patches up to 35 m. Ten 30-m-long transects were made across a slope and measurements were taken every 10 m. In the second sampling, an area on the edge of gorse patches was evaluated by making a 30-m border with 15 points, located 2 m apart, where seedlings were counted. In the first sampling, no seeds or seedlings were found at 0, 10, 20, 30 m from an area of U. europaeus patches. However, the presence of seedlings was observed in a patch border area at a density of 21 seedlings/m2). We can confirm that at this site and according to the literature, seed dispersal would occur in the surroundings of the mother plant, and that dispersal over a distance greater than 3 m would be an unlikely event. Dispersal over greater distances would be rare events and the agents of which are still unclear. The present study seeks to make visible the importance of controlling and preventing IAS and provides knowledge to understand the sexual dispersal of U. europaeus.

Utilización de raigrás (Lolium multiflorum CV. Bill Max) en la alimentación de terneros

Alfredo Nicolás Díaz Facchin — 2024-10-02

The objective of the work was to evaluate the effect of grazing intensity, regulated through the forage supply (kg dry matter/100 kg live weight) of a ryegrass pasture (Lollium multiflorum cv. Bill Max) on animal growth, winter meat production per unit area, and forage utilization efficiency. The experiment was carried out in the Intensive Meat Production Unit located at the Experimental Station Dr. Mario A. Cassinoni (EEMAC) Faculty of Agronomy, Paysandú, Uruguay. It was carried out between May 20 and September 3, 2022. 48 Hereford calves, born in the spring of 2021, belonging to the EEMAC breeding herd, were used. They began the experiment with an average live weight of 121 ± 31 kg, these being drawn into 12 groups (after stratification by live weight) and then randomly assigned to the different treatments defined by the supply of forage, which were 2. 5;5.0;7.5;10.0; kg DM/100 kg live weight. Each treatment was composed of 3 repetitions made up of 4 calves grazing an independent plot. Rotational grazing was carried out in occupied plots for 7 days, and then returning to them based on the accumulated biomass. During the experimental period, no significant effect of treatment was detected (P>0.05) on availability and pre-grazing height, as well as on chemical composition. The remnant and its height presented a quadratic response (P<0.01), where the 10% forage allocation resulted in the greatest remnant and its height. The use of forage presented a negative quadratic response, with the lowest utilization value being given in the allocation of 10%. The average daily live weight gain increased linearly compared to forage supply (P<0.01) where for every 1% increase in forage allocation, the average daily gain increased 79 g. On the other hand, beef production per hectare presented a quadratic response, maximizing production with an allocation of 8.06%.

Estrategias de alimentación en sistemas pastoriles intensivos de producción de leche contrastantes en inversión de infraestructura y simplicidad operativa

Micaela Abril Picco Vargas — 2024-09-26

This study was conducted at the Centro Regional Sur (CRS) of the Faculty of Agronomy, located in the department of Canelones, Uruguay. The experimental period lasted four months, comprising data obtained from August to November 2021. The objective of this research was to evaluate the impact on biophysical variables of two contrasting systems in operational dedication, animal stocking rate, feeding strategy, and production cost structure during the spring season of 2021.

A system with a stocking rate of 1.82 VO/haPP, sustained mainly with forage produced within the system (within the grazing platform), using a perennial-based forage model (excluding summer forage crops), called "low cost" (BC), with an average live weight (LW) of 483 ± 20.5 kg LW and a stocking rate of 892 kg LW/ha. On the other hand, a system was implemented where productivity (l/ha) was prioritized, which implied an increase in the stocking rate (3.06 VO /haPP), with an average LW of 465 ± 27.2 kg and a stocking rate of 1416 kg/haPP. This system, called "high productivity" (AP), required the importation of corn and sorghum silage from adjacent areas.

Feeding was based on pasture consumption, adjusted to the growth rate, supplemented with additional feed if demand exceeded supply. The available pre-grazing and post-grazing kgDM was measured with the C-Dax, allowing the calculation of pasture consumption in each paddock of both systems.

The feeding structure in BC consisted of 582 kgDM/haPP/month of forage, 100 kgDM/haPP/month of reserve, and 321 kgDM/haPP/month of concentrate, while in AP it was 780 kgDM/haPP/month of forage, 385 kgDM/haPP/month of reserve, and 540 kgDM/haPP/month of concentrate.

Milk production was 1421 and 2159 kg of milk/haPP/month for the BC and AP systems respectively. To estimate solid production, the milk composition (% fat and protein) analyzed in the Colaveco Laboratory was recorded, averaging 109 kg of solids in AP and 163 kg in BC.

The forage production of both systems showed no significant differences, being 4581 kg of DM/haPP in BC and 3772 kg of DM/haPP in AP. The overall harvest was 75% and 80% in BC and AP respectively, with an instant harvest between 25-30%. Pre-grazing and post-grazing did not show statistical differences between the systems. The average forage stock was 2498 kg of DM/haSEP in AP and 2488 kg of DM/haSEP in BC.

Selección de maíz para silo mediante familias de medios hermanos de la Raza Blanco Dentado

Pamela Stefani Ramos Olivera — 2024-09-26

Blanco Cangüé corn is an open-pollinated variety (OPV) selected by the Faculty of Agronomy and has developed through the selection of half-sib families (HSF). It has demonstrated superior performance in terms of dry matter and good nutritional characteristics for silage and grazing. The objective was to characterize the diversity within a population of white dent corn to select the best half-sib families (HSF). To achieve these objectives, statistical analyses were conducted: analysis of variance (ANOVA), chi-square test (Chi2), Tukey's multiple comparison test, Spearman's correlation, principal component analysis (PCA), and estimates of heritability and genetic gain for both quantitative and qualitative variables. The results revealed significant differences in four assessed traits and the existence of correlations between some variables. The observed variability in certain traits suggests a diverse genetic base that would be favorable for future selection strategies. PCA revealed that three components explained 52% of the total variance, increasing to 83% with seven components. Heritability values for female flowering (FF) were moderate, and for corn ear perimeter (EP) and cob perimeter (CP), they were moderate to low. The HSF method has been effective for some traits, but mass selection could be a valuable alternative for populations with high genetic variability and low heritability. Finally, 15 HSF were selected with shorter FF and higher values for CP and EP, aiming to improve flowering synchronization under water stress conditions.

Evaluación económica y ambiental de un sistema silvopastoril de Eucalyptus dunnii para obtención de trozas de diámetros finos en baja densidad

Timoteo Chamyan Kerikian — 2024-09-13

This research aims to evaluate, from both and economic and environmental perspective, a Eucalyptus dunnii plantation within a low-density silvopastoral system intended for pulpwood production. Eight permanent plots were established, each containing 30 trees, and two forest strata were identified based on topographical differences and soil types. Measurements of height (Ht) and circumference at breast height (CBH) were taken at 4,1 and 5,0 years after planting to calculate other relevant variables such as basal area (BA), diameter at breast height (DBH), and volume (V). Three trees were sampled in each plot, representing three different diameter ranges; wood density and carbon content were measured for each diameter class (DC) using spectrophotometry in the laboratory. Statistical analysis showed no significant differences in the dasometric variables (DBH, Ht, V) between the studied strata. It was found that 45,33% of the forest biomass in the silvopastoral system consisted of carbon, mainly concentrate in the tree stem. While no differences were found in the carbon percentage per individual DC, the central DC with a range of 10,4 – 18,0 cm of DBH accumulated the most carbon due to its higher frequency and final volume in the system. Carbon sequestration averaged 10,4 Tn CO_2e/ha/year over the 5 years of the plantation, while emissions from livestock were 3,5 Tn CO_2e/ha/year, resulting in a positive carbon balance of 6,9 Tn CO_2e/ha/year for the years 2017-2022. However, when considering the entire property (3.281 ha), the carbon balance was negative (-11.108 Tn CO_2e/year), underscoring the importance of expanding integrated tree systems to offset these emissions. Financial analysis demonstrated the projects economic viability, with an expected Net Present Value of $2.760 USD assuming a 6% opportunity cost and an Internal Rate of Return of 6,2%. Additionally, the positive impact of potential carbon credit generation and subsequent sale on project viability was evaluated. Considering carbon sequestration by these systems could benefit producers through the production of low-greenhouse gas emissions meat.

Biodiversidad en predios agroecológicos del Uruguay

Paola Albé Bayo — 2024-09-06

Agroecology considers that it is possible and necessary to change the predominant modes of production, moving to a model based on ecological processes, and that this can be achieved through the management of the biodiversity present in agroecosystems and surrounding systems, or agrobiodiversity. The Agroecology Network of Uruguay is an organization that brings together food producers, consumers, processors and distributors who share a vision of the impacts of agroecology in all its dimensions: social, productive and environmental.

In this work we set out to delve into the ecological aspect of the agroecosystems that make up the Network, characterizing a sample of twelve farms representative of different management styles, from the point of view of agrobiodiversity. Our objective was to generate a set of indicators that would be feasible to survey and calculate without the need for expert knowledge or laboratory equipment, and that would serve two purposes: to identify if there are differences in the expression of biodiversity among the surveyed farms, and to provide the technicians and producers linked to the Network with an accessible tool for evaluation of biodiversity oriented to decision making.

Based on the bibliographic review, seven indirect indicators and one direct indicator of biodiversity that meet the requirements of ease of measurement, ease of interpretation and scientific support that supports their relevance, were selected.

Having applied the indicators to the farms of the sample, we can draw three conclusions: 1) the values of all the indicators are better than those calculated in organic and low-input European farms, which indicates that, for the analyzed farms, agroecological principles and their associated practices are effectively applied from the point of view of biodiversity; 2) there are differences in the values of the indicators between the selected farms; 3) these differences are largely explained by the different application of agroecological practices in farm management.

Estimación de biomasa disponible mediante imágenes multiespectrales adquiridas con un dron

Nicolás Agustín Caraballo Barboza — 2024-09-05

In Uruguay, pastures are essential for livestock and dairy farming, allowing for competitive and differentiated production. However, pasture monitoring is not a common practice in establishments, as it requires a methodology to manage and improve the efficiency of the system through decision-making. Normally, this is done using direct and indirect methods, which require greater dedication and higher costs. The objective of this work is to estimate the available biomass using multispectral images acquired with a drone. Subsequently, achieve its application for decision-making through the monitoring of state variables (Stock), in the grazing area of two intensive pastoral-based milk production systems, for the winter season. The work was carried out at the Southern Regional Center (CRS) of the Faculty of Agronomy (FAgro) in 2023 in the months between June and September. A DJI Phantom 4 Multispectral drone was used in a second-year Dactylis pasture mixed with Alfalfa. The work consisted of two experiments called “drone calibration” and “AP flights”. In the first, weekly flights were carried out for 3 months in two 6x4m test plots, in which 22 50x30cm cuts were made each week in which the biomass within the quadrants (KgMS/ha), height (cm) and NDVI were determined, thus generating data for 7, 14, 21, 28 and 35 days of growth. The data were analyzed using a 2nd degree polynomial regression model correlating the variables available biomass and height with the NDVI to determine its goodness of fit using the regression coefficient. The correlation between NDVI and available biomass (kgDM/ha) showed a correlation of 0.41 (R²), although with variations in the different growth stages. On the other hand, the correlation between NDVI and height presents an R² of 0.29. Regarding the “AP flights” experiment, using the model from the first experiment, flights were made in the CRS Grazing Area (AP) with the purpose of estimating the forage stock and comparing it with another method (C-Dax). The flights were made with overlaps of 20%. The average stock values in the AP were 669 to 831 KgDM/ha and a difference with the values estimated with the C-Dax of +/-1700 KgDM/ha throughout the study period. In conclusion, for this work, and based on the experiments carried out, the drone reflected average correlation data for a Dactylis and Alfalfa pasture in winter conditions, but it provides a first approximation to what could be an important technological advance and the first precedent in terms of biomass estimation with this methodology in the AP.

Cuantificación del contenido de carbono orgánico del suelo, densidad aparente y pH, bajo dos estratos arbóreos del área protegida “Esteros y Algarrobales del Río Uruguay”

Albertina Maya Cros — 2024-08-30

The increase in greenhouse gases due to the burning of fossil fuels and changes in land use has triggered climate change, seriously impacting ecosystems, biodiversity and human life. In this context, forest soils play a fundamental role due to their capacity to capture carbon from the atmosphere through plant biomass and soil organic matter (SOM). Forest cover not only increases the availability of biomass, but also contributes significantly to the storage of soil organic carbon (SOC).

Changes in land use and cover, such as deforestation and forest degradation, can increase the mineralization of SOM, releasing large amounts of CO2 into the atmosphere. Protected areas allow the conservation of forest cover and its capacity to store carbon, thus reducing its emissions.

The main objective of this work was to quantify the SOC stock of a protected area. Specifically, the variation in SOC was evaluated in two contrasting types of forest cover: one with a high density of trees on soils without high levels of exchangeable sodium, and another with a low density on halomorphic soils. For this purpose, soil samples were taken, and bulk density and pH were also measured. From the results obtained, it can be established that the dense stratum on Brunosol shows a higher SOC compared to the sparse stratum on a Solonetz soil, highlighting the indirect influence of soil characteristics on SOC. In both strata, SOC decreases with depth, being higher in the dense stratum on Brunosol due to soil characteristics and Na content. The sparse stratum on a Solonetz showed greater compaction due to the effect of sodium content. The sparse stratum, with a higher pH, shows a positive relationship with the frequency of the Neltuma and Vachellia species.

Evaluación de deriva de fitosanitarios en aplicaciones terrestres

Matías Fernando Cornú Membredes — 2024-08-29

The application of pesticides is a fundamental practice to achieve maximum yield, making it necessary to optimize results while considering environmental care, such as adequate crop coverage, minimal crop damage, and accessible costs. Drift of spray pesticides is one of the main causes of unintended damage, which is why these chemical products must be applied with efficiency and effectiveness due to their complexity and hazardous nature. The objective of this work was to evaluate the drift of terrestrial applications of pesticides using different application technologies, droplet sizes—Fine, Medium, and Extremely Coarse—under two different meteorological conditions and different height spray boom, according to an adaptation of the standard ISO/FDIS 22866. Two experiments were conducted in the department of Paysandú, at the “Dr. Mario A. Cassinoni” Experimental Station (EEMAC), Ruta 3 Km 363, from May to August 2022. The experimental design of both experiments was a completely randomized design, with sampling at different distances from the applied area. The number of replications was 3 and 2 for experiments 1 and 2, respectively, corresponding to the pass of the spray tractor. The spray boom height was 0.8 m in experiment 1 and 1.20 cm in experiment 2. A decrease in the total accumulated drift at 100 m was observed when using drift-reducing nozzles: 25% reduction at a boom height of 1.20 m with an average wind speed of 9 km/h and without significant difference for the bar height of 0.8m and average wind of 4.5 Km/h.

Evaluación del rendimiento de materia seca en alfalfa con pastoreo, bajo diferentes manejos del riego

Julieta María Arispe Lozano — 2024-08-29

The present work was carried out at the CRS (Southern Regional Center), of the Faculty of Agronomy and its main objective is to estimate irrigation management for the alfalfa species so that it achieves a performance that justifies the inclusion of irrigation in pastoral systems.

The enormous variability of rainfall, together with the low available water storage capacity of the soils in our country, determine periods of frequent water deficit throughout the year. These deficits intensify in the summer season due to the high water demand by crops and pastures.

Likewise, climate change determines extreme events, such as droughts, which are triggered more frequently by altering production in dryland production systems.

Supplementary irrigation provides stability and increases the productivity of pastures in livestock and dairy systems. It is necessary to define its management that ensures optimal use of rainfall and allows high yields to be obtained when irrigation is included in the system. The inclusion of this management practice may be sustainable over time if rational use of water and energy is carried out.

In addition to this, it is relevant to evaluate the effect of irrigation in conjunction with grazing.

The treatments analyzed were: frequent irrigation, which was watered when 30% of the available water was exhausted, spaced irrigation, which was watered leaving up to 65% of the available water exhausted, and dry land, which only received rainwater.

The evaluation period was winter and spring 2022, summer and autumn 2023. The experimental design used was complete randomized blocks with four repetitions.

The accumulated forage yield for the evaluated period did not show significant differences between the irrigated treatments, however, there were differences between the irrigated (T1 and T2) and the dry (T0). After a borderline drought in the summer, the seasonal forage yields of alfalfa mark a clear advantage of irrigated treatments well above the rainfed treatment.

Efecto de la suplementación con grano de lupino (Lupinus angustifolius) en régimen de autoconsumo sobre la performance de novillos pastoreando sorgo forrajero

Emiliano García Borges — 2024-08-27

The presented work was carried out at the Mario A. Cassinoni Experimental Station (EEMAC) of the Faculty of Agronomy, University of the Republic, located in the department of Paysandú, Uruguay. It was conducted between January 10 and March 7, 2023, with the aim of evaluating the effect of supplementation with broken lupin grain (Lupinus angustifolius) under a self-feeding regime on the productive performance and feed efficiency of Hereford steers grazing on forage sorghum. Sixty-four Hereford steers weighing 246 ± 38 kg of live weight (LW) were blocked by live weight (light, medium, and heavy) and randomly assigned within each block to one of two treatments: forage sorghum grazing without supplementation (control, C); grazing on sorghum plus supplementation with broken lupin grain offered ad libitum (supplemented, S). Each treatment consisted of 3 replicates, each composed of 10-11 steers grazing an independent plot. The performance variables evaluated were weight gain, dry matter intake, feed conversion efficiency, ingestive behavior, and consumption pattern. The animals grazed in weekly strips with a forage allocation of 8% of LW, being moved daily to a pen with water and shade from 10:00 to 17:00 h, during which time they had ad libitum access to lupin. Supplementation did not affect the height and botanical composition (p-value>0.05) of the offered forage. Grazing activity was not significantly affected, and no differences were detected in forage utilization. Supplementation improved average daily gain (ADG) (0.971 vs. 0.554 kg/a/d, p-value>0.05), resulting in a supplementation response of 0.417 kg/d more for the animals consuming lupin and a supplement conversion efficiency (SCE) of 6.8:1. Supplement intake under the self-feeding regime was 1.03% of live weight.

Efecto de la aminoetoxivinilglicina, el 3-5-6 TPA y el ANA en la caída y madurez precosecha de manzana Cv. Cripps Pink

Marcia García de Cabrera — 2024-08-23

Preharvest fruits drop is a problem present in Cripps Pink apple, a cultivar that increases its area annually in Uruguay. One management alternative to overcome this problem is the application of preharvest growth regulators. The present work evaluates the effect of aminoethoxyvinylglycine (AVG), naphthaleneacetic acid (ANA) and 3,5,6-trichloro-2-pyridyl-oxyacetic acid (3-5-6 TPA) on preharvest fruit drop and internal quality of apple. The treatments combined doses and times of application of the regulators as follows: AVG at 125 mg/L at 8 weeks preharvest (SP), AVG at 62 mg/L at 8 SP, AVG at 62 mg/L at 5 SP, 3-5-6 TPA at 20 mg/L at 8 SP, 3-5-6 TPA at 10 mg/L at 5 SP, and ANA at 17 mg/L at 5 SP. Fruits drop evaluation was carried out on floral centers with 1 fruit and with 2 fruits marked at the time of the first application, with weekly monitoring until harvest. Pulp pressure, soluble solids and starch degradation were evaluated at 2 and 1 SP. When comparing the control treatments, a greater fruit drop was observed in floral centers with 2 fruits compared to 1 fruit, 44% and 21%, respectively. The AVG at 125 mg/L and 3-5-6 TPA at 20 mg/L applied at 8 SP together with AVG at 62 mg/L and ANA at 17 mg/L applied at 5 SP showed effect on the reduction of fruits drop at 1 SP and at harvest in the floral centers with 2 fruits, also in the total drop (floral centers with 1 and with 2 fruits) at harvest time. No effect of the regulators was found in the 1 fruit flower centers. The effect of AVG doses on fruit retention depends on the time of application. The growth regulators did not differ from the control in the fruit maturity indicators when evaluating 2 and 1 SP. The treatments with AVG 125 mg/L-8 SP and ANA 17 mg/L-5 SP were the only ones to present a linear behavior in the fruit drop curve and did not show differences in drop when comparing the floral centers with 1 and 2 fruits at any time.

Implantación y vigor inicial en Paspalum notatum Flüggé cultivar INIA Sepé en función de la fecha de siembra sobre suelos de basalto de la región noroeste

Lucía Bóffano Chebataroff — 2024-08-20

The natural adaptation of a native species to the environment makes it an outstanding character in species with high forage value such as Paspalum notatum Flüggé, an appreciable component of our natural grasslands. Knowing the characteristics of their requirements in the implantation process, their behavior in the face of variations in management variables, such as the sowing date, are fundamental steps in experimentation in the domestication process of these resources.

This work was carried out at the “El Junco” farm located 18 kilometers from the local road of Route 31, km 53, in the Colonia Antonio Rubio of the Department of Salto. The experiment period spanned from January to August 2017. The objective was to evaluate the establishment and initial vigour of Paspalum notatum Flüggé clone TB42 (cultivar INIA Sepé), as well as to determine characteristics in the partition of photoassimilates between the aerial and underground part against the variation of the sowing date. Of the cultivar planted in sowing date was evaluated, by sowing in three dates: January 17, March 8 and April 4, 2017. Non-destructive sampling was carried out at 30, 60, 90 and 120 days after sowing; monitoring number of plants per meter, number of tillers per plant, number of leaves on the main tiller and length of the main. In turn, on the last two sampling dates (90 and 120 days post-sowing), weight of the aerial part and weight of roots, were monitored.

The sowing date modifies the morphological characteristics duetovariation in environmental conditions such as soil temperature and soil water content change. The sowing date that had the best performance in the experiment was January, when the species is still in its growing season. If sowing is done in autumn, it is recommended that it be done early, trying to avoid low temperatures. The partitioning of photoassimilates did not differ significantly among the sowing dates, a result that was probably due to the low sample size monitored at those times.

Caracterización de la dormición de diferentes materiales genéticos de papa (Solanum tuberosum) y su respuesta al ambiente de almacenamiento

Mathias González Rodríguez — 2024-08-09

The objective of this work was to contribute to the knowledge of potato seed management by studying dormancy and its evolution during the storage of three different genetic materials (INIA Kiyú, Red Magic and INIA Arequita). The effect of three contrasting environments (shed, 20 °C and 30 °C) on the dormancy of seed tubers was analyzed. Different evaluations were carried out: weight loss, dormancy rupture (through the use of thermal time), sprouting and sprouting type and sprout growth rate. Weight loss was greater in the environments of 20 °C (Biotrón) and 30 °C (solarium) compared to the shed . The duration of dormancy was affected by the variety and the temperature of the storage environments, with INIA Kiyú being the genetic material with the lesser dormancy, needing fewer days (33 days) to reach 80% sprouting (reference threshold) followed by INIA Arequita and Red Magic. Additionally, it was a clear difference between 20 and 30 °C environments (chamber and solarium respectively) compared to the shed. In the latter it was not possible to release dormancy, achieving low percentages of sprouting towards the end of the experiment. The type of sprouting was affected by the storage environment. At 30 °C, multiple sprouting was stimulated. INIA Kiyú and Red Magic showed more tendency to multiple sprouting, on the other hand, INIA Arequita had more apical dominance 87%, 71% y 44% a los 36, 41 y 48 DDi respectively. Regarding the growth rate, the controlled environments (chamber and solarium) stimulated the growth of sprouts in the seed tubers compared to the shed. Longer shoots were obtain at 20 °C compared with 30° C environments.

Dinámica del cambio técnico

Delfina Peirano Peñalva — 2024-08-02

Ryegrass (Lolium multiflorum) is one of the annual grasses used as winter forage, with approximately 600.000 hectares sown annually. Its ability to produce a large amount of high-quality forage in a short time makes it highly valuable. Promoting the natural reseeding of ryegrass is a common practice to regenerate the crop annually at a low cost. This involves allowing the ryegrass to seed and then stimulating and enhancing spontaneous germination from the soil seed bank.

The general objective of this study was to evaluate the promotions of ryegrass in Uruguay and to profile the producers who adopt this technology. Specifically, it aimed to determine common techniques, the advantages and limitations of the practice, and to characterize the profile of the producers.

Two methodological tools were used: i) surveys conducted with a group of 26 technical advisors and extension agents, and ii) in-depth interviews with a group of 5 technicians and a group of 5 producers. The surveys covered aspects from the working region to the management of promotions, while the interviews, conducted via Zoom, delved into technical and productive issues.

The results suggest that ryegrass promotions are an innovation developed by producers through observation and experimentation. They are more common in livestock areas than in agricultural ones. The producers who adopt them are diverse, predominantly livestock farmers who integrate cultivated pastures into natural field systems, with limited access to machinery.

The promotions are notable for their low cost and simplicity, but have weaknesses such as unproductive areas in summer, weed problems, and lack of long-term stability. Management practices vary, from completely closing the paddocks for seeding to reducing the load without completely removing grazing. It is generally recommended to maintain good summer cover and avoid grazing in summer, although this is not always followed. Weed elimination, crucial for replanting, is achieved mostly with herbicides, and to a lesser extent with intensive grazing or mechanical control. There was significant variation in the timing of this control.

Knowledge gaps were identified in the agronomic and social aspects of ryegrass promotions, suggesting the need for institutional approaches to improve the practice and mitigate its disadvantages.

Estudio de la respuesta de la gramínea estival Eragrostis teff a diferentes dosis de nitrógeno y su relación con el ambiente hídrico

Joaquín Restaino Marziotte — 2024-08-01

Uruguay has a total grazing area of 14.3 million hectares, with 80.9% corresponding to natural grasslands and 19.1% to annual forage crops and pastures (Oficina de Estadísticas Agropecuarias, 2021). Annual forage crops are fundamental elements in the dry matter production system; they provide high-quality forage production in short periods of time and successfully reinforce forage delivery during critical winter and summer periods when perennial species decrease their productivity (Carámbula, 2002). Eragrostis teff is a summer annual C4 grass species with limited diffusion in the region, and there are no national studies on the species. Therefore, this study proposes to investigate the performance of Eragrostis teff in biomass production, as well as botanical variables and its overall performance under different water conditions (irrigation and rainfed), and its relationship with different nitrogen doses. In summary, based on the collected data, it can be stated that, in this research, Eragrostis teff performed well both under irrigation and rainfed conditions, a factor that did not affect the species' performance in attributes such as biomass production, botanical variables, and its relationship with different nitrogen doses. Furthermore, it was concluded that teff, with a dose of 300 kg N/ha, achieves biomass production levels that intercept photosynthetically active radiation, maximizing dry matter production, with a stable leaf-to-stem ratio throughout the cycle and consistent NDVI values indicative of healthy and dense forage.

Factores que afectan la degradación y productividad otoño-invernal de pasturas permanentes

Lucia Collares Day — 2024-07-23

The objective of this study was to evaluate the effect of crop-pasture rotations on the persistence of sown pastures and animal performance.

The experimental site is located at the Palo a Pique Experimental Unit of INIA Treinta y Tres in Uruguay. Two rotational treatments were included: The long rotation (LR) is a 6-year forage crop-pasture rotation, with 2 years of crops (oats - forage sorghum - ryegrass – moha) followed by 4 years of a mixed perennial pasture (tall fescue (Festuca arundinacea), white clover (Trifolium repens) and birdsfoot (Lotus corniculatus)). In this system, the livestock production strategy involved backgrounding and finishing 60 steers. With 24 steers used for the purpose of this experiment. The short rotation (SR) is a 4-year forage crop-pasture rotation, including the same sequence of crops as in the LR. However, the pasture phase lasts 2 years, with one half composed of Lotus corniculatus and Trifolium pratense and the other half composed of Trifolium pratense, Holcus lanatus and Cichorium.

The livestock production strategy in this system involved backgrounding 19 heifers and finishing 23 cows. The variables analyzed were measured monthly from March to September 2022. Pasture measurements included the forage existence, growth rate, and forage production in a monthly and seasonal basis, missing or consumed forage, harvest efficiency, and occupation time. Animal evaluations included liveweight gain, average seasonal and annual animal supply, daily weight gain, conversion efficiency, forage balance, and production of liveweight per hectare (LW/ha).

Análisis de la trayectoria de los sistemas de cultivos implementados en la región agrícola de Uruguay a partir de registros de productores

Diego Martin Baccino Costa — 2024-07-19

In recent decades, the region has experienced significant changes in its agricultural landscape, influenced by various socioeconomic and environmental factors. The expansion of soybean cultivation, along with the adoption of intensive agronomic practices, has altered land use and posed challenges in terms of sustainability and environmental management.

This study aimed to analyze the evolution of agricultural land use in the region and its impact on biodiversity. An analysis of global indicators over time was conducted, allowing us to understand the trajectory of different cropping systems.

The results reveal a trend towards greater intensification and increased uniformity of systems. The findings provide a detailed view of the evolution of cropping systems, showing increased land use intensification and greater system uniformity. These findings are essential for informing agricultural policies and management practices that promote sustainability and resilience in the Uruguayan agricultural sector.

Characterisation of genetic diversity in maize landraces of Uruguay and Brazil

Victoria García da Rosa Ruétalo — 2024-07-15

Maize landraces are highly dynamic populations and at the same time a tool for conserving genetic resources and generating diversity. Information on maize diversity in Uruguay and Brazil was updated in a new reclassification of South American lowland landraces, however, this study did not address the area of cytogenetics. Chromosomal knobs are blocks of heterochromatin that stain differentially and have been used to cytogenetically characterise different maize genotypes. The aim of this work was to characterise the genetic variability of maize landraces from Uruguay and Brazil using cytogenetic techniques, based on the study of the number and size of knobs, percentage of heterochromatin and presence of supernumerary B chromosomes (Bs). Thirty-six accessions of maize landraces classified into 21 races were studied. The analysis of number of knobs and presence of Bs were performed on mitotic metaphase chromosomes by DAPI fluorescence banding. Significant variation was observed in the number of knobs for dent and floury maize, and great variability in the percentage of heterochromatin, in addition medium to large knobs were found in all the individuals analysed. The races also showed great variability in terms of number of knobs and heterochromatin percentage, although not significant. In the results obtained, the difference in the frequency of Bs stands out, 0.25 for Uruguay and 0.025 for Brazil, being the first record made for a group of maize landraces for both countries. In conclusion, there is intragenomic variability in the number of knobs and percentage of heterochromatin. Moreover, there are significant differences in Bs frequencies between both countries, which may be associated with the route of maize dispersal to the lowlands.

Caracterización de los productores del centro y litoral-norte del país en función de la adopción e implementación de los cultivos de servicio

Gerónimo Cidade la Greca — 2024-07-02

Cover crops (CC) represent a technological innovation that involves the inclusion of various species in agricultural rotations, prioritizing the ecosystem and its services while maintaining the yields of cash crops. In Uruguay, since 2008, there has been a regulation requiring soils to remain covered to prevent water erosion, which is one of the main issues affecting sustainability in the country. However, the inclusion of these crops within agricultural rotations is heterogeneous, with different levels of adoption. The objective of this study was to characterize the farmers in the agricultural coastal region of Uruguay according to their level of adoption of cover crops. Specifically, the study analyzed individual variables related to the type of farmer, production system, and communication channels used, identifying patterns or trends in the collected data. A survey consisting of a series of questions reflecting variables of different natures (nominal, ordinal, continuous, categorical, discrete quantitative, nominal qualitative, binary qualitative) was conducted with 105 farmers in the region, associated with various social organizations. The information was systematized through univariate and multivariate analysis. Among the main results, it was found that the adoption of CC is partial and more common among larger-scale farmers, as these crops do not provide immediate economic returns. It was also observed that the majority of these farmers use non-owned land for production and that, although they have a background in agriculture, there is a marked trend toward diversifying production systems, primarily including livestock farming. Finally, it was confirmed that CC are not the main technological strategy adopted to meet the requirements of the Soil Use and Management Plans, as several farmers opt for other alternatives.

Consumo y eficiencia de conversión en novillos Wagyu puros en un sistema de feed lot

Matias Nicolas Alzogaray Iguini — 2024-06-13

The objective of this work was to evaluate the consumption and conversion efficiency of pure Wagyu steers with the addition of a lipid component in the diet. The database for this study was 32 animals belonging to the “El Oriental” cabin, located in the city of Mercedes, fed based on wet and dry diets. For the statistical study, analysis of variance and Tukey tests were performed and the data were analyzed using the MIXED and GLM procedures of the SAS program. The results obtained indicate that there are individual differences in consumption when they are fed the same diet, possibly explained by dominance relationships. Likewise, significant differences were found in food consumption when the steers present a change in the composition of the diet. On the other hand, it was not possible to conclude in relation to the conversion efficiency due to variability in consumption and weight gains.

Evaluación productiva de sistemas pastoriles de producción de leche en estrategias de bajo costo y alta productividad para la estación de invierno

María Pía Briñón Ghione — 2024-06-07

The reality faced by Uruguayan dairy producers is challenging given the global context, marked by fluctuations in milk prices and production inputs. This scenario presents both challenges and unique opportunities for each system, underscoring the need to explore new frontiers in managing livestock and feeding strategies to enhance the competitiveness and sustainability of this sector. For this reason, the current experiment, framed within a project of the Red Tecnológica de la Cadena Láctea (RTCL), aimed to evaluate two contrasting productions assessed at the farm system level (farmlet). One was a low-cost (LC) strategy aimed at greater operational simplicity with low production costs, with a stocking rate of 1.8 milking cows per hectare of platform, and the other, called high productivity (HP), aimed to achieve high milk production per hectare with a stocking rate of 3.0 milking cows per hectare of platform. Fieldwork covered the months between June and August 2023 and was carried out at the Centro Regional Sur, in Canelones, Uruguay. The variables examined for both systems included forage production and harvest per hectare, forage stock, availability at pre- and post-grazing times, confinement times, grazing opportunities, feeding structure, and individual and per hectare milk production. Pasture measurements were taken weekly using the C-Dax and RPM tools, with results analyzed utilizing a Completely Randomized Block Design. Confinement times, feeding, and milk production variables were analyzed using a Completely Random Design. The results indicated that during the winter season, no significant differences were observed between treatments regarding forage production and harvest per hectare or forage stock, which can be explained by grazing and supplementation management. However, distinctions emerged in feeding structure, confinement times, and grazing opportunities, with the AP system exhibiting a greater reliance on diet supplements, lengthier confinement periods, and fewer grazing opportunities. This aligns directly with the higher productivity per hectare achieved by this system. Furthermore, differences were also found in individual milk productivity, where the BC system presented higher production, which was unexpected given the design of each system. Despite these differences, both systems achieved high forage production and harvest, with high milk productivity per hectare, making them promising strategies for Uruguayan dairy production, not only from a production standpoint but also by incorporating management and feeding strategies that require less operational demand and pressure on human resources.

Efecto de cultivos invernales sobre la dinámica del enmalezamiento invernal

Marcos Andrada Iraola — 2024-06-04

Weeds are one of the main problems of the agricultutal system. Within the integrated control of weeds, one of the strategies is the use of weed suppressing crops, thus considering those crops that, due to their wrowth and development characteristics, or their allelopathic potential, are capable of reducing the proliferation of weeds. The objetive of this work is to study the effects of different winter crops on the biological processes (establishment, growth, development and reproduction) of weeding. The crops used were wheat, barley, rapessed and oats. In each evaluation the number of plants of each weed species and their stage of development were recorded. A significant variation in the dynamics of weeding as well as its biological processes could be observed between the different winter crops, attributed to the characteristics of each crop in conjunction with the management of herbicides, which suggests the importance of considering these aspects for effective control of weeds in winter crops.

Evaluación de estrategias de alimentación en sistemas pastoriles de producción de leche de alta productividad y bajo costo operativo durante la estación de otoño

Mariana Viera Barreira — 2024-06-03

The work was carried out in the department of Canelones, in the town of Progreso, on Folle road, Km 35,500, in the Southern Regional Center (CRS), belonging to the Faculty of Agronomy. The evaluation period covered from March 20 to June 20, 2023. The objective of the work was to compare and evaluate the effect of using contrasting animal loads in a dairy system with different feeding strategies. For the analysis, the production and harvest of forage in the platform area, direct grazing, consumption of forage reserves and supplementation needs according to the load level, animal performance in terms of milk production, solids, live weight and body condition, both individually and per hectare. Two systems that differ in the feeding and animal loading strategy were evaluated, one called High Productivity (AP) and the other Low Cost (BC). For this, two batches of animals were used, one for each treatment. The feed in general terms consisted of corn silage, corn and canola concentrate, and forage for the AP batch, and in the case of the BC batch, the corn silage was replaced by bales of ryegrass. The forage base belonged to a 6-year rotation, with a short-term meadow (2 years) and another phase of perennial pastures lasting 4 years. Regarding grazing, to estimate forage, the paddocks assigned to the experiment were visited once a week and always respecting the same day, measuring grass availability through the C-Dax pasturometer. A diagonal transect was carried out through each paddock with the C-Dax coupled to a tractor, recording the average height provided by the instrument. In this way, the forage stock and the growth rate were determined for all the paddocks, selecting those with the greatest available biomass for grazing. The days of occupancy of the strips depended on the system, since, in the case of AP, the strips were of daily occupancy, and for BC strips were created with at least approximately 3 days of occupancy. In addition to the weekly round, pre and post grazing was also measured with C-Dax, to estimate individual forage consumption per animal. The animals were milked twice a day (6:00 am and 3:00 pm). Forage consumption depended on the growth rate of the grazing area. The AP lot had 41 days of confinement and the BC 40 days, these enclosures had artificial shade and water. The systems did not show significant differences in terms of forage production, harvest efficiency, individual consumption of reserves, concentrates and forage, live weight, body condition, individual production and solids production. Regarding milk production and food consumption per hectare, a significant response to the load effect was shown.

Caracterización de la resistencia de Amaranthus spp. para el herbicida glifosato en Uruguay

Juan Antonio Calistro Martínez — 2024-05-17

The species Amaranthus hybridus, Amaranthus tuberculatus, and Amaranthus palmeri constitute the most significant weed complex in Uruguayan agricultural systems. In recent years, effective control of these species with glyphosate has proven not effectively. This study aimed to confirm the presence and level of glyphosate resistance in these three Amaranthus species, and to assess various chemical alternatives for managing resistant biotypes. To confirm glyphosate resistance, dose-response assays were conducted for each species, employing a 5x8 factorial design. Factor A encompassed 5 biotypes with varying resistance levels, while Factor B involved 8 glyphosate doses, each with four replications. Plant mortality (% control) was assessed at 7, 14, and 21 days after treatment (DAT), and aerial dry matter (Reduction in DM) was measured at 21 DAT. Resistance factors (RF) were calculated from the C₅₀ and GR₅₀ data obtained. To evaluate herbicides alternatives to glyphosate, an independent trial was conducted for each Amaranthus species with a completely randomized experimental design, and the treatments were arranged in a 5x6 factorial design where factor A corresponded to 5 biotypes of Amaranthus spp. with different susceptibility/resistance, and factor B corresponded to five herbicide treatments: diclosulam, imazethapyr, 2,4-D, dicamba, and fomesafen, along with a control (no application), with four replications utilized.. % Control and reduction in DM were determined at 21 DAT. Both sets of trials were fully replicated twice. The studied biotypes exhibited a high level of resistance to glyphosate, with RF ranging from 12 to 113 for A. hybridus, 1 to 47 for A. tuberculatus, and 4 to 30 for A. palmeri, thereby formally confirming glyphosate resistance in Uruguay. Additionally, results obtained for alternative herbicides indicated evolving resistance of different Amaranthus species to ALS inhibitors and fomesafen. However, 2,4-D and dicamba remain viable alternatives for managing glyphosate-resistant biotypes. Thus, the adoption of other chemical tools such as pre-emergent, along with herbicides featuring distinct mechanisms of action, combined with non-chemical weed management practices like cover crops, should be promoted to mitigate selection pressure and the emergence of new herbicide resistance cases in Uruguay.

Emisiones de metano en novillos Wagyu puros en confinamiento

Inés Brufao Galusso — 2024-05-17

The purpose of this study was to evaluate methane emissions in Wagyu steers at the "El Oriental" hut in Mercedes, using the Laser Methane Detection. Data were collected from 32 animals fed wet and dry diets, including the addition of lipids. Analysis of variance and Tukey tests were applied using the MIXED and GLM procedures in the SAS program for statistical analysis. The results indicated that Wagyu steers fed wet diets showed significant differences in methane production, measured in ppm/m, compared to those fed dry diets, supporting the hypothesis stated.

Evaluación del potencial como enmienda orgánica de un fermentado ácido-láctico de restos de alimentos

Geremías Evia de Castro — 2024-05-16

Lactic acid fermentation is presented as an alternative technique for organic waste processing, although little literature exists on the effects of applications to the soil. The aim of this work was to evaluate the evolution of different chemical and microbiological soil properties after the material’s addition.

For this purpose, a 101-day laboratory soil incubation experiment was carried up, which included two contrasting soil conditions (greenhouse soil and farm soil) and three doses of material
(0, 8.8 and 17.6 Mg. DB. ha^-1). Prior to incubation, soils and available materials were characterized. Destructive samples were taken at incubation days 7, 14, 28, 56 and 101 to determine inorganic nitrogen concentrations in the form of NO₃ and NH₄, pH_H2O and electrical conductivity. Concentrations of calcium, magnesium, potassium and sodium, as well as organic carbon and nitrogen total contents were measured at the beginning and at the end of incubation. Soil microorganism community’s indicators were evaluated, such as β-glucosidase and alkaline phosphatase activity, in addition microbial biomass estimation by counting., Soil respiration evolution was observed through a NaOH trap in a parallel incubation.

Differential behaviours were observed for evaluated soils, including NO₃ a net immobilization
of 28.4 kg N. ha^-1 in the greenhouse soil and a net mineralization NO₃ of 11.0 kg N. ha^-1 in the farm soil with fermented material applied in the same dose. In greenhouse soil, a pH_H2O increase was observed when applying the material, while in farm soil there was not. Meanwhile, the application of the material significantly increased the levels of magnesium and potassium in both soils.

No significant differences were observed for sodium levels and electrical conductivity with the adding of the fermented lactic acid in any case.

An increase in respiration in both soils was observed as a result of the application of the material, stabilizing after 76 days.

Estudio de la heterogeneidad estructural del campo natural sometido a dos ofertas de forraje en pastoreo continuo y rotativo

Lucas Alex Camarano Martínez — 2024-05-14

The present work was carried out at the Mario A. Cassinoni Experimental Station of the Faculty of Agronomy - University of the Republic, located on National Route No. 3 Gral. José Gervasio Artigas, kilometer 363, in the department of Paysandú, Uruguay. The study was conducted on paddock 13 (Lat -32.387511°S and Long -58.033235°W), covering an area of 37,8 hectares of restored natural grassland, where an experiment with a factorial treatment structure (2x2) is set up to evaluate two grazing methods (Continuous and Rotational) and two forage allowance levels (High and Low, with the combinations being 12% in spring-summer and 8% in autumn-winter, and 8% in spring-summer and 4% in autumn-winter, respectively). The animals used are Holando steers in the rearing phase. The forage allowance levels are adjusted monthly according to forage availability (kg DM/ha) and the expected growth rate, regulating animal loads based on monthly weighing data. The evaluation period extended from March 15 to June 23, 2023, encompassing the autumn season. The objective of the study was to characterize the structural heterogeneity and botanical composition of the natural grassland subjected to different grazing managements, relating these factors to the individual animal response obtained. For a better interpretation of the results, the area was classified into three zones - Lowland, Mid-slope, and Lithosol - corresponding to contrasting soil types, according to cartography and visual field estimation. The variables determined were forage height (cm), forage mass present (kg DM/ha), botanical composition, and average daily gains of the animals (kg LW/d). For the analysis of the results, the statistical software InfoStat was used, applying multivariate and univariate descriptive techniques (ANOVA), and the test of homogeneity of variances (Levene's Test); subsequently performing mean comparison tests using Tukey's test with a significance level of 10%. The results showed that the pasture structure (height) was conditioned by the grazing method and the zone, more than by the forage allowance level; with greater heights in the Rotational method, and according to the zone, in both grazing methods, in descending order from Lowland, Mid-slope, and Lithosol. Structural heterogeneity was conditioned by the forage supply level, and secondly, by the studied zone; with greater heterogeneity at High forage allowance levels, and in the same descending order from Lowland, Mid-slope, and Lithosol. The botanical composition was primarily defined by the studied zone, with independent responses according to the grazing method and forage allowance level; observing contrasting sets in vegetative and productive types, according to these latter two factors. The average daily gains of the animals did not show significant differences according to the applied treatments.

Uso de cultivo de cobertura y laboreo reducido sin utilización de agroquímicos en horticultura

Rodrigo Arana Ruiz — 2024-05-13

The soils traditionally used for horticultural production in our country have undergone erosion and degradation processes. The high frequency of tillage and low soil cover, low organic matter input to the soil, problems with systematization and excessive use of agrochemicals largely explain the acceleration of these processes. The sustainability of productive systems depends on the development and application of techniques and/or technologies that aim to reverse the deterioration. The use of cover crops and reduced tillage (CC-RT) can promote soil health and functionality, but its applicability in systems aiming to reduce the use of agrochemicals is challenging. The general objective of this work is to contribute to the generation of knowledge that allows for the feasibility of using CC-RT technology without the use of agrochemicals in vegetable systems. For this purpose, two tillage practices were compared for soil preparation prior to onion transplantation: conventional tillage (CT) and reduced tillage (RT) at three sites. The variables analyzed included: quantity and quality of cover crop biomass, weed biomass and soil cover, soil mineral nitrogen (SMN), onion crop biomass, foliar nitrogen concentration (FN), and soil coverage. The aboveground biomass production of cover crops ranged from 3.9 to 7.1 Mg dry matter ha^-1, with higher biomass and weed coverage in RT, lower SMN and FN content, reduced growth of onion plants, and greater soil coverage compared to CT. The results demonstrate the possibility of implementing RT without the use of agrochemicals. However, nitrogen availability and increased weed pressure in reduced tilled soil are limitations for its application, requiring further research to address these constraints.

Roots production, aerial biomass and nitrogen contributions of the different service crops

Enzo Martín Morán Valleo — 2024-05-03

In the first decade of the 21st century, the country went through a process of agricultural expansion, characterized by a continuous agricultural system in which soybean monoculture predominates. This practice, which involved frequent periods of winter fallow, resulted in constant exposure of the soil during the winter, causing its progressive deterioration and affecting both its physical and chemical properties. In response to this problem, service crops have emerged as a strategy to mitigate negative impacts. The main objectives of this study are to evaluate nitrogen contributions, aerial biomass production and root biomass production in the first 20 cm of soil, in different types of service crops. Different varieties and mixtures of service crops were used, including Avena byzantina, Avena strigosa, Vicia villosa, Lupinus angustifolius, and mixtures of Avena byzantina + Vicia villosa and Avena strigosa + Vicia villosa, arranged in a completely randomized block design with three repetitions. The results revealed significant differences (p<0.05) in terms of the production of aerial and root biomass of the different treatments evaluated, with one of the mixtures of Avena strigosa + Vicia villosa being the one that achieved the highest production of both aerial biomass (8045 kg DM ha^-1) and root biomass (1105 kg DM ha^-1). Furthermore, a linear and positive correlation was identified between both variables. Regarding the contribution of nitrogen, the Vicia villosa crops, as well as the mixtures of Avena strigosa + Vicia villosa, stood out as the treatments that offered the greatest contributions of said nutrient.

Actualización de la base de datos del programa Condición Corporal para la raza Hereford

Felipe Andiarena Salvioli — 2024-04-26

The objective of this work was to update the existing database of the Cond_Corp program for the Hereford breed. We proceeded to capture images with cellular phones, and their subsequent classification in the corresponding classifications, thus generating the database for the program.

The field work was carried out in the facilities of the Faculty of Agronomy of Paysandú (EEMAC). The cattle used were 177 Hereford breeding cows belonging to the breeding herd of the EEMAC. In this instance, an average of 10 photos were taken for each cow, where each one had its caravan recorded and when leaving the scale (place where the photos were taken) the three observers present diagnosed one CC per animal by visual appreciation.

Subsequently, the photos taken in the field were evaluated at the desk, selecting one for each body condition point (score from 2 to 6 every 0.25 units).

The folders (16) were added to the Cond_Corp program, adding a base of 177 images. From the total number of images, one for each point was selected to make the new visual appreciation primer, adding the intermediate scores (2, 2.5, 3 .... 6).

The updating of the image database as well as the updating of the primer are tools that contribute to help the producer in decision making in the management of breeding herds.

Evaluación de aplicaciones selectivas (WeedSeeker) en el control de malezas en barbecho

Felipe Berretta Invernizzi — 2024-04-25

The purpose of this study was to evaluate the effectiveness of weed control in fallow fields through the application with WeedSeeker. To do this, in May of the year 2023, a mixture (glyphosate + saflufenacil) was applied, with three different weed detection sensitivities of the equipment, and a control treatment (conventional application).

The application took place in paddock 4B of the Mario Alberto Cassinoni Experimental Station (EEMAC), Faculty of Agronomy, Udelar, located in the Paysandú department. This application was carried out with herbicides and the tracer Brilliant Blue for the evaluation of deposition on the weeds. After the application, 20 plants from each treatment were collected, which were washed to determine the amount of tracer in the spectrophotometer. From the weight of the plants, the deposition per gram of weed dry matter was expressed. In addition, control evaluations were conducted through observations of damage on marked weeds. The treatment effect on weed deposition was not observed, but it was observed in weed control, with slightly lower control levels in the treatment with lower weed detection sensitivity.

Estimación de biomasa de festuca mediante el uso de drone multiespectral

Juan Manuel Pérez del Castillo López — 2024-04-25

In Uruguay, both cattle raising and dairy farming use pastures as the main source of food, allowing for low-cost production and a differential product. Systematic monitoring of the availability and growth of pastures establishes a challenge in management and the search for system efficiency. There are various methods to carry out this monitoring, from direct to indirect methods and even new technologies such as drones, and from which the question arises if it is possible to carry out these measurements with the use of them, which will allow a detailed description of the space and an easy implementation. In this work, the main objective is the quantification of biomass and height of the pasture from images obtained by a multi-spectral drone and the generation of the NDVI. The measurements were carried out in the autumn of 2023 on a third-year fescue with irrigation located in the Progreso-Canelones area in the Centro Regional Sur (CRS) belonging to the Faculty of Agronomy of the University of the Republic, Uruguay.

Weekly flights were carried out during the autumn to obtain the images and their subsequent processing for the generation of the NDVI model. To calibrate the drone, a double sampling was carried out where, in addition of taking images with the drone, samples were cut from quadrants of (0.51 X 0.31m) and height was measured with a ruler. In this way, each measurement of a quadrant has a KgMS/ha and height value and then the corresponding NDVI value is assign. The correlation between NDVI and real biomass (KgDM/ha) was R²=0.74, and for NDVI and height (measured with a ruler) R²= 0.76. On the other hand, a DEM (digital elevation model) was generated through the images, from which an attempt was made to determine the height of the pasture, but could not reach accurate results, so it is a factor to continue studying and working. From the NDVI and biomass model it was also possible to generate biomass distribution maps. In this way, in this work, using the drone, it was possible to begin generating new tools that allow us to make estimates of the state variables of a pastoral system, in order to facilitate decisions when taking measures of management.

La utilizacion de raigras (Lolium multiflorum cv. Jack) en la alimentacion de terneros

Lucía Catalina Coronel Varela — 2024-04-19

The objective of the work was to evaluate the effect of grazing intensity, which was regulated through the forage supply (kg dry matter/100 kg live weight), of a ryegrass pasture (Lolium multiflorum cv. Jack) on the average gain of calves during autumn winter, forage utilization efficiency, dry matter consumption, pasture quality, and animal behavior. The experiment was carried out in the Intensive Meat Production Unit (UPIC) located at the “Dr. Mario Alberto Cassinoni” (EEMAC) Faculty of Agronomy, Paysandú; Uruguay between May 20 and September 3, 2022, totalling 106 days. Thirty-six Hereford calves, born in the spring of 2021, belonging to the EEMAC breeding herd, with an average live weight of 132.18 ± 9 kg were used. They were drawn into 12 groups (after stratification by live weight) and these randomly assigned to the different treatments defined by increasing levels of forage supply (OF): 2.5; 5.0; 7.5; 10.0; kg MS/100 kg live weight, respectively. Each treatment was composed of 3 repetitions made up of 3 calves grazing an independent plot. Rotational grazing was carried out in plots with 7 days of occupation, returning to it depending on the accumulated biomass. During the experimental period, no significant effect of the treatment was detected (P>0.05) on the availability and pre-grazing height, or the chemical composition of the forage offered (P>0.05). The remnant and the height associated with it showed a linear response (P<0.01) with the maximum remaining forage and its height found in the OF 10%. Utilization presented a negative quadratic response, with the lowest utilization value observed in the OF of 9.5%. The average daily live weight gain increased linearly with OF (P<0.001), associated with a significant increase in dry matter consumption (P<0.001) and increases in the concentration of protein in the diet, the latter evidenced by a greater opportunity for selection by increasing the supply of forage. However, no significant differences were found with changes in OF in grazing, rumination or rest activity (P>0.05) or in bite rate.

Efectos de formas alternativas de transición corral-pasto durante primavera en terneros Hereford manejados a corral (ADT) durante invierno

Milagros Bazzini Perroni — 2024-03-18

The trial was conducted to evaluate the effect of transition method (gradual vs. abrupt) when calves are moved from winter confinement to spring pasture on performance and grazing behavior. Thirty Hereford heifers with an average weight of 337.5 ± 32.6 kg were used, originating from the experimental herd of EEMAC born in the spring of 2020, fed in confinement during winter with a total mixed ration without long fiber. The trial lasted for 41 days, from November 16th to December 27th, 2021.

Calves, grouped by diet type in the pen, were assigned to two treatments based on the feeding strategy at the exit from the pen to pasture in spring: gradual transition system (STG) and abrupt transition system (STA). During the first 6 days of the trial, STA animals remained confined with the total mixed ration as the sole feed, while STG animals also stayed in the pen receiving the same ration, but additionally went out to graze a pasture with a forage allocation of 6 kg DM/100 kg live weight, starting with 2 hours of grazing on the first day and increasing by 2 hours daily. From day 7 onwards, both treatments left the pen to graze the same pasture as their sole feed in spring. Management was on a weekly strip grazing basis with equal forage allocation.

Variables studied during the trial were average daily gain (ADG) estimated by regression from live weight recorded every 7 days without prior fasting, ruminal pH, and ingestive behavior. ADG for the 41-day evaluation period was not affected by treatment (0.629 vs. 0.581 kg/day for STG vs. STA respectively, P=0.196). Both treatments showed weight loss in the first week of grazing (-0.700 kg/day vs. -2.87 kg/day, p<0.01 for STG and STA, respectively), which reversed from the third week of grazing onwards, resulting in no differences between treatments in ADG (1.16 kg/day vs. 1.11 kg/day, P=0.504, for STG and STA, respectively).

No significant differences in ruminal pH were observed due to treatment on day 1, whereas on day 7, pH was lower for STA (p<0.05). From day 14 onwards, no differences were observed due to treatment or day of measurement.

During weeks of grazing together in the pasture, there were no differences in ingestive behavior between treatments. Grazing was the main activity occupying most of the time. Over time, there was a decrease in resting time and an increase in rumination time.

These results indicate a 14-day transition phase, characterized by a negative residual effect on ADG after leaving confinement for pasture, occurring regardless of the transition method.

Efecto del rastrojo de seis cultivos de servicio y dos tecnologías de desecación en la dinámica del enmalezamiento en barbecho y cultivo de soja

Virginia Micaela Curti Cruz — 2024-03-06

During the years 2019 and 2020, a series of tests were established at the “Dr. Mario A. Cassinoni” (E.E.M.A.C.), department of Paysandú, with the purpose of evaluating the effects of six service crops (CS) black oats (Witch hazel), white oats (Avena sativa), centeno (Rye cereal), raigras (A multi-flowered lily), black oats plus vetch (A villous vice) and rye with vetch, combined with two desiccation technologies: herbicide and rolling, in weeding and soybeans. The experimental design was adjusted to a model of plots subdivided into strips, it has a random block structure with 3 repetitions with a plot size of 10 x 10 m. Each plot is subdivided into 2 equal parts, one treated with herbicide and the other with rolo. The determinations made in fallow were: dry matter production prior to desiccation, and prior to sowing soybeans; soil cover by stubble and weeds, the density, structure and composition of the weeds. At the soybean level: soybean implantation and development, stubble and weed coverage, weeding, soybean growth and development, and soybean yield. The estimated variables were processed using the INFOSTAT program, performing ANAVA and multiple comparison testing using the Tukey test (0.05). Effects of the type of CS and technology were found, as well as interactions of these effects on desiccation on weed density and weed composition in fallow and in the cultivation stage. In fallow, all CS determined similar weed densities, regardless of the desiccation technology, except Av. B with rolling, which had higher densities. Av. B and Cent. that determined low coverage of stubble and rolling, had higher percentages of fresh weeds and winter broadleaf species. The CS with low stubble and herbicide coverage anticipated summer grass weeding, behaving the same as the control. In the soybean cultivation stage, the CS that initially determined a lower percentage of stubble had a higher percentage of fresh weeds, a higher density of total weeds, total summer weeds and Echinochloa colona. The CS with low stubble coverage and with rolling had higher weed density. Weed cover was reduced by more than 50% in the CS that achieved 50% stubble coverage compared to the control without previous CS. In soybeans, effects of the previous CS, the desiccation technology and the interaction of both effects were detected. With low stubble coverage, rolling determined less soybean implantation than herbicide application, but without changes in development. Allelopathic effects of Av. N and Rg could have been evident, affecting the emergence and/or development of soybean. Soybean yield was more affected by the combination of high stubble coverage and its allelopathic effect on soybean growth and development, as was the case of Av. N.

Evaluación productiva y ambiental de un sistema silvopastoril de Eucalyptus grandis con destino a madera sólida

Joaquín José Echeverrigaray Quillet — 2024-03-01

In a pastoral-driven nation such as Uruguay, the interrogation of greenhouse gas emissions emanating from the livestock sector has instigated profound consternation. In this context, it is crucial to assess the carbon balance and financial viability of a system that integrates forestry and agricultural production, such as silvopastoral systems. Through a case study in the central-southern region of the country, the carbon quantity in an 11-year-old Eucalyptus grandis plantation was determined. The plantation had a teorical planting density of 625 trees/ha and underwent various silvicultural treatments to achieve a final population of 154 trees/ha pruned up to 6 m in height. Eleven permanent plots were established in two strata (Silvo Norte and Silvo Sur), where two inventories were conducted. For each tree, height and diameter at breast height were measured, and subsequently, basal area and individual volume were calculated to obtain these parameters per hectare. Samples were taken from three trees in each plot, representing three diameter classes, processed in the laboratory for wood density and carbon content using spectrophotometry. The results reveal a superior performance of Silvo Norte compared to Silvo Sur, with an average carbon percentage in the stem and bark of 40,67%, over a volume of 100,5 m³/ha (9,28 m³/ha/year). This translates to an annualized capture until 2023 of 12,2 tons/ha/year of CO₂ equivalent. Contrasting this capture with livestock emissions calculated from IPCC equations (Hongmin et al., 2006) estimates a carbon balance of -5,49 tons CO₂e/ha/year in the entirety of the silvopastoral system. These results validate the carbon sequestration potential in an integrated livestock and forestry system. This enhances the reliability of a potential carbon credit system. Regarding the financial analysis, the system yielded a Net Present Value of 210.415 U$D, considering a 7% opportunity cost, proving to be economically viable. Additionally, the calculated Internal Rate of Return was 9,07%. An analysis of the impact of carbon credit sales on the project's viability was also conducted, improving the values mentioned above. The obtained results demonstrate the environmental sustainability and economic viability of the system.

Evaluación de volumen real en suelos de prioridad forestal de Eucalyptus grandis W.Hill ex Maiden, Eucalyptus dunnii Maiden, Eucalyptus smithii R.T.Baker y Eucalyptus benthamii Maiden & Cambage

Franco Devitta Romero — 2024-02-28

The objective of this work was to calculate the real volume and shape factor of different species of Eucalyptus, through different cubing methods such as Smalian, Huber, Newton and Hohenadl and to make the respective comparison. The volume calculation was carried out from measurements of a series of dendrometric variables of interest such as total height, diameter at breast height and diameter at different heights, in a trial of 15-year-old Eucalyptus trees, constitute of four species: E. grandis, E. benthamii, E. dunnii and E. smithii of seminal origin, in the department of Tacuarembó, Uruguay. The data was obtained through field measurement from a sample of individuals of the entire trial. This data was obtained by cutting and cubing the previously selected individuals from diameter classes generated for each species. The data analysis was carried out using the R statistical software, in its RStudio interface, through the adjustment of linear models, analysis of variance, comparison of means by Tukey and residual analysis. Regarding the actual individual volumes with bark, for E. grandis statistically significant differences were obtained (p-value of 1.29e-06) with respect to the other species presenting the largest volume, with 1,821 m3 per tree. For the volume without bark, it is observed that E. grandis differed significantly (p-value 1.4e-06) from the rest by presenting the highest value for the variable with 1.6817 m3 per tree, while E. smithii presented the lowest value 0.8530 m3 per tree. In relation to the form factor with bark, there were significant differences between all species 0.52; 0.48; 0.43 and 0.41 for E. grandis, E. benthamii, E. smithii and E. dunnii respectively, (p-value of 2.5e-10). For the form factor without bark, it was observed that there were significant differences between E. grandis and the other species (p-value of 6.83e-11), with this species presenting the highest value 0.5203 and E. smithii being the species that presented the lowest value for said variable 0.4639. In relation to the estimation by the methods, for the volume without crust, there were significant differences between the Hohendahl and Huber methods but not between them with Smalian and Newton, while in the estimation of volume with bark, there were no differences between them.

Efectos del déficit hídrico sobre variables hídrico-funcionales en Eucalyptus grandis e híbridos interespecíficos

Juan Ignacio Villar Tregarthen — 2024-02-28

Afforestation with Eucalyptus species occupies over a million hectares in Uruguay, with E. grandis being one of the most cultivated species. The increasing frequency of drought and heat waves in the region raises the need to evaluate hybrids with red gums (E. camaldulensis and E. tereticornis) since they are known to sustain gas exchange and growth even under severe drought conditions. Hybrids with E. urophylla are suitable for humid-subtropical regions. This study aimed to compare the effects of water restriction (WR) on plant water status, hydraulics, and growth of E. grandis (one clone; GG), E. grandis × E. camaldulensis (one clone; GC), E. grandis × E. tereticornis (one clone; GT), and E. grandis × E. urophylla (two clones; GU1 and GU2). Two drought-stress cycles were applied to six-month rooted cuttings from mid-spring to early fall under greenhouse environmental conditions. Predawn (Ψpd) and midday (Ψmd) leaf water potential, relative leaf water content (RWC), stomatal conductance (gs), and plant height and diameter were measured across each cycle. Daily fluctuation of Ψ was calculated as ΔΨ = Ψpd - Ψmd. Pressure-volume curves were performed to calculate the elastic modulus (Ɛ) and the osmotic potential at turgor loss (Ψπ₀) and full turgor (Ψπ_t). Specific (k_S) and leaf-specific (k_L) branch hydraulic conductivity, specific leaf area (SLA), and chlorophyll content (SPAD) were measured at the end of the second drought-stress cycle. Percentage loss of hydraulic conductivity (PLC) was calculated after removing the xylem embolism. Red-gum hybrids (GC and GT) had higher cavitation (PLC) under drought, as a consequence of maintaining high ΔΨ to sustain transpiration and carbon fixation. They showed elastic adjustment in WR, and osmotic adjustment was observed in the E. grandis clone (GG). GT clone showed a three-fold increase in cavitation and had 1.5 times stomatal opening (gs) than the most drought-sensitive clone (GG), exhibiting the lowest reduction (17%) in diameter growth under WR. GC hybrid attained the highest height at the end of the study (40% higher than GG) and GU clones reached the highest diameter. GT and GU2 increased by 25% the SLA in WR and GC clone did not show difference. GC and GT had higher chlorophyll content in WR, suggesting an “hormetic” response. Correlations among functional variables are explored, and the water supply capacity to the foliage among clones is discussed to better understand drought resistance strategies and growth performance of the different taxa.

Análisis y caracterización botánica del Arboretum Krall de la Estación Experimental Bernardo Rosengurtt

Sofia Arambillete Rosa — 2024-02-15

The IABG considers arboreta as places open to the public where plants are labeled and highlights those that universities maintain for teaching and research. In 1956 the Agr. Engineer. José Krall began what would be called “the Arboretum” in the EEBR with the introduction of forest species from different parts of the world as the first step in the beginning of the first forest genetic improvement programs in the country, as well as practice areas for the training of the students of that time. The objective of this work was to analyze the botanical composition, diversity and behavior of the species that currently make up the Arboretum, by carrying out a total georeferenced inventory. With the data obtained, richness and abundance were analyzed for different taxonomic levels, the silvicultural regime and the natural geographical distribution. In addition, diameter growth parameters were calculated and sampling was carried out to measure the total height of some species in order to obtain hypsometric models for height analysis. Between 2021 and 2022, 51 species distributed in 23 genders were recorded, as well as seven non-cultivated native species. Regarding the growth of the species, the DAP and H_tUsing hypsometric models, they showed similarity with the bibliography consulted. The most abundant species come from geographical regions with climatic conditions similar to those of our country, mainly some regions of Oceania, North America and South America. Currently, the Arboretum represents part of the forestry history of Uruguay, although although it does not have a program to monitor the potential of the materials grown there, it continues to be used for educational purposes for numerous generations of forestry students from the Faculty of Agronomy. This work attempts to make known the value of the Arboretum, both in a botanical, educational, historical, environmental, social and economic sense.

Fertilización nitrogenada en el cultivo de papa

Jonatan Nicolás Núñez Lefebre — 2024-01-26

The potato is one of the most important crops in terms of human nutrition. In our country it is carried out in two cycles a year, determined by weather conditions. One of the factors with the greatest impact on the length of the cycle is nitrogen fertilization. A high nitrogen supply favors the development of foliage and extends the duration of all crop’s phases. In this trial, different doses of nitrogen were evaluated in two genetic materials. Three complete random blocks were carried out in which the treatments were randomly distributed. They consisted of two genetic materials, Arequita and Red Magic, and four doses of nitrogen: 0, 70, 140 and 210 kilograms per hectare. From the combination of both factors, eight treatments emerge. Four samplings were carried out throughout the crop cycle. Variables related to the growth and development of the plants, and the nitrogen content in the different organs were evaluated. At the end of the cycle, the tuber yield was determined and different efficiency indicators were calculated. Leaf area was strongly conditioned by nutrition, being greater with high doses of the nutrient. However, tuberization was only affected by genetic materials, being higher in Arequita. Nitrogen absorption was conditioned by the nitrogen dose. Arequita demonstrating a very high capacity to absorb large amounts of nitrogen in all conditions. The national cultivar, in addition, presented the highest yields, although the high doses affected the commercial quality of the product, increasing the caliber of the tubers. Red Magic had considerably lower yields and was not able to respond to high fertilization. Although nitrogen affected leaf area, no effect on tuberization was observed. In all cases, a very low accumulation of dry matter was achieved in the tubers. This suggests that there are other imbalances that limit the crop's ability to achieve maximum yield. Arequita proved to be a material capable of adapting to a greater diversity of nutritional environments, achieving great efficiency in treatments without added nutrients and being able to respond to very high doses of fertilization. The behavior of Red Magic suggests that it is a material that requires very tight fertilization management, presenting a limited capacity to absorb nutrients available in the soil and optimal performance with medium doses of fertilization.

Optimización fenológica para la producción de semillas de Paspalum dilatatum

Carlos María González Echeverría — 2024-01-24

In the various agro-ecological regions of Uruguay, there is a notable variability in the production of fodder, conditioned by the prevailing soil and climatic conditions. Among the alternatives considered to alleviate the seasonal scarcity of fodder in such scenarios, the incorporation of perennial cultivated species with a summer cycle and C4 metabolism stands out. Within the set of native species preponderant in the Grasslands of the Río de la Plata, the grass Paspalum dilatatum stands out. This species stands out for its remarkable productive capacity and its ability to adapt to various conditions. Currently, these are imported from Australia, where there are favorable climatic conditions and a greater mastery of seed production techniques. Although the material is native to Uruguay, adapted to our conditions, the limited knowledge about the reproductive morphophysiology of these plants leads to seed yields that are economically unviable. This difficulty in the production of national seed is attributed to a common characteristic in grasses, which is the constant emission of panejas, i.e., the reproductive stage coincides with the vegetative phase. Based on the characterization of the flowering curve, the present work was carried out in order to determine the stage of maximum seed production of Paspalum dilatatum. The objective was to evaluate the effect of the phenologically adjusted harvest date on the volume and quality of seeds produced. This work was carried out based on an experimental design using randomized blocks with 3 replicates, where five genotypes of Paspalum dilatatum were used. The data collection consisted of fixing the zero moment for each plot, by counting live plants, fully developed inflorescences, partially developed and those that are still stuffed; the count was carried out on a weekly basis. Two harvests were carried out from November 2019 to January 2020, and from February 2020 to May 2020. In order to be able to compare the two batches of seed production; It was possible to determine that batch one was superior to batch two for the variables studied. Accepting the hypothesis that, yes, there is an optimal time for the production of Paspalum dilatatum seeds.

Evaluación del grano de arroz con cáscara como ingrediente de raciones de recría para vacunos manejados en confinamiento

Santiago Ulery Abilleira — 2023-12-29

The experiment was conducted at the Intensive Meat Production Unit (UPIC) of the Mario A. Cassinoni Experimental Station (EEMAC) in Paysandú, Uruguay, from July 16, 2023, to September 26, 2023. The main objective was to characterize the nutritional value of Rice Husk Grain (GACC) as an ingredient in the rearing rations used in feedlots. This involved describing growth curves, quantifying live weight gain, characterizing dry matter intake, and measuring the effect on digestibility and feed conversion efficiency. Thirty-two Hereford heifers, with an average weight of 272 kg ± 26 kg, born in the spring of 2021 and weaned early in the feedlot, were used. The animals were housed in 32 individual open-air pens and were randomly assigned to four completely mixed rations (RTM) without long fiber, differing in the inclusion level of GACC in substitution for GS, (0% GACC and 45% GS), (15% GACC and 30% GS), (30% GACC and 15% GS), and (45% GACC and 0% GS), expressed on a dry matter basis. The substitution of sorghum grain with GACC in heifer diets did not generate significant changes in intake, weight gain, or feed conversion efficiency. Despite observed differences in digestibility, these did not influence intake, suggesting the presence of intrinsic factors explaining conversion efficiency in different treatments.

Evaluación del grano de arroz con cáscara como suplemento para terneras Hereford pastoreando raigrás Bill Max durante invierno en sustitución del grano de sorgo

Josefina Carrau de Loy — 2023-12-27

The objective of this work was to evaluate the substitution of sorghum grain with rice grain with husk (RGWH) on winter supplementation response in calves grazing Ryegrass. The experiment was conducted in paddock number 6 of the Intensive Meat Production Unit (UPIC) located at the Experimental Station "Dr. Mario Alberto Cassinoni" (EEMAC) Faculty of Agronomy, Paysandú; Uruguay. Thirty-six Hereford heifers born in the spring of 2021, belonging to the experimental herd of EEMAC (140 kg ± 13.3 kg), were assigned to 9 groups, and these to 1 of 3 treatments: exclusive grazing of Bill Max ryegrass at a forage allocation (FA) of 2.5% of live weight without supplementation, or supplemented with sorghum grain or rice grain with husk. Grazing was carried out in 7-day occupation plots, adjusting the FA of each plot weekly based on the availability of ryegrass dry matter and the average weight of the animals in each plot. The supplement was provided daily in the morning at a rate of 1 kg/100 kg LW (dry basis). The experiment was analyzed using a randomized block design with repeated measures over time. When the treatment effect was significant, means were compared using orthogonal contrasts, evaluating the effect of supplementation and the effect of the type of supplement. Supplementation improved daily live weight gain (58 vs. 289 g/day, P<0.01), with higher ADG in the sorghum-supplemented treatment than in the RGWH-supplemented treatment (312 vs. 266 g/day, P<0.05), with a conversion efficiency of 6.5 and 7.78, respectively. The total dry matter intake of supplemented animals was 61.8% higher than non-supplemented animals, with no statistical differences in forage and supplement intake between the different treatments. Finally, it was observed that control animals tended to increase grazing activity, although there were no significant differences between treatments for both grazing and rumination. In the case of bite and rest rate, animals supplemented with RGWH showed higher activity. In conclusion, winter supplementation improves ADG in heifers grazing Bill Max ryegrass at a FA of 2.5% LW. This response will be greater when using sorghum grain compared to RGWH.

Desempeño reproductivo de vacas de 1er parto de las razas Angus, Braford, Brangus y Hereford

Gerónimo Otegui Ham — 2023-12-22

The purpose of this study is to evaluate the reproductive performance of first-calving cows from Angus, Braford, Brangus, and Hereford breeds. These cows were served for the first time at 18 months of age, preceding the second breeding season under natural grazing conditions. The research took place at 'La Magdalena' farm, owned by Los Tordos SA, situated 17 km away from km. 53 of route no. 31, in the 9th Police Section of the Salto department in Uruguay. The experimental period spanned from days before the first births in March, extending until October, just before the spring service. A total of 77 cows were managed under consistent environmental and management conditions, comprising 25 Angus, 16 Braford, 14 Brangus, and 22 Hereford. Three key variables were recorded: live weight, body condition, and ovarian activity—the determinant of reproductive performance, assessed at three strategic moments. Live weight and body condition were recorded six times to complement reproductive information. The experiment concluded with the final diagnostic of ovarian activity before a new fixed-time artificial insemination protocol. Variance analysis revealed no significant differences in reproductive performance among the studied breeds in this work.

Producción de leche en vacas primíparas y crecimiento de los terneros en las razas Angus, Braford, Brangus y Hereford en pastoreo

Ramon Juan Sarries Liendo — 2023-12-22

The aim of the study was to evaluate milk production and composition and its effect on calf growth for Angus, Brangus, Braford and Hereford breeds. The work was carried out at the Estancia "La Magdalena" belonging to the firm "Los Tordos SA", located in the department of Salto - Uruguay.

The field survey was carried out from March 2023 until the end of August of the same year and it is important to point out that all the animals were under the same conditions during the experiment.

We used 24 primiparous cows born in the spring of 2020 of the following breeds: Aberdeen Angus, Hereford, Brangus and Braford. We worked with a sample of 6 animals per genotype, with their corresponding calves of the same breed.

As far as feeding is concerned, the animals were kept on natural pasture throughout the experiment. The farm is located on soils of relatively high natural fertility.

From calving to final weaning, the milk production of the 24 primiparous cows and the weight of the calves were measured monthly.

The results obtained show that there were no significant differences in milk production and milk composition between the breeds evaluated. Calf growth was also not significant according to breed.

Efecto del fuego en la dinámica de malezas y comportamiento de herbicidas premergentes en Eucalipto

Lucía Airaudo Gardil — 2023-12-22

The forest fires that occurred during summer 2021-2022 in Uruguay generated concern in several areas, including silvicultural systems. The fire could generate changes at the flora level by changes in the dormancy of soil bank seeds, and in the behavior of frequently used preemergent herbicides due to inactivation by ashes. These possible changes impose a challenge in connection to weed control. In this study, an attempt was made to provide an answer to the problem by evaluating the dynamics of weeds and the behavior of preemergent herbicides in post-fire Eucalyptus plantations. The evaluations were carried out in two sites previously burned, one of them previously harvested and the other one not, being able to obtain data in different conditions. The weed dynamics was evaluated through the observational study of the percentage of total weed cover and present species were identified in a square 30cm×30cm. With the data obtained, the parameters frequency, diversity and richness were calculated to analyze the different properties separately. Preemergent herbicides were evaluated in a randomized block experimental design. Proposed treatments were: S-metolachlor, flumioxazin + S-metolachlor, isoxaflutole + S-metolachlor, oxifluorfen + S-metolachlor. It were assessed for possible interactions with fire and removal of the first cm of soil and ashes. Weed density was evaluated by characterizing and quantifying how many weeds could emerge in a square 30cm×30cm. On both experiments the fire showed an increase in the weeds. In one experiment the weeding percentage increment was 64.9% to 54.3 %. In addition, in the non-harvested field there were no large amounts of weeds on both treatments due to the conditions that standing trees generated. The results of weed control did not show interaction between efficiency and ashes presence, and were related to the species present in the weed bank, not showing a clear trend among the herbicide treatments. The number of weed/m² was about 17-25 on the harvested field, and 3-4 weed|m2 on the non-harvested one. The fire generated changes in the expression at seed bank of soil. This study was an important deve202ment in the generation of knowledge for future production.

Comportamiento de amamantamiento de terneros en las razas Angus, Hereford, Brangus y Braford.

Luis Pedro Ponce de Leon Andregnette — 2023-12-22

The objective of the study was to determine the suckling behavior and growth of calves from the Angus, Hereford, Brangus, and Braford breeds. The research was conducted at Estancia La Magdalena, owned by "Los Tordos SA," located 17 km from kilometer 52 of route 31 in the 12th Police Section of the Department of Salto, Uruguay.

The survey was carried out from March 2023 until the end of August of the same year. It's worth noting that the animals were kept under the same conditions throughout the experiment. A total of 24 cows and 24 calves were used for the study; the mothers were primiparous, born in the spring of 2020. The sample consisted of 6 pairs of mother and calf for each breed, including 3 male and 3 female calves.

Regarding feeding, the animals grazed on natural pasture throughout the experiment. The land of the establishment is relatively high in natural fertility.

From birth to weaning, monthly observations were conducted throughout the day to monitor the activities of the calves, including suckling, resting and grazing. A total of 5 observations were made. The results indicate that there are no significant differences in suckling, resting and grazing behaviors among calves of the different breeds evaluated.

Rol de las mujeres en la producción familiar

Antonela Figarola Sum — 2023-12-21

The social invisibility of the role of women, product of the conditions of inequality and dominance over the female population, is a phenomenon that translates, at the rural level, into ignorance of the role that women play in the national agricultural production. The phenomenon is linked to patriarchy and the sexual division of labor, which tends to relate men to the sphere of production and money (considered superior) and to grant women the domestic and reproductive place. To contribute to the understanding of the role of women in family production and make their contributions visible, some research from the qualitative paradigm was used. Its objectives were to comparatively analyze three cases of family producers linked to colonies from the Uruguayan coast, which made it possible to identify and describe female strategies of resistance present in the cases. For this, semi-structured interviews were carried out, which allowed the construction and validation of biographical trajectories. These were analyzed according to the origin and beginning of women as producers, their consolidation and integration into organizations and collective actions. The comparative analysis of the cases generated results about access to the land and the female economic succession and symbolic strategies present in them. The results indicate that women, in addition to contributing with their productive and reproductive job to maintain the autonomy and economic independence of families, develop economic strategies for the valorization of production and its commercialization, which allows them to manage their own money. These economic strategies are also connected to children’s raising and the development of farm succession strategies. Within rural organizations, exchanges of work, knowledge, and tools between neighbors, peer groups, or collective ventures stand out, as well as state projects and programmers.

Caracterización de los productores del litoral sur del país en función de la adopción e implementación de cultivos de servicio

Emanuel González Alvarez — 2023-12-20

Agricultural expansion in Uruguay from the beginning of the 21st century to the present has carried to accelerated soil degradation, causing losses due to erosion, explained by a scheme based on continuous agriculture, monoculture systems, and intensification of agricultural practices. With the aim of regulating this problem, in 2013 the Ministerio de Ganadería, Agricultura y Pesca (MGAP) launched the Responsible Land Use and Management Plans. The mandatory nature of the regulations materialized in the inclusion of service crops in agricultural rotations. This work aims to characterize the producers of the southern region and western coast of Uruguay in terms of adoption and implementation of service crops. Surveys were conducted with producers and technicians, collecting data on experiences, perceptions and practices related to service crops. The results revealed that the majority of producers/technicians have a positive view of the benefits of including service crops in their agricultural rotation, highlighting their importance in soil conservation, weed control and carbon contribution. Producers who use the technology are characterized by using pure grasses as the main species, especially white oats, black oats and ryegrass; that are planted post-harvest with a seeder and are finished with chemical control. There is a tendency not to graze the service crops, which reflects that agricultural activity is not integrated into livestock systems. Technical decisions are made independently of the type of land tenure and the geographic area where the fields are located. The main difficulty for its widespread adoption is related to the cost or necessary investment, because it does not generate short-term economic benefits. Although the mandatory nature of the regulations has led to raising awareness about the sustainability of soil resources, the generation and dissemination of information linked to the use and management of service crops in agricultural systems is still necessary.

Evaluación de la germinación de semillas y el vigor de plántulas de genotipos nacionales de arroz en condiciones de frío

Fabián Leandro Makowski Bozzolasco — 2023-12-19

Rice holds a prominent position among the most relevant crops in our country, and it stands out as a significant producer and trader on a global scale. However, the crop faces significant challenges due to climatic conditions, especially low temperatures at the planting date, directly impacting crop yield. This research focuses on characterizing germinative response and plantlet vigor in cold temperatures for several national rice genotypes from different subspecies and subtypes. The aim is to identify the most promising genotype that would allow planting in low-temperature conditions, enabling an earlier start to the crop cycle to achieve higher yields. Several trials using freshly harvested (one month after harvest) and after-ripened (four months after harvest) seeds were conducted to measure and compare seed viability and germinability, and plantlet vigor at two temperatures: 25 (optimum) and 15 °C (cold). As expected, differences in germination between temperatures were observed because of the expression of seed dormancy in cold conditions, which decreased after four months of dry storage. Germinative responses and plantlet vigor at low temperatures conditions were influenced by origin (defined by subspecies and subtype), where temperate japonica genotypes showed a more favorable response to cold conditions. No differences at the origin level between the tropical japonica subtype and the indica subspecies were observed, although there were differences at the genotype level within these groups. Genotype SLI 17158 exhibited the most noteworthy germinative and plantlet performance in cold, making it an attractive plant material for future breeding programs.

Calidad nutricional del polen de colza (Brassica napus) y determinación de la flora apícola acompañante para las abejas melíferas

Sofía De León Guedes — 2023-12-18

Rapeseed (Brassica napus L.), a winter oilseed, holds agricultural and apicultural significance due to its contribution of pollen and nectar at the end of winter. Pollination enhances crop yield and quality, as well as promotes uniformity in pod formation and maturation. It is crucial to understand the relationship between honeybees and rapeseed flowering. In a study conducted in Sauce, Canelones, and Arrayanes, Maldonado, the resources utilized by Apis mellifera L. from the crop to feed three randomly selected hives in each apiary were analyzed. Pollen and honey collected during flowering were investigated using palynological techniques. Precipitation during the crop cycle was considerably below the historical average. Key results include: a) In addition to rapeseed pollen, bees collected from eighteen additional plant species, in proportions higher than expected. b) Rapeseed pollen was a significant food source despite the water deficit. Hives showed variability in the timing of peak rapeseed utilization, indicating different preferences despite the same floral offer. c) Particularly, low levels of crude protein and ether extract were found, similar to those reported in semi-arid conditions. d) Mineral levels were low for magnesium but high for calcium, iron, and especially zinc, with values three times higher than reported. e) Honey from a single hive was predominantly rapeseed (>60%), with a significant contribution from perennial plants. f) No traces of glyphosate or AMPA were detected in samples taken 100 days after application. g) While no hive showed a prominent preference for rapeseed, differences were observed between hives and apiaries. h) Bees visit the crop more as flowering progresses and lipid content increases. i) Positive correlations were found between various quality parameters. The research highlights the importance of understanding bee feeding preferences to ensure the proper development of hives and anticipate contingencies due to climatic anomalies. Bees are recognized as valuable pollinators of rapeseed.

Efecto del grupo genético y la oferta de forraje sobre la respuesta productiva de vacas de cría en campo natural

Laura Méndez Olivera — 2023-12-05

The objective of this study was to evaluate the interaction between forage allowance (FA) (9 and 6 kg DM/ kg LW annual average for high (H) and low (L) FA respectively that vary seasonally) and crossbreeding (Hereford and Angus purebreds (P) and F1 crosses (C)) on forage mass, stocking rate, body condition score (BCS) and live weight (LW) of the cow, LW of the calf, ovarian activity (follicle size, presence of corpus luteum), and total pregnancy in a production cycle (start in autumn/second trimester of gestation at the end of summer/final weaning at 147 days pospartum (dpp)). Thirty-five pregnant multiparous cows were used in a randomized block design with a factorial arrangement of two FA treatments and the crossbreed. Suckling restriction (SR) and flushing (Fl) were applied at the beginning of calving (52 dpp). Forage mass, BCS and LW were determined monthly and FA was adjusted using the put and take method (Mott and Lucas, 1952). Ovarian activity was recorded before suckling restriction and flushing (Fl), during Fl and post Fl. Total pregnancy was evaluated by ultrasound at 147 dpp. H had higher mass forage than L (2064 and 1368 ± 234 kg DM/ha; p <0.05). Low precipitation levels would have restricted forage growth and resulted in lower levels of forage mass and stocking rate than expected mainly in L. H improved BCS during the fall (4.3 and 4.0 ± 0.12 kg DM/ha; p<0.05) and follicle size (11.8 and 8.16 ± 0.79 mm; p<0.01) relative to L. C cows had higher BCS from -131 to -94 dpp (p<0.05) and from -24 to 140 dpp (p<0.05), larger follicle size (10.77 vs 8.55 ± 0.77 mm; p=0.06) and tended to have higher final pregnancy than P cows (85 vs 48 ± 12%, p=0.1). Calves from P cows on L had less weight than the other treatments at weaning (163 vs. 173 ± 6.8 kg, p<0.05). H forage allowance positively affected BCS, follicle size and calf weight at weaning of P cows while C cows had higher BCS, follicle size, higher pregnancy and calf weight at weaning on L compared to P.

Determinación del daño potencial de Tupiocoris Cucurbitaceus (Spinola 1852) (Hemiptera: Miridae: Dicyphini) en Solanum Lycopersicum

Gastón Pardo Doldán — 2023-12-04

Mirids are zoophytophagous predators widely used and studied in biological control programs in Europe. In Latin America, Tupiocoris cucurbitaceus is a naturally present species and has several characteristics that give it good potential as a biological control agent. It has the ability to control several pests of tomato crops such as whitefly eggs and nymphs, T. absoluta eggs, and T. urticae adults, among others. It has a wide range of plant hosts, phytophagy allows them to remain in the system during short periods of prey scarcity, they have high fertility and their cycle is relatively fast. Predation represents their main form of feeding and obtaining nutrients, although phytophagy also occurs in a rare and complementary way. Therefore, the objective was to find out if there is damage and loss of yield in the tomato crop caused by T. cucurbitaceus due to the scarcity of prey, conditioning its feeding to the phytophagy; thus, evaluating the potential risk on the optimal development of the tomato crop. To do this, different densities of T. cucurbitaceus were released in experimental cages with tomato plants and in the absence of prey. The results showed that their establishment and permanence in the system is directly related to the abundance of prey, therefore, phytophagy allows them to survive for short periods of time, but they are unable to complete their development without the occurrence of predation. The lesions observed by phytophagy occurred on leaflets and were characterized as scores less than 1mm, rounded and brown to black in color. The number of scores was never greater than 3 per tomato leaflet and its incidence is directly related to the population level of the mirid. No significant effect was observed for the different variables measured in vegetative and reproductive organs for any treatment evaluated.

Efectos de la fecha de siembra sobre el rendimiento de soja en condiciones de riego y secano

Lucas José Lafluf Heguaburu — 2023-11-30

In the 2021-2022 crop year, a trial was conducted to evaluate the effect of sowing date on a soybean cultivar (Glycine max, L.) with a V short maturity group, which presents a high yield potential under irrigated and rainfed conditions. The trial was done at the Experimental Station “Dr. Mario A. Cassinoni” (EEMAC), Faculty of Agronomy, in Paysandú, Uruguay. The evaluation consisted of three sowing dates, October 9, November 10 and December 11, each under irrigated and rainfed conditions. It was carried out in a design of complete random blocks in divided plots, where the three sowing dates were the major plots, while the water availability (irrigated and rainfed) were considered as minor plots, which were randomly arranged in the major plot. Irrigation management was carried out with a watering threshold of 60% of available water during the critical period and 40% of available water in the non-critical stages, thus maintaining the crop under water welfare conditions. Four replications were carried out with six treatments in each, distributed in 24 experimental units. Irrigated yields were higher than in rainfed treatments at each sowing date. Under irrigation the December sowing date yielded 5016 kg ha-1, followed by the November sowing date with 4701 kg ha-1 and finally the October sowing date with 4277 kg ha-1, there were differences between the December and October sowing date. There were no differences in the number of grains per square meter, but the grain weight did differ, with the December sowing date having the highest value, followed by November and finally October, part of which explains the differences in yield. The high average and maximum temperatures to which the early sowing date were subjected, added to the effect of solar radiation, which was lower during the critical period, meant that the early sowing date could not express their potential. Both the October and November sowing date transformed less efficiently the dry matter production to grain production, being December the most outstanding in this point. In rainfed conditions, the December sowing date stood out over the other sowing dates, this performance is mainly explained by water availability and by the escape to the high atmospheric demands in the critical period. In conclusion, the early sowing dates placed the critical period in more favorable situations to obtain higher yields; however, the year presented solar radiation levels and temperatures that negatively affect the achievement of yield.

Propuesta de proyecto hortícola agroecológico en predio manejado por jóvenes colonos en Canelones, Uruguay

Natalia da Rosa Correa — 2023-11-24

“Germina” is a group of youngsters who carry out an agroecological project in Canelones on a farm owned by the National Institution of Colonization. The project combines agriculture, livestock and vegetable production. The objective of the work was to design an agroecological vegetable project, developing a productive plan for horticulture. The development of the project was carried out in three stages: characterization of resources, definition of objectives and plan development, and ultimately, productive, socioeconomic and environmental evaluation. During the characterization of resources, the soil was characterized through the analysis of secondary information (geological map and soil map of Uruguay), the survey of soil profiles and their chemical analysis. Based on this, different soil units were defined and the soil suitability map was created. The vegetation was characterized by the observation and recording of the general state of the field. Then different types of vegetation were identified and a vegetation map of the farm was drawn. Available water sources, available labor and infrastructure were identified. In the second stage, the objectives of the project were set: to design a suitable crop rotation with agroecological bases that enables marketing in nearby cities, adding up to the income of the members of the group. The crops, the rotation plan, the general management, and the associated costs were defined based on the available resources. A soil organic carbon balance was carried out to define the incorporation of compost. In the third and final stage the project was evaluated through nutrient balance (environmental evaluation), marketable crop yield and marketing moments (productive evaluation), gross product and margins, cost structure and total income and per hour of work and requirements of work throughout the year (socioeconomic evaluation). The outcome of the evaluation shows that it is possible to carry out an agroecological vegetable production project that will generate added income for the members of the group.

Herencia de la pigmentación ocular en el rodeo Hereford de la Estación Experimental Mario A. Cassinoni

Lucía Clerici Young — 2023-11-16

Ocular pigmentation in cattle is related to the presence of melanin pigment in the periocular region. It has photoprotective properties, which is why it has been of interest. The relationship between the degree of ocular pigmentation and the incidence of diseases has been studied. In turn, this characteristic is heritable so, through genetic selection, the degree of pigmentation can be increased, thus reducing the incidence of diseases. The present work, carried out in May 2023, consists of a characterization of the ocular pigmentation of the Hereford breeding herd of the Mario A. Cassinoni Experimental Station, Faculty of Agronomy, University of the Republic. A total of 51 calves born in 2022 and 51 breeding cows were sampled using the scale proposed by the Uruguayan Hereford Breeders Society: from 0 to 100%, with 25% intervals. The calf population had an overall average eye pigmentation, both eyes, of 90%, while that of the dams was 77%. Insemination was performed with 100% pigmented bulls, in order to achieve rapid genetic progress in favor of pigmentation. Eighty-two percent of the calves sampled had 100% average pigmentation of both eyes, while 61% of the cows had 100% eye pigmentation. The relationship between average eye pigmentation of parents and offspring was studied through a second degree polynomial function: y= -0.0297 x2+6.1369 x - 215, 98, adjusted with an r2 of 0.9534. That is to say that for every 25% increase in the ocular pigmentation of the parents, the offspring increase by 6.13%, stagnating at values close to 80-90%.

Estudio de la zarzamora (Rubus ulmifolius Schott) como leñosa invasora de bosques nativos en Uruguay

Belén De Cuba Perazza — 2023-11-15

Invasive alien species (IAS) constitute a serious global environmental problem. Rubus ulmifolius (blackberry), has been reported as an IAS in our country, given that it quickly colonizes forest ecosystems, displacing native species, and generating various impacts. Despite its invasive potential, there is no history of studying blackberry in Uruguay. The general objective of this study was to study the invasion by blackberry in a riverine forest within the protected area “Wetlands of Santa Lucía”. The specific objectives were (i) to describe the degree of invasion of the forest by blackberry, evaluating its abundance and coverage under three levels of disturbance: native zone, altered zone and logged zone; (ii) study the community of shrubs and tree regenerants to evaluate the impact of blackberry on these communities, and (iii) study the relationship between the invasion of blackberry (density and coverage) and the incidence of light. The study area was a riparian forest of the San José River, in which an 80 m wide strip was cut down in 2022 for the installation of a UTE High Voltage line. In autumn 2023, 10 plots (4 m²) were randomly sampled in each area, in which data on: abundance of regenerants , species in the canopy and soil cover were collected. Then the diversity index was calculated by zone and compared between zones: density of total regenerants , density and cover of blackberry and soil cover categories. Finally, the relationship between the density and coverage of blackberry and the PAR (photosynthetically active radiation) transmitted was evaluated. The species under study presented variations in its abundance and coverage associated with the disturbance gradient. Significant differences were found in the abundance of blackberry between the three areas evaluated. Likewise, it was observed that blackberry is the dominant exotic species. The sampling area that presented the greatest diversity of total and native species was the native area followed by the altered and logged area. A positive and significant relationship was found between blackberry abundance and light incidence, which reinforces the idea that changes in canopy structure are strongly involved with the degree of blackberry invasion. In the native area there is less incidence of light in the understory, given that the canopy structure is more closed, which strongly limits the abundance of blackberry. In the three areas studied, the most abundant species within the woody regenerating community was an IAS, this is highly worrying, taking into account that it is a riparian forest within a protected area of the SNAP (National System of Protected Areas). The present study shows the effect of anthropogenic degradation, in this case due to deforestation and IAS, on the diversity and structure of native forests and highlights the importance of adequate management of ecosystems within protected areas.

Ajuste de modelos para la estimación de biomasa y carbono en plantaciones de Eucalyptus dunnii

Matias Mañana Diz — 2023-11-15

The commercial plantations of Eucalyptus dunnii has increased in surface through all the national territory, which was promoted by the raise in the demand of the raw material for pulp production. These plantations are characterized by high primary productivity, accumulating biomass and promoting carbon sequester. Nonetheless, the direct quantification of biomass and carbon stocks presents limitations due to the high operational effort and time needed. The adjustment of predictive models is an efficient form for obtaining relevant information for the sustainable management of forest plantations. This study aims to obtain models for estimating biomass and to quantify the carbon stock, in populations of E. dunnii at ages of 3 and 7 years old on soils CONEAT 2. Based on these characteristics 4 stratums were defined, in which 48 forest inventory plots were measured, distributed in equal number among the stratums. The data obtained was used for selecting 58 trees for destructive evaluation, sectioning the aerial biomass in stem (SB), thick branches (TcB), thin branches (TnB), leaves (LB) and total (TB). Initially, independent nonlinear regression models were fitted for fractions and total biomass, considering both ages separately. The models selected were finally adjusted in simultaneous for obtaining additive models for the fractions through the process of nonlinear seemingly unrelated regression (NSUR). The quantification of carbon stocks from populations were realized using the aerial biomass estimated, and carbon concentrations obtained with individual fractions samples. The results presented the following order of models fit quality for the biomass variables: TB > SB > TcB > LB > TnB. The models of SB and TB presented high predictive capacity, with R² adjusted superior to 95%. The models of TcB, TnB and LB presented higher variability in the estimates compared to those of SB and TB, nonetheless, the obtained values of R² adjusted were over 70%. Regarding the forest productivity, the values verified were similar among the stratums of 3 years old plantations and presented greater difference at those of 7 years, what can be associated to the site quality and competition among trees. The total biomass stock for populations of 3 and 7 years old were 65.93 y 119.51 Mg ha^-1, respectively. Respect to the fractions of TcB, TnB and LB, the population of 3 years presented superior absolute and relative values respect to those of 7 years, indicating a raise in stem biomass assignation and crown reduction at older ages. The results obtained show an efficient and precise estimation of forest biomass, and the productivity levels verified indicate a high potential for carbon sequestration with E. dunnii forest plantations.

Estimación de consumo de forraje mediante métodos indirectos para situaciones de altura residual contrastantes

Nicolás Cros Méndez — 2023-11-14

A study was carried out at the Southern Regional Center (SRC) of the Faculty of Agronomy with the objectives of estimating the direct consumption of forage of dairy cows for two contrasting grazing managements using indirect methods, and comparing the methods used. The study was carried out during the spring of 2019, from September to December. Two grazing intensities were applied: intense management (A) of 4 cm and lax management (B) of 9 cm. For the determinations, two indirect methods were used, the C-Dax and the Measuring Plate, and the Double Sampling method was used as a reference. Four batches of 24 animals of the Holando, Jersey breeds and their crosses, calved in autumn, grouped by weight, body condition and number of lactations, were used. The forage base was composed of perennial pastures made up of Dactylis Glomerata and Trifolium Repens and winter greens made up of Lolium Multiflorum and Avena Byzantina. The pasture entry criterion was when the Dactylis reached the state of three fully expanded leaves. In addition to the forage, the animals were fed with reserves and concentrate. Two milkings were carried out per day (05:00 and 15:00), and grazing was carried out in daily strips, with a double shift of access to the pasture when the growth rate and forage stock allowed it, otherwise, they grazed in turn, remaining penned up after the second milking with the supply of reserves and water at will. The determinations were made three times a week, estimating with each indirect method the available forage pre and post grazing of the daily strip and with this information the direct consumption of the animals was calculated. In addition, there was information on the production of milk and solids of each batch that was determined biweekly. A randomized complete block design with factorial arrangement of treatments was used. The animals corresponding to management B had a greater direct consumption of forage with respect to the animals of management A. The C-Dax and the Measuring Plate presented a similar behavior, although they remained below the Double Sampling method in a large part of the period. experimental. Milk production and composition was similar between grazing managements. The results indicate that it would be possible to estimate the direct consumption of animals grazing daily strips with different post-grazing residual forage situations using indirect methods, taking into account the strengths and weaknesses of each one, as well as their requirements and manner of execution. Additional studies would be convenient to obtain more robust results and thus obtain more information about these useful tools for carrying out determinations and monitoring in pastoral production systems.

Dinámica de la asignación forrajera durante el último tercio de gestación y hasta el destete

Bruno Ramírez — 2023-11-10

Uruguay's livestock systems are sustained on a pastoral basis, whose production fluctuates in quantity and quality throughout the year. In this context, late gestation and the beginning of lactation coincide with periods when forage production decreases, which forces pregnant animals to reprogram the intrauterine growth trajectory. The aim of the present work was to study the effect of the dynamic change in forage allocation in the period between the last third of gestation and weaning on productive behavior and metabolism of primiparous cows and their calves, grazing natives pastures. For this, two treatments were used: a) high supply of forage (AOF, last third: decrease from 8 to 4 kg DM / 100 kg LW, calving to weaning: rise from 4 to 12 kg DM / 100 kg LW) and b) low supply of forage (BOF, last third of gestation, was maintained, 4 to 4 kg DM / 100 kg BW, parturition to weaning: rise from 4 to 8 kg DM / 100 kg BW). The trial was carried out at the Bernardo Rosengurtt Experimental Station, Cerro Largo, Uruguay. No treatment effects were observed on maternal metabolites, glucose (3.15 ± 0.06 vs. 3.23 ± 0.07 mmol / L, P = 0.4453), urea (28.43 ± 0.80 vs. 27.44 ± 0.88, total protein (64.11 ± 0.77 vs. 65.68 ± 0.81, P = 0.1756), albumin (30.81 ± 0.39 vs. 31.26 ± 0.41, P = 0.4300) g / L, P = 0.4170), BHB (0.60 ± 0.05 vs. 0.61 ± 0.05, P = 0.7992) mM, AOF vs. BOF, respectively. Neither treatment effects were observed on the calf metabolites, glucose (4.49 ± 0.16 vs. 4.41 ± 0.17, P = 0.7440), urea (21.93 ± 0.71 vs. 20.46 ± 0.79, P = 0.1785), total protein (56.48 ± 0.82 vs. 57.68 ± 0.90, P = 0.3377), alumina (33.02 ± 0.45 vs. 33.90 ± 0.49, P = 0.1966) g / L, AOF vs. BOF, respectively, except immunoglobulins (22.16 ± 0.91 vs. 24.91 ± 1.03, P = 0.0574) g / L and BHB (0.10 ± 0.03 vs. 0.24 ± 0.041, P = 0.0231) m / M, AOF vs. BOF, respectively. The PV of the calves at birth did not show significant differences, however, at weaning, the BOF calves had a PV 10% higher than the AOF calves. The study of the morphological characteristics of the placenta indicated that the BOF placentas had a greater cotyledonary surface. Nutritional restriction during pregnancy did not significantly affect maternal metabolites or their offspring, except for immunoglobulins. This could indicate that the body starts up adaptive metabolic and placental mechanisms in such a way that physiological processes continue under the new prevailing conditions.

Análisis del comportamiento meiótico de híbridos interespecíficos del género Paspalum

Facundo Bassini Trujillo — 2023-11-09

The addition of a summer perennial grass to the pasture mixes presents various advantages, such as productivity, seasonal distribution of forage, and resilience, as well as adaptability to climate change. The Dilatata group of the genus Paspalum contains valuable of these grasses with high agronomic potential. Of these species, the most studied has been Paspalum dilatatum var. dilatatum, a pentaploid with apomictic reproduction. This species, despite its high production of dry matter, presents numerous difficulties for its use, such as: low seed production, infection by Claviceps paspali, seed dormancy and slow implantation, as well as difficulties for its improvement. given its apomictic nature. Therefore, a new approach has been carried out in the Faculty of Agronomy, prioritizing the sexual tetraploids of the group (P. flavescens, P. plurinerve, P. vacarianum, P. dasypleurum and P. urvillei), since they present greater possibilities of domestication, due to its sexual breeding system which facilitates genetic improvement. These sexual species are related, have high fertility, high viable seed production, are autogamous and share the genomic formula 2n = 4x = IIJJ, so hybridization among them should be possible. One breeding strategy is interspecific hybridization seeking to combine the best of each species for the formation of a cultigen. In order to carry out an interspecific hybridization program, it is necessary to prove that the available germplasm can be hybridized without decreasing hybrid fertility. As a direct background to this work, a biparental population of recombinant inbred lines (RILs) was previously generated from the cross of P. flavescens x P. plurinerve (both promising species and similar to the "common" genotype in terms of productivity, in addition to presenting differences in terms of flowering date and seed dormancy) using the SSD (single seed descent) method. This previous aim was to evaluate the potential of this breeding method, looking for transgressive segregation, in addition to genotyping and phenotyping the entire collection to identify QTLs associated with domestication characters, such as reduced dormancy. During these efforts, sterility was found in some early lines and a distortion in the segregation of microsatellite-type molecular markers in the F₆. These phenomena may be associated with irregularities in the meiosis of the hybrid, since although related species, they have differences in their genomes. Therefore, in this work, the meiotic behavior of 20 F₂ lines from the interspecific hybridization of P. flavescens x P. plurinerve was analyzed, as well as the degree of fertility of these lines based on seed production. A minimum of 15 pollen mother cells (PMCs) were recorded for diakinesis, metaphase, anaphase, and dyads/tetrads, seeking to detect associations other than bivalents in diakinesis, chromosome advances in metaphase, bridges or delays of chromosomes in anaphase and micronuclei in dyads/tetrads. The results show that 9,5% of the PMCs studied presented irregularities in meiosis, without observing any micronuclei in dyads/tetrads, so that irregularities in early phases of meiosis end up being resolved in later phases. Seed production of the 20 lines ranged from 0% to 63%, with an average of 28% full seeds. No irregularities in meiosis were found to explain the low fertility of some lines. Therefore, meiosis does not explain the sterility in the early lines reported above, nor the distortion in segregation. Other reasons may explain these phenomena, such as genetic control of sterility, that is, there are genes that cause sterility in interspecific hybrids. Molecular cytogenetic techniques like FISH and molecular markers in F₂ lines can determine at what point in inbreeding the distortion in the markers occurs, in addition to describing, using GISH, the bias towards maternal alleles in the chromosomes of F₆ lines.

Solubilización de fósforo por lupino (L. albus y L. angustifolius) en 4 suelos contrastantes en condiciones de invernáculo

Andrea Bentos Guimaraes Rodriguez — 2023-11-09

A substantial amount of phosphorus (P) in soil is not readily available for plant uptake. Certain species may enhance P availability from poorly soluble P forms. The objectives of this greenhouse essay were as follows: i) to assess soil P availability (PBray1) by comparing two Lupine species, L. albus, and L. angustifolius, with a control crop of oats (Avena strigosa L.), ii) to evaluate accessible P levels and soil pH in four soil types with lupine to oat-containing soil and their baseline values. iii) to investigate how plant species and soil type affect shoot biomass, biological nitrogen fixation (BNF) rate, and potential P and nitrogen (N) contributions of two lupine species as precursor crops. Plants were cultivated in pots in four soils with varying textures, organic matter content, acidity and P availability. At harvest, various parameters were assessed, including shoot dry weight, plant P and N content, as well as lupine nitrogen fixation. Lupine soils showed PBray1 concentrations from 0.9 to 5.4 mg kg-1 (p < 0.0001), depending on species, sampling time, and soil type, when compared to soils containing oats. Interestingly, lupine-induced soil acidification did not fully explain this P increase. Manganese (Mn) concentration, an indirect measurement of organic acid exudation, was high in both lupine species' shoot biomass; however, these legumes had divergent responses to soil acidity and P availability. Nitrogen fixed quantity varied by Lupine species (105-240 mg pot-1) and soil type (60-240 mg pot-1). Lupinus albus had higher ability to mobilize non-labile P and give N through BNF, positioning it as a suitable crop for diversifying Uruguay's agricultural crop rotation systems.

Manejo de la carga en manzanos `Early Red One´ y `Rosy Glow´

Fernando Armesto Corujo — 2023-11-01

Apple trees set more fruit than desired, thus it is necessary to adjust the crop load to achieve a better fruit size and an adequate return bloom, thereby avoiding biennial bearing. The objective of this thesis was to evaluate different chemical products with a thinning effect. Applications were made of: calcium polysulfide (calcium sulfide mixture/sulfocalcic mixture), Metamitron, naphthaleneacetic acid (NAA), and 6-benzyladenine (6-BA). Two trials were conducted in the province of Canelones, Uruguay, during the 2021/2022 season on two apple cultivars: 'Early Red One' and 'Rosy Glow'. In 'Early Red One' apple, five treatments were evaluated: 1) trees without application (control); 2) calcium polysulfide at 3% concentration (2 applications, 60% of open flowers and four days later); 3) 100 mg L^-1 Metamitron applied between 8-12 mm of the fruit; 4) 200 mg L^-1 Metamitron applied between 8-12 mm of the fruit; and 5) NAA at 10 mg L^-1 at full bloom along with NAA at 7.5 mg L^-1 + 6-BA at 100 mg L^-1 at petal fall. In 'Rosy Glow' apples, five treatments were also evaluated: 1) trees without application (control); 2) calcium polysulfide at 3% concentration (3 applications, 80% of open flowers, two and five days after the first application); 3) 200 mg L^-1 Metamitron applied between 8-12 mm of the fruit; 4) 400 mg L^-1 Metamitron applied between 8-12 mm of the fruit; and 5) NAA at 10 mg L^-1 at full bloom along with NAA at 10 mg L^-1 + 6-BA at 100 mg L^-1 at petal fall. In all treatments, manual thinning was carried out around 50 days after full bloom. The following parameters were evaluated: percentage of fruit set, amount of thinned fruit, time spent in crop load adjustment (manual thinning), number of fruits per plant, average fruit weight, yield per plant, estimated yield, yield efficiency, fruit diameter and height, height/diameter ratio (constructed variable), percentage of red color in the fruit, russeting, penetration resistance (flesh firmness), starch index, total soluble solids, and number of seeds. The efficiency ranking of the treatments varied according to the cultivar. In 'Early Red One', the most efficient treatment was the application of NAA at full bloom along with NAA + 6-BA at petal fall, and in 'Rosy Glow', it was the application of 400 mg L^-1 Metamitron. The shortest thinning time required to adjust the load was observed in the NAA treatments at full bloom together with NAA + 6-BA at petal fall and 400 mg L^-1 Metamitron ('Early Red One' and 'Rosy Glow' cultivars respectively). In 'Early Red One', no differences in fruit size were observed between treatments. In 'Rosy Glow', the treatments that presented larger fruit diameter were: 3% calcium sulfide mixture/sulfocalcic mixture applied at 80% of open flower, 200 mg L^-1 Metamitron at 8-12mm, and NAA at 10 mg L^-1 at full bloom + NAA 10 mg L^-1 + 6-BA 100 mg L^-1 at petal fall. In 'Early Red One' estimated yield was not affected in any of the treatments compared to the control, but in 'Rosy Glow', there was a difference of approximately 18 tons ha^-1 between untreated control trees and the other treatments. The cost to carry out the load adjustment of the most efficient treatment in 'Early Red One' was USD 978.31 ha^-1, and in 'Rosy Glow' it was USD 437.78 ha^-1. In both cultivars, most of these costs were affected by the manual load adjustment (required in any of the evaluated treatments to reach the final number of desired fruit tree^-1/ the desired final number of fruits per tree).

Evaluación de la fitofagia de Tupiocoris cucurbitaceus (Spinola) (Hemiptera: Miridae) en el cultivo de tomate

Lucía Seijas García — 2023-10-25

In Uruguay, tomato (Solanum lycopersicum L.) is one of the main horticultural products in terms of its volume of supply and economic importance. The main pest of protected tomato crops is the greenhouse whitefly (Trialeurodes vaporariorum), which can affect the cosmetic quality of the fruits and cause yield losses. In Uruguay and countries in the region, Tupiocoris cucurbitaceus (Spinola) is commercially available, a native mirid that feeds on whiteflies and other pest arthropods. Several species of mirids have been successfully used for biological pest control in Europe for more than 20 years. Mirids have a zoophytophagous feeding habit; it has been reported that under certain conditions phytophagy can affect tomato crops. The objective of this work was to evaluate the phytophagy of T. cucurbitaceus in tomato crop under controlled conditions. Plant damage was assessed by confining a tomato plant exposed to 20 nymphs or 20 adults of the predator for 72 hours without food supplementation. Control treatments without nymphs and without adults were included. At 0, 3, 6 and 20 days after the predator was removed, the feeding marks on the plant, their location on the different leaves and the height of the plants were recorded. Phytophagy in fruits was evaluated by exposing a tomato fruit for 48 hours to 4 nymphs or 4 adults of the predator and two control treatments without the presence of the predator. Feeding punctures were recorded in the fruits and calyx of tomato at 0, 3, 6 and 20 days after the mirid was eliminated. The results indicated that both nymphs and adults of T. cucurbitaceus caused feeding marks on the tomato plant described as small punctures found mainly in the lower and middle strata of the plant. Tomato plants exposed to adults of the predator were significantly shorter than the control treatment without the presence of adults for all the dates evaluated. While the nymphs caused a reduction in the height of the tomato plants only 6 days after elimination compared to the control without nymphs. Despite finding feeding marks on the calyx and tomato fruits exposed to nymphs and adults of the predator, these did not affect the cosmetic quality of the fruits.

Efecto del uso de aditivos alimentarios sobre parámetros de fermentación ruminal y población de protozoarios en vacas lecheras

Tomás García — 2023-10-11

The need to meet the demands of international markets and to ensure sustainable production practices underscore the challenge of improving rumen fermentation. The use of antibiotics, such as monensin, has achieved this goal, but concerns about the potential development of resistance are prompting research into alternatives such as plant extracts. The aim of this research was to assess the impact of monensin and a blend of plant extracts on ruminal fermentation in dairy cows during the transition and early lactation period within mixed grazing systems. Employing a completely randomized design with repeated measures over time, nine fistulated Holstein cows were allocated to one of three treatments: monensin (MON; 300 mg/animal/day), plant extracts (EXP; 50 g/animal/day) containing trans-cinnamaldehyde, flavonoids, curcuminoids, and piperine, and a control treatment (CON) devoid of additive supplementation. Thirty days prior to the anticipated calving date, the animals entered the prepartum phase, being housed in a compost barn system and consuming a total mixed ration (TMR) that incorporated the additive in the concentrate, as per the respective treatment. Following calving, they were managed within a mixed feeding system, undergoing a grazing session between milkings (05:00 and 16:00 hrs) and confinement post-evening milking. Ruminal fluid samples were collected at -11, +33, and +63 days relative to the average calving date to assess pH, ammonia nitrogen (N-ammoniacal), total volatile fatty acids (AGVt), acetic (C2), propionic (C3), butyric (C4) acids, and protozoa population. Sampling was conducted over two consecutive days at 0, 4, 8, 16, and 24 hrs post-feeding. During the prepartum period, ruminal pH concentration, N-ammoniacal, AGVt, C2, C3, C4, and C2/C3 ratio were unaffected by the treatments; however, the protozoa population was significantly lower in the MON and EXP treatments in comparison to CON (p=0.008). In the postpartum phase, N-ammoniacal and C4 concentrations were significantly lower in the EXP treatment relative to MON and CON groups (p<0.0001 and p=0.0001, respectively), and the protozoa population was lower in the MON and EXP treatments compared to CON (p<0.0001). In conclusion, feed additives constitute a strategy to improve rumen fermentation in dairy cows during transition and early lactation in mixed grazing systems. However, further research into their potential to modulate the rumen microbiota is warranted. A more comprehensive understanding of the use of additives in transitioning dairy cows in mixed systems will prove valuable in increasing the production efficiency of dairy production systems in Uruguay.

La Utilización de raigrás (Lolium multiflorum cv. Bill Max) en la alimentación de terneros

Sofia De Vecchi Thevenet — 2023-10-11

The objective of this work was to evaluate the effect of grazing intensity, which was regulated through the supply of forage (kg dry matter / 100 kg live weight), from a ryegrass pasture (Lolium multiflorum cv. Bill Max) on dry matter intake, forage utilization efficiency, pasture quality and animal behavior and in this way, generate technical coefficients that are useful when planning and making decisions. The experiment was carried out in paddock number six of the Intensive Meat Production Unit of the Experimental Station of the Faculty of Agronomy “Dr. Mario A. Cassinoni” (EEMAC), located in the department of Paysandú, Uruguay. The experimental period was developed during 106 days between May 20 and September 3, 2022. For the experiment, 48 calves of the Hereford breed, born in the spring of 2021, belonging to the EEMAC experimental herd, were used. The animals started the experiment with an average live weight of 121 ± 31 kg, they were sorted into 12 groups (previous stratification by live weight) and these were sorted to the different treatments defined by the forage supply, which were 2,5; 5,0; 7,5; 10,0; kg DM/100 kg of animal LW, respectively. Accordingly, each treatment consisted of 3 repetitions made up of 4 calves grazing an independent plot. Rotational grazing was carried out on the plot for 7 days of occupation, returning to it based on the accumulated biomass. During the experimental period, no significant effect of the treatment (P>0.05) on availability and pre-grazing height was detected. The rejection and the height associated with it showed a quadratic response, where as the forage allocation increased, decreasing increases were recorded, finding the maximum remaining forage and its height, in the 10 % allocation. Utilization presented a negative quadratic response, with the lowest utilization value being observed in the 10% allocation. On the other hand, the consumption of the animals was always higher in the treatment with the highest allocation (10%), in relation to the most restrictive allocation (2.5%). Said consumption presented a quadratic response, so much so that going from an allocation of 2.5% to 5% represented an increase of 51%, while going from the allocation of 7.5% to 10% this increased by only 23 %. Forage allocation did not affect the chemical composition of the offered pasture (P>0.05), but it did improve the crude protein concentration of the selected diet; Based on this, the real consumption of crude protein was higher than that presented by the pasture, evidencing selectivity. No significant differences were found in the grazing activity compared to changes in forage allocation (P>0.05). Regarding rumination and rest, significant differences were detected for the treatment effect (P<0.01). Lastly, there was an effect of the treatment (P<0.05) on the bite rate, which presented a quadratic response that is maximized in FA 7.5%.

Efectos a mediano plazo de la intersiembra de distintas variedades de Lotus y de la fertilización fosfatada en una comunidad de campo natural de basalto

María Jesús García Pintos Berisso — 2023-10-06

This study examined the medium-term effects of overseeding different Lotus species and types, and phosphorus fertilization in a natural grassland community on basalt soil in Uruguay. Total species richness, exotic species richness, annual species richness and coverage of perennial winter grasses and legumes were measured. The results indicate that the overseeding of Lotus corniculatus and Lotus pedunculatus, along with phosphorus fertilization, resulted in changes in the floristic composition, but these changes were reversed in the medium term of five years. After this period, no significant differences were found in total species richness, exotic species richness, and coverage of legumes, annual species, and winter perennial grasses between the treatments and the natural grassland. The overseeding of Lotus corniculatus achieved higher legume coverage in the early years but at the expense of a decrease in species richness. On the other hand, the ones with Lotus pedunculatus resulted in lower coverage but greater species diversity. Exclusive phosphorus fertilization increased the coverage of annual species without reducing species richness. Responses can be attributed to the resilience of the natural campos and the characteristics of the management practices used in the experiment. These findings highlight the importance of further research on the effects of overseeding with legumes and fertilizing with phosphorous and making decisions that allow productivity benefits without compromising the health of the grassland.

Evaluación del efecto de la volatilización de diferentes formulaciones de 2,4-D y Dicamba en el cultivo de soja

Lucía Careac Centanaro — 2023-09-29

The expansión of the area of soybean cultivation and the increased weed of difficult control led to increased use of herbicides, and adaptation of new technologies such as Enlist (whit possibility of application in post emergency of 2,4-D), glyphosate and gluphosinate of ammonium. The coexistence of crops with tolerance and susceptible to herbicide 2,4-D, require a correct use, for safe and efficient use, reducing the risks associated with the application of the herbicide, especially volatilization. Being that it is one of the loss processes that a herbicide can have, and that has a high impact on sensitive crops as well as on the environment and human health. In this context, the aim of this paper was to provide information on same of the main factors that favor the volatilization of herbicides, evaluating the effects of formulations of 2,4-D, and also the herbicide Dicamba, it is relationship to soil moisture, temperature, wind, exposure period and distance from the application area. For this purpose, susceptible soya plants were used as a bioindicator species using a scale of 0 to 10 assess volatilization damage. Three experiments were performed using random complete block design. Two of the experiments were performed under the growth chamber evaluating in the first of them the damage effect of Dicamba and three formulations of 2,4-D, a 15ºC, 25ºC, and 35ºC on wet and dry soil. The second, using the same herbicides as the experiment one, the wet and dry soil with five exposure periods of treatments. And finally, the third experiment went to field, in paddock 6A, of the Mario A. Cassinoni experimental station of the Faculty of Agronomy, where the effects of 2,4-D dimethylamine and 2,4-D choline applied in an area of 30 m² was evaluated from three distances from the application area and 4 exposure times. The highest volatilization damage values were recorded when the temperature was 25ºC. The soil moisture had influence on the experiment 1, being greated damage when it was wet but was not clear effect on the experiment 2. As regards the formulations used, there was a greater effect on volatilization damage with 2,4-D, dimethylamine y Dicamba, with respect to others. The exposure period had a clear effect being the plants exposed inmediatdy after application and those who remained longer, those most affected by volatilized gases. In the field it was found that 2,4-D choline, did not cause volatilization damage beyond 3 m instead of; and that 2,4-D dimethylamine did so up to 20 m from the application area. No clear effects were found regarding wind direction and the layout of the plants are the different directions.

Patrón de pastoreo y movimiento de vacas puras y cruza sobre campo natural bajo distintas ofertas de forraje durante la gestación media y tardía

Joaquín Cabrera Marichal — 2023-09-26

In this work, the effect of forage supply (OF) and cow genetic group (GG) on grazing behavior, rumination behavior, and movement of pregnant multiparous beef cows grazing native pastures was studied. The measurements were made in autumn and winter of 2021, periods corresponding to the stage of middle gestation (114±26 days of gestation) and late gestation (205±26 days of gestation), respectively. This study was carried out in the Experimental Station "Prof. Bernardo Rossengurt" (EEBR - UdelaR), on an area of 49 ha, belonging to a long-term experiment, installed in 2007, where different levels of FA are studied, in breeding cows managed in a continuous grazing system of natural grasslands. The experimental design was an unreplicated factorial arrangement of FA and GG. In autumn, FA levels of 8 and 4 kg DM/kg LW were managed for high FA (HFA) and low OF (LFA), respectively, and in winter the OF in both treatments was 6 kg DM/kg LW. Two GG were evaluated in each OF treatment: Pure cows (PU), from Aberdeen Angus and Hereford breeds, and Cross F1 cows (CR), from reciprocal crosses between Aberdeen Angus and Hereford breeds. Once per season for each plot, the live weight and body condition of the cows were recorded and the forage structure variables were measured. Behavior and movement records were taken for 8 and 10 days, in April and July, respectively. 12 experimental cows were used in each sampling period, which were fitted with a RumiWatch muzzle to record grazing and rumination behavior patterns, and GPS equipment to take location records. In both periods, HFA presented higher forage mass and canopy height (2473 vs 1609 and 1939 vs 1653 kg DM/ha, respectively), while the percentage of area covered by high stratum was twice as high (17 vs 5 and 15 vs 6%, respectively). During mid-gestation, in HFA the grazing time (GT) (P˂0,01) and the bite rate (BR) (P˂0,01) decreased, while the explored area (EA) (P˂0,01) and the percentage of the plot explored (%EA) (P=0,02) increased. CR cows decreased BR (P˂0,01) and increased EA (P=0,02) and %EA (P=0,02), compared to PU. CR cows within AOF decreased GT (P=0,04) and BR (P˂0,01) and increased EA (P˂0,01), compared to LFA. In late gestation, HFA cows decreased BR (P˂0,01) and increased rumination time (RT) (P˂0,01) and EA (P˂0,01). CR cows in HFA decreased BR (P˂0,01). The behavior and exploration at the daily scale and during the grazing session of cows in medium and late gestation suggest that they modified the grazing strategy, associated with the canopy height and the percentage of area occupied by high stratum, which means that the forage is spatially patchy and, in these conditions, the cows decided to modify the harvest costs in terms of time or the rate of intake and rumination, integrating into the decision-making the difference in height between strata, the internal state of the animal and the body condition of the cow, which reflects plasticity in behavior to satisfy intake needs.

Análisis y descripción de la cadena de valor de la colza en Uruguay

Martina Maccio Sorrondegui — 2023-09-26

Because of the important growth of rapeseed in recent years in Uruguay, this paper describes and analyzes the value chain of rapeseed in Uruguay for the 2021/2022 harvest, with the aim of quantifying the Gross Valued Added (GVA) of the chain. Five phases and their respective interaction are defined, in which costs and Gross Valued Production (GVP) are estimate and analyzed. These values are used to create a matrix input-output, resulting in a GVP of $601,576 thousands U$S, costs of $381,162 thousands U$S, and these generate a GVA of $220,414 thousands U$S. From these values, it can be concluded that the agricultural phase is the one that adds the greatest value to the chain (38%), followed by the agricultural services phase, contributing 14%, and the input supply phase, with 10%. In addition, the 77% of the rapeseed production grain it is export destined, where grain transformation processes are minimal, so the collection and export phase only contributes 9% to GVA. The industrial phase represents 8% of the total GVA of the chain because only 23% of rapeseed production is industrialized. Regarding the VAB in relation to the VBP, it can observe that the agricultural phase represents 42% of the VBP, industry 24% and the collection and export phase 11%. Finally, the GVA of the rapeseed value chain in Uruguay for the 2021/2022 harvest is 37%.

Capturas de machos estériles y población silvestre de C. capitata (diptera: tephritidae) en dos disposiciones de trampeo masivo

Agustín Caro Castillo — 2023-09-15

Fruit flies belonging to Tephritidae family are some of the most important pests of fruit growing in the world. Ceratitis capitata and Anastrepha fraterculus are the species that cause economic damage present in Uruguay. As a part of an integrated pest management the alternative to combine mass trapping and the sterile insect technique is proposed. In this trial, the simultaneous use of both techniques was tested, testing two distributions of traps in conjunction with releases of sterile males of C. capitata. The results showed that with the perimeter distribution, a percentage of recapture of released sterile males of 3.3% is obtained, while with the grid format, 14.9% are recaptured. This indicates that the perimeter format would be the best option since a lower percentage of captures of the released sterile males is obtained. Consequently, the combination of both techniques represents a viable option for the control of C. capitata that could improve the traditional tools for the control of this pest.

Efecto del uso de extracto de levaduras o aceites esenciales en sustitución de la monensina en dietas de novillos en engorde sobre la performance a corral y a la faena

Francisco Pelufo de Castro — 2023-09-14

The objective of this study was to evaluate the effect of using yeast or essential oils as substitutes for sodium monensin in finishing diets on the performance, carcass characteristics, and meat quality of feedlot cattle.

Forty-eight Hereford steers, (401 ± 25 kg) were randomly assigned to 12 groups, which were then allocated to one of the three experimental diets. 1) Control (MON): fed completely mixed ration (RTM) ad libitum + 1.5 grams of sodium monensin at 20%; 2) Yeast (LEV): fed with the same RTM ad libitum + 3.0 grams of CELMANAX (company), a commercial product combining yeast culture, yeast extract, and hydrolyzed yeast; 3) Essential Oils (AE): fed with the same RTM ad libitum + 0.3 grams of a source of essential oils, XTRACT Rumiant (company); composed by a mixture of 9.4% eugenol (clove extract), 5.4% cinnamaldehyde (cinnamon extract), and 3.5% capsicum oil (chili extract). Each treatment consisted of 4 repetitions, with each repetition comprising 4 steers fed in the same pen.

The variables studied during the feeding period included dry matter intake (DMI), feed conversion efficiency (FCR), average daily gain (ADG), and behavioral activity. Subsequently, variables on carcass and meat characteristic were studied after slaughter. No statistically significant differences were found among the treatment groups in any of the animal performance variables, such as DMI (MON: 14.09, LEV: 14.43, AE: 14.93, P>0.05), FCR (MON: 6.20, LEV: 6.48, AE: 6.45, P>0.05), or ADG (MON: 2.50, LEV: 2.24, AE: 2.41, P>0.05). Regarding behavioral variables, differences were observed in feeding activity (MON: 0.11, LEV: 0.14, AE: 0.16, P<0.05) and rumination (MON: 0.04, LEV: 0.10, AE: 0.07, P<0.05). Differences were found in backfat thickness (MON: 15.25, LEV: 12.00, AE: 11.25, P<0.05) and muscle color luminosity (MON: 38.88, LEV: 39.03, AE: 41.15, P<0.05). Nonetheless, no differences were detected in marbling (MON: 203.5, LEV: 187.5, AE: 175.0, P>0.05) and pH (MON: 5.51, LEV: 5.48, AE: 5.48, P>0.05). These results suggests that both yeast and essential oils have the potential to replace sodium monensin as a nutritional additive in finishing diets without affecting the productivity, carcass, and meat quality.

Efecto de la aplicación de auxinas de síntesis y el raleo manual de frutos en el tamaño final de mandarina Afourer

Nicolás Vignolo — 2023-09-11

The cultivation of Afourer mandarins, recognized for its organoleptic quality and lack of seeds in the absence of pollination, originates in Morocco and is cultivated in many citrus regions. In the AGRISUR CARL cooperative, in the south of the country, they face the problem of small fruits and low quality in the "El Espinillo" farm. Despite manual thinning attempts, the problem persists. The application of synthetic auxins as chemical thinners has shown improvements in other cases. Therefore, the study seeks to evaluate the effect of these auxins on Afourer mandarin fruits on trees with high flowering and free pollination.

12 treatments with 5 repetitions each one were established. These included auxins applied individually ("ANA1", "TPA1," "ANA2" and "TPA2") and combined on two application dates, as well as combined with hand thinning or hand thinning alone. Two auxin application dates were evaluated and compared with experimental controls and manual thinning. Measured variables included flowering intensity, fruit set, and growth.

The first application of TPA caused extemporaneous flowering, thinning and fruit reduction. The second application combined with the first increased the size and quality of the fruits. Combinations of TPA with manual thinning also showed positive results. ANA apps had minor effects. Manual thinning reduced fruits and yield, but improved fruit size and quality.

In summary, the most effective treatments for Afourer mandarins were the double application of ANA, the combination of ANA with manual thinning and individual manual thinning. These improved the quality of the fruits and reduced the discarded ones. This study highlights the feasibility of using synthetic auxins instead of manual thinning in the production of Afourer mandarins, which could lead to improvements in production quality and efficiency.

Efectos de la densidad de siembra sobre el desarrollo y rendimiento del cultivo de Cannabis para flor medicinal

Antonela Fernández Cirigliano — 2023-08-17

Cannabis cultivation has gained significance in recent years, and Uruguay has not been exempt from this trend. The legalization and regulation of cannabis production and sales for medicinal purposes in the country have opened new opportunities for research and development. In the context of cannabis cultivation, one crucial aspect affecting yield is the planting density. This aspect is currently being discussed in the industry due to its implications on production and costs. Planting density directly influences plant development and modifies the evolution of the crop's leaf area index. This study aims to assess the impact of planting density on the cultivation of medicinal cannabis, specifically focusing on the Monlag variety. Four planting densities were evaluated, with distances of 0.3, 0.7, 1.1, and 1.5 meters between plants within the planting row. The following variables were measured: height, number of nodes per plant, leaf area index, and yield determined by the fresh and dry weight of flowers per plant. The results indicated that planting density had an effect on plant height. Regarding yields per plant, higher yields were observed in taller plants due to their greater development. However, within the range of evaluated densities, yields per hectare did not show significant differences.

Intra-annual characterization of the mean temperature of soil covered at 5 and 10 cm depth based on remote sensing information, for Uruguay.

Martín Francia Camacho — 2023-08-16

Soil temperature (ST) is an important physical property that influences all soil processes; it is a relevant component in the climate system and impacts terrestrial ecological, hydrological, biogeographical, and biogeochemical processes. The measurement of its variability poses difficulties that have limited studies on the spatial-temporal distribution and predictions of ST. This thesis documents the calibration of a model that utilizes remote sensing information (MODIS LST and NDVI) and solar declination for predicting the mean temperature of soil covered at 5 cm depth (TMSc5cm) and 10 cm depth (TMSc10cm), as well as the application of two validated models for the intra-annual characterization of TMSc5cm and TMSc10cm in Uruguay. During the validation stage, TMSc5cm models with R2 of 0.84 and RMSE of 2.3, and TMSc10cm models with R2 ranging from 0.87 to 0.89 and RMSE ranging from 2.1 to 1.8, were selected. When compared to each other, the predictions of TMSc5cm and TMSc10cm maintained a similar relationship to those presented by in-situ observations at the same depth, with slight differences during months of thermal crossovers. It was observed that there is room for improving the quality of in-situ observations and the criteria for selecting satellite information. Preliminary observations highlighted the relevance of studying the effects of forests, soil and subsoil characteristics, and other sources of variability on ST.

Evaluación del efecto de la extracción de madera sobre la compactación de suelo

Valeria Cazzola — 2023-08-15

Forest logging is the stage of the production cycle in the forest system that causes the greatest impact on the soil, being specifically relevant during primary transport or timber extraction. The general objective of this study was to assess the soil compaction generated by the timber extraction. On the other hand, the specific objectives involved the following: (i) to assess the compaction produced by the traffic of three forwarders (FW) with different wood load capacity and pressure on the soil, and (ii) to assess the effect of consecutive passes of the mentioned machines. The experimental site was set up 26 kilometres away from the north of Nuevo Berlín, Río Negro department, Uruguay, in field belonging to UPM, Forestal Oriental company. An 8-years-old Eucalyptus dunnii stand and 0,24 m3/tree were considered, harvested using the Cut To Length system (CTL). Three FW with wood extraction capacities of 18, 20 and 25 tons, respectively, were assessed, thus generating different pressures on the soil.The resistance to penetration (RP) corrected by the gravimetric soil moisture content was evaluated for the three FW loads, for one, two, and three passes of each. Both the control and the passes were subjected to a previous pass of the harvester machine, at the moment of the stand harvesting. The FW traffic was executed on a type of soil vulnerable to compaction, with a low quantity of organic matter as well as low-moisture content, condition caused by a previous forest fire occurred at the stand. The assessment was carried out immediately after the FW passes. The results obtained show the existence of statistically significant differences between the FW and their load capacity, characterized by higher levels of RP when higher pressures are applied on the soil. However, no significant difference was verified between the number of passes, regardless of their magnitude and load.

Efecto de diferente intensidad del uso del suelo sobre propiedades del suelo y la producción de sorgo silero

Manuel Vera — 2023-08-14

In this work, soil and sorghum crop properties were studied in order to understand how various rotations affect in the long term and what effects it has on crop yields, and if possible, eliminate differences through nitrogen fertilizations, regardless of the costs that this requires. The variables studied were on the one hand chemical, with nitrogen and phosphorus at planting, On the other hand, physical properties of the soil such as stability of aggregates and infiltration and finally some components of sorghum such as implantation, number and weight of stems, tillering and finally yield. As for the rotations under study were: two rotations of continuous sorghum, one without and one with coverage, and two rotations of a pasture of fescue, white clover and lotus, with 2 and 4 years of duration. After several years with these rotations the results were clear that the presence of pastures improved almost all the characteristics, and those that did not improve were compensated by the crop itself, it was also observed that extra nitrogen fertilizations did not compensate for the differences between treatments. On the side of the duration of the pastures it was observed that it is favorable mainly when the length allows it to be in good condition, with the soil well covered and with a good specific composition, therefore, as it deteriorates the positive results are declining.

Efectos del fertirriego en el cultivo de maíz

Luis Pedro Gigena Quintela — 2023-08-10

This work seeks to generate information on fertilization strategies with nitrogen (N) in corn under irrigation. The experiment was carried out at the experiment station “Dr. M. A. Cassinoni” in Paysandú, Uruguay during the spring-summer 2020-2021. The experimental design used was completely randomized blocks with 4 repetitions. Said experiment consisted of eleven treatments, of which ten of them took into account different doses and sources of N applied through three different divisions during the crop cycle and a control without fertilization. The doses evaluated were 100 and 200 kg of N ha-1, while the sources evaluated were liquid urea (fertigation) and solid, respectively. Regarding the evaluated fractionations, they consisted of: 1) applications of 100% of the dose to V6, 2) applications of 50% of the dose to V6 and V10 respectively and 3) applications with a weekly fractionation (every 4 days) of the doses between stages V6 and R1, according to physiological scale. When carrying out the statistical analysis, a response to the dose and the source of N used were found. The differences observed in yield in this work showed a positive trend from the increase in the dose and also improvements were observed in the absorption of added N when the application was carried out by fertigation. However, when evaluating the treatment 100 Liq. V6, using half the dose, did not show differences with respect to the superior treatments in relation to the variables analyzed. In this work it was shown that the NG was decisive in performance, since it presented a correlation with superior performance in relation to the PG (R2: 0.87 vs R2: 0.74). In this sense, a positive trend was observed in the NG associated with the increase in the dose and the application in fertigation. While fractional doses of 100 kg of N ha-1 from V6 presented negative effects on the NG. Regarding the PG, a positive trend was observed associated with the increase in the dose and the use of liquid sources. In turn, it is highlighted that applications of 100 % of the dose to V6 have effects on the PG, showing a favorable trend in said component when increasing the dose from 100 to 200 kg of N ha -1.

Estudio de mercado del sector viverista ornamental en el área metropolitana sur del Uruguay

Andrés Mas Espiga — 2023-08-08

Throughout history, ornamental plants have been valued for their ability to beautify and decorate spaces, and have become an important industry worldwide. This study aims to characterize the ornamental nursery sector in the southern metropolitan area of Uruguay, in order to understand the technological tools used in the production and commercialization of ornamental plants, the training of sector workers, the number of family and non-family workers, and the commercial dynamics of ornamental species. To achieve this, a survey was applied to 55 productive units. Although the ornamental nursery sector in Uruguay generates significant employment and commercial flows, its economic importance is often underestimated in the country. The lack of organized and scientific information on this topic underscores the need to generate knowledge that contributes to the formulation of public policies, regulations, and technological, economic, and social improvements in the sector.

Fechas de parto, condiciones meteorológicas y eficiencia reproductiva en vacas de cría

Ignacio Bianchi — 2023-08-07

Livestock breeding in our country is one of the main areas within the agricultural activity, and this activity plays a very important role in the country's economy. This activity is mostly carried out in the open air in natural fields, generally of lower productivity. This is why we must take all the necessary precautions to mitigate the adverse effects of the environment in order to achieve a more efficient and productive livestock farming. Observing the increase of temperatures and solar radiation in certain seasons of the year, we sought to study the effect of the ITH on the reproductive performance of the breeding herd. This work was carried out at the Mario A. Cassinoni Experimental Station in the department of Paysandú, National Route No. 3, Km 363. The trial was conducted with approximately 150 Hereford cows and heifers from the breeding herd of the EEMAC. Taking data on calving date, calf birth weight and gestation diagnosis at the next calving, as well as a series of data on climatic factors such as temperature, relative humidity, wind speed, solar radiation and rainfall provided by the plant production department of the Experimental Station, in order to calculate the ITH and ITHajus. This information was analyzed to calculate if there was a correlation between climatic conditions and birth weight or reproductive efficiency at the next service. Although correlation was found between ITH and calf birth weight, the fit of the curve to the data was low. Taking this into account, measures should be taken to mitigate the effects of heat stress on the animals, without neglecting the rest of the environmental factors, since some of them affect the performance of the herd to a greater extent. It would be of great importance to continue investigating the effects of ITH on the productive and reproductive results of the herd in order to have more information about the moments in which heat stress conditions occur and how this affects the animals.

Desempeño durante la lactancia de corderos Highlander, Milchschaf y sus cruzas con Corriedale

Santiago Rohr Jaume — 2023-08-04

Sheep meat production has gained economic and social importance among small-scale farmers in southern Uruguay. The use of prolific breeds with maternal ability and early growth is presented as a tool to maximize productive results. The aim of this study was to investigate the possibility of improving the productivity of intensive sheep production systems by upgrading a Corriedale (C) flock by Highlander (H) or Milchschaf (M) breeds. Records from lambs born between 2015 and 2021 at Centro Regional Sur, in Progreso (Canelones) were used. The variables analyzed were: birth, lamb marking, and weaning weight; daily and total weight gain during lactation and lamb survival. Genotypes evaluated were purebred Highlander and Milchschaf, and crossbred lambs of these two breeds with Corriedale, generated during the upgrading process. The statistical models fitted included genotype, sex, year of birth, age of dam, type of birth and/or rearing as fixed effects, and marking and weaning ages were fitted as covariables. The results of purebred H and M genotypes were thought to have special significance over the crossbred C genotypes due to the absorptions tendency towards H and M purebreds genotypes. Significant differences were found for birth weight between H and M genotypes, with M showing higher weights. Non-significant differences between H and M genotypes were found in marking or weaning weight. It was concluded that there are no differences in weaning weight between Highlander and Milchschaf, although Highlander could produce heavier lambs at weaning during the upgrading period.

Restauración del bosque nativo luego de la intervención minera

Yanohatt Bálsamo Cardozo — 2023-07-21

In the area of Minas de Corrales, in Rivera, northeastern Uruguay, in 2007 the expansion of a gold deposit called Arenal quarry was decided. This exploitation belonged to the company Orosur Mining and its objective was the extraction of gold. The Arenal quarry was located on the left bank of the Corrales stream, and its expansion involved the construction of a 1.3 km diversion channel on the right bank of the stream through which the intervened stream was channeled. Subsequently, several activities related to environmental restoration were carried out. Civil works began in March 2007 and were completed in June of the same year. The mining intervention project involved the removal of 10.5 ha of forest in the original channel of Arroyo Corrales and the preservation of 13.9 ha of forest patches, the recomposition of the banks of the new channel, soil shaping, revegetation with herbaceous plants and reforestation through the planting of native species extracted from the forest itself. Prior to the removal, all the natural regeneration was identified, marked and planted, 23,000 individuals were transplanted within the remaining forest patches, of which 17,000 were planted in two strata: the low 6.5 ha, adjacent to the watercourse, hygrophilous to mesic and the high: 6.1 ha xerophytic. From 2008 to 2016, permanent monitoring was implemented to characterize the dynamics of the initial restoration phase with planting and irrigation (2008-2009), analyze the growth in collar diameter (DAC, cm) and total height (ht, m), establish the dynamics of mortality and survival, with a quarterly seasonal frequency, in the summer, autumn and spring periods. Eleven species were selected from the most numerous families common to both strata: Phyllanthus sellowianus (Klotzsch) Müll.Arg, Sebastiania brasiliensis Spreng., Sebastiania commersoniana (Baill.) L.B.Sm. & Downs, Blepharocalyx salicifolius (Kunth) O. Berg, Eugenia uniflora O.Berg, Eugenia uruguayensis Cambess., Myrrhinium atropurpureum Schott, var. octandrum, Salix humboldtiana Willd., Scutia buxifolia Reissek, Vachellia caven (Molina) Seigler & Ebinger and Allophylus edulis (A.St.-Hil., A.Juss. & Cambess.) Radlk. We monitored 117 individual trees, 47 trees in the upper stratum and 70 trees in the lower stratum, where the same eleven species were analyzed: S. brasiliensis, S. commersoniana, B. salicifolius, E. uniflora, E. uruguayensis, M. atropurpureum var. octandrum, S. buxifolia, V. caven and A. edulis. Statistical analysis was performed using the GLM model (Generalized Linear Models) to find significant differences between the variables studied and the stratifications performed. Considering a minimum estimated age of 11 years (natural regeneration + afforestation), the following indicators were analyzed: the accumulated increment - IA, the annual periodic increment - IPA and the average annual growth - IMA. The species with the best performance for all variables in the high stratum were V. caven and S. buxifolia, while in the low stratum the two species with the best performance were S. humboldtiana and V. caven. It should be noted that for the survival indicator there were no significant differences between the 11 species and between strata. In the case of Myrtaceae and Euphorbiaceae species, all presented intermediate performance, with E. uruguayensis and S. commersoniana standing out as the best performers in both geomorphological conditions. As for the species A. edulis and B. salicifolius, they could be considered as very slow developing.

El rol extensionista en la transición agroecológica el caso de la ganadería familiar en el norte del Uruguay

Victoria Echenique Melgar — 2023-07-21

In Uruguay, livestock farming occupies most of the country's territory, and family farming plays a central role in the productive cycle. There are numerous family livestock producers, on natural fields, who maintain their way of life and preserve their cultural roots, and may be related to an alternative production model to the productivist one, such as the agroecological model. In addition, since December 2019 the country has a law (Law for the Promotion of Production with Agroecological Bases, creation of the Honorary Commission and the National Agroecology Plan) that proposes family producers as main subjects in the promotion of production agroecology in the country. Within this framework, an investigation was carried out that aims to contribute to knowledge about the role of the extensionist in situations of agroecological transition. As a specific objective, it was proposed to analyze the role of technical assistance and rural extension in the agroecological transition from the point of view of the family producers involved, taking as a reference two technological proposals available to promote agroecological livestock production in the north of the country. in the period 2020-2022. One of them involves the biological control of the tick that arises from the Batoví Organic Institute-Uruguay; the other involves the management of the stocking rate and has been proposed through FPTA 345 "From pasture to Meat" and currently promoted by the Instituto Plan Agropecuario through FPTA 356 "Pasture management". To carry out the research, different qualitative techniques were combined in three stages, some of which were carried out in accordance with the pandemic situation. The field work included the participant observation technique in various activities, twenty semi-structured interviews with family farmers, and two in-depth interviews with leading technicians from the institutions whose technological proposals were considered. The results obtained include aspects related to the expectations and experiences on the technical-producer dialogue of family farmers, and the forms of communication and work methodologies used by extension agents, from which the extensionist role is analyzed and discussed to encourage the agroecological transition in family farming.

Estudio de la calidad de carne de novillos Wagyu puros o cruzas con Angus y Holando

Joaquín Viñoly — 2023-07-12

In this work, the objective was to characterize the variables of the final consumer of animals such as pure Wagyu, crosses with Angus, Hereford and Holando. The study was based on 59 animals that were slaughtered at the Casa Blanca Slaughterhouse (FRICASA) in Paysandú. For the study, a color reading was first made to record organoleptic characteristics, then an analysis of variance was carried out and the data was analyzed using the statistical procedure using the MIXED procedure of the SAS program (V9.4). The results determined that the pure Wagyu animals were the ones that presented the greatest tenderness and acceptability, which allowed us to verify our hypothesis. It was also verified that the effect of the race in the chromatic coordinates was significant with respect to the category for the L* and b* value, but for the a* value, race and category did not show a significant effect.

Efecto de la fecha de siembra y la disponibilidad hídrica sobre el rendimiento de soja

Faustino Rosales Caffera — 2023-06-29

In the 2020-21 agricultural year, a soybean (Glycine max, L.) experiment was carried out at the Faculty of Agronomy. EEMAC ("Dr. Mario A. Cassinoni" Experimental Station), in Paysandú, Uruguay. The objective was to evaluate the effect of the planting date in a high potential short cycle crop under contrasting water conditions. The trial consisted of sowing on three sowing dates (SD) (October 10, November 10 and December 10) each under irrigation and drying conditions. The design used was complete random blocks in divided plots, the largest plot being the three planting dates and the smallest plot being the hydric condition (Irrigation and Rainfed), arranged randomly in the largest plot. Four repetitions were carried out with 6 treatments in each one distributed in 24 Experimental Units (EU). There was no SD interaction with water availability, where the irrigated treatments always yielded more than the dried ones. The SD of October, regardless of the SD, was the one that reached the maximum yields, 3936 kg.ha^-1, on the other hand, observing only the treatments under irrigation, it reached maximum yields of 5180 kg.ha^-1, followed by 3955 kg.ha^-1 and 4030 kg.ha^-1, for the SD of November and December respectively. These results are endorsed by NG. m-2 decreasing from the earliest to the latest SD, these being 3977, 2714 and 2483 for the October, November and December SD respectively. On the other hand, both in terms of NG m-2 and PMG, there was a year effect that there were no differences between November and December. The October SD under irrigation maintained a TCC of 180 kg DM. ha^-1.day^-1 during the reproductive period that accumulates the highest volume of DM at R6, 13831 kg. ha^-1 followed by 11081 and 8696 kg. ha^-1 for the SD of November and December respectively. The SD of November had the lowest CI, 31%, while the SD of October and December did not show differences, being 38% and 40% respectively. The October SD produced a lengthening of the total cycle, the duration of the critical period (PC) increased and its occurrences were brought forward in time. This left larger thermal sums and larger incident cumulative solar radiation (RS).

Heterosis y efectos genéticos en caracteres asociados a la cría en los cruzamientos entre Angus y Hereford

Felipe Scremini — 2023-06-29

The objective of this work was the evaluation of different variables relevant to breeding. In a diallelic experiment between Hereford (H/H) and Aberdeen Angus (A/A) breeds developed between 1994 and 2002 at the Bernardo Rosengurtt Experimental Station of the Faculty of Agronomy-Udelar, Uruguay, differences in direct genetic effects (gIA-gIH) and maternal genetic effects (gmA-gmH) and maternal genetic effects (gmA-gmH) were estimated, differences in direct genetic effects (gIA-gIH) and maternal genetic effects (gmA-gmH), individual (hIAH) and maternal (hmAH) heterosis effects were estimated by means of linear models for body condition at calving (BCC), birth weight (BW), weaning weight (DW) and inter-calving interval (IPP). For birth weight, neither direct nor maternal additive effects were significantly different. On the other hand, for maternal heterosis, significant differences were observed. In the case of individual heterosis there was a tendency (Pr F=0.09) to be 0.049 kg heavier, in the case of maternal heterosis there was an increase of 0.27± 0.11 kg (P<0.05) in birth weight in HA dams, in the case of weaning weight there were no significant differences for direct individual additive effects between both breeds. Maternal additive effects of AA/AA increased by almost 9.95±4.12 kg weaning weight relative to HH/HH (P<0.05), which is consistent with the results of Alenda et al. (1980) who estimated a value of 4.5 kg for this parameter. The individual heterosis estimated for weaning weight was 2.14±1.07 kg, (P<0.05) For body condition, both individual additive effects and individual heterosis, in spite of finding significant differences in favor of these, they do not take relevance since body condition is discriminated with values not less than 0.25 points; in inter-calving intervals no significant differences were seen either, values of individual additive effects and individual heterosis show that there is no relevance in the genotype used for this characteristic.

Susceptibilidad al mildiu de variedades de vid PIWI a campo bajo diferentes manejos fitosanitarios y en laboratorio en condiciones controladas

Dahiana Moreira Marenales — 2023-06-26

Downy mildiu (Plasmopara viticola) is one of the most common fungal diseases that affect vine production, particularly in areas that get precipitation throughout the growing season. The management of this disease requires the use of several chemicals, resulting in higher expenses as well as an adverse environmental impact. Grape varietals known as PIWI have arisen in recent decades that are resistant to fungi-caused illnesses. These stand out due to their high Vitis vinifera genome content, preservation of the bigger resistance genes from American or Asian vines and oenological quality. The aim of this study was to evaluate the sensitivity of 8 PIWI cultivars to the downy mildew under various management and production situations in Uruguay. Five white grape varieties (Fleurtai, Soreli, Sauvignon Kretos, Sauvignon Nepis, and Sauvignon Rytos) and three black grape types (Cabernet Volos, Julius, and UD 72-096) were tested. All of the evaluated grape varieties came from the Vivai Cooperativi Rauscedo, Udine, Italy. Only one of the varieties in this group, which mostly possesses monogenic resistance to P. viticola, carries both resistance loci Rpv 3 and Rpv 12. (Soreli). There were three managements: two under field conditions, the first with integrated management (C4) and the other with reduced use of fungicides to control downy mildew (C3); the third under laboratory conditions on detached leaf. The evaluations were completed during 2021–2022, and the investigations were carried out at the Experimental Station INIA Las Brujas, Canelones, Uruguay. Four totally random blocks (DBCA) with six-story plots served as the experimental unit in the field experiment. The incidence and severity of downy mildiu of a medium vigor shoot were evaluated on four central plants, on the 5, 10, 15, and 20 leaves, counting from the shoot top. For severity, a six-category scale (0 to 5) was employed, with 0 representing no symptoms and 5 representing more than 75% of the leaf with symptoms. The PIWI cultivars Cabernet Volos, Fleurtai, Julius, Sauvignon Kretos, and Soreli all bore the locus Rpv 12 and showed a lesser severity when fungicides were used sparingly to control this disease. In contrast, when the integrates management were applied, severity was kept to a minimum in all the varieties. Under laboratory conditions, the experimental design was a totally randomized design (DCA) using 40 Petri dishes as experimental units, with severity measured as a percentage of infected droplets. The severity in this study never exceeded 50% in any of the varieties, confirming the resistance conferred by the Rpv gene. As part of integrated management, the introduction of resistant PIWI varieties with less usage of phytosanitary treatments brings enhanced environmental sustainability and lower production costs while retaining oenological quality.

Evaluación del efecto de regímenes de poda sobre el crecimiento y calidad de madera en Pinus taeda

Leonardo Gomes Navarro — 2023-06-16

This work was developed in a Pinus taeda´s pruning trial of 19.2 years located near Punta de Cinco Sauces, Department of Tacuarembó, Uruguay. The trial was installed in 2008 on a stand planted in 2003. The experimental design is Complete Random Blocks with three repetitions where five pruning schemes were evaluated. Those schemes comprised different intensity and number of interventions called Light prunning, Medium Light. Medium Severe, Severe, plus a Commercial witness. The objective was to evaluate the effect of different pruning schemes on individual growth, wood quality and compression wood. The variables studied were diameter at breast height, total height, basal area, individual volume, total volume per hectare, volume of the individual pruned cylinder, volume of the pruned cylinder per hectare, maximum diameter of the knotty cylinder, the percentage of wood free of defects and warping (bow, twist and cup). In addition, the impact of compression wood on wood quality and its correlation with deformations was analyzed. The results indicate that pruning intensity and frequency did not have significant effects on individual growth and tree quality for most variables, but did have an impact on individual volume of pruned cylinder and the percentage of wood free of defects. The Light, Medium Severe and Medium Light pruning schemes were the most effective for the production of individual volume of the pruned cylinder up to 9 m height, while the Commercial scheme was the most suitable for the production of wood free of defects considering a basal log of 3 m length. It was concluded that early pruning is important, but it should not exceed 50% of the extraction of the green crown. The study also determined that the presence of compression wood was lower in the Commercial and Medium Light pruning schemes. However, no relationship were found between the presence of compression wood and the deformation variables analyzed. The importance of managing the planted forest from an early age to achieve production objectives is highlighted. This implies to pay timely attention to both density management and pruning to obtain a production that quantitatively and qualitatively optimizes the yield and profitability at harvest.

Keywords: Pinus taeda; pruning severity; growth; crown reduction; clear wood; pruned volume; wood quality, compression wood.

Respuesta a la intensificación productiva del campo natural en el período otoño-invernal

Juan Manuel Mora Gavarone — 2023-06-15

The present study was conducted at the Mario A. Cassinoni Experimental Station of the Faculty of Agronomy of the University of the Republic, located at kilometer 363 of General Artigas Route, in the department of Paysandú, Uruguay, more precisely in an area of 10.3 hectares that are part of paddock number 18 (32° 23' 57" South latitude and 58° 2' 42" West longitude). The evaluation period was between May 9, 2022, and September 30, 2022. This period, which lasts approximately 5 months, is divided into two sub-periods: autumn (May 28, 2022, to August 1, 2022) and winter (August 2, 2022, to September 30, 2022). The objective of the work was to evaluate the autumn-winter productive response of the natural pasture subject to different intensification treatments, managing a target forage offer of approximately 8% LW for both seasons under rotational grazing with 15 days of occupation and 45 days of rest. The experimental design was a randomized complete block (RCBD) with split plots in time, with four replications. The treatments were: a control without intervention (CN); natural pasture improved with legumes, specifically Lotus tenuis cv. Matrero and Trifolium pratense cv. Estanzuela 116 (CNM); and two levels of nitrogen fertilization, 60 kg/ha/year (N 60) and 120 kg/ha/year (N 120) applied in autumn-winter. Additionally, the three intervened treatments are annually fertilized with 40 kg/ha/year of P2O5 in autumn. An analysis of variance between treatments was performed, as well as orthogonal contrasts. The variables analyzed were: present dry matter, available dry matter, remaining dry matter, height of available and remaining forage, daily growth rate, dry matter produced, dry matter disappeared, and utilization percentage. Additionally, a study of botanical composition was carried out with the presence of fifteen botanical groups, percentage of green forage, percentage of bare soil, percentage of soil covered by weeds, total load, average daily gain, meat production per hectare, and forage offer. The study indicates that treatments with added nitrogen fertilizer showed superiority in dry matter production and growth rate, with similar results between the 60 N and 120 N doses. CNM presented intermediate values in these variables. Treatments with added external inputs showed lower contributions from perennial species but no differences in annual species. Biomass production was higher in autumn, but forage quality was better in winter due to a change in botanical composition. Regarding secondary production, it was found that average daily gain did not differ between treatments with added inputs, but it did with the control, and that nitrogen treatments and CNM presented high total meat production, with nitrogen treatments being superior. However, the use of 120 N and 60 N did not differ in productivity, and CNM is an interesting option to increase natural pasture limitations.

Cuantificación de biomasa en pasturas a partir de imágenes tomadas por drones

Jonathan Ribarola — 2023-05-29

In pastoral production systems, to increase the efficiency of both the pasture and the animal, it is necessary to systematically monitor pasture growth and availability. The drone in these systems can speed up and increase the amount of information useful for making decisions. For this reason, the main objective of this work is to evaluate the height measurement and biomass estimation of sown pastures through the analysis of images taken by drones. The evaluations were carried out on a second year fescue pasture located at the Centro Regional Sur (CRS) belonging to the Agronomy Faculty of the Universidad de la República, Uruguay. In the evaluation process, 4 activities were carried out simultaneously: calibration of ruler and RPM for the pasture under study, analysis of images obtained by drones, as well as the creation of a methodology to obtain biomass from images and field data (ruler and/or RPM), and the comparison between measurement methods. The results obtained for the calibration of ruler height and RPM with the available biomass, achieved adjustments with an R² of 0.5241 and 0.5423 respectively.

The DJI Mavic 2 Pro drone was used, which has a UHD camera (ultra HD 5472 x 3648) and flights were made at 60 and 100 meters for the creation of orthomosaics. It was based on taking biomass heights with ruler and RPM in a few georeferenced points in the field and applying a supervised classification (CS) on the generated orthomosaic. Regarding the relationship between the biomass in (kgMS/ha) obtained with the CS using the ruler or RPM and adjusting for the percentage of bare soil (SD), compared to the biomass obtained using 75 measurements of pasture height with ruler or RPM, they achieved adjustments of R²: 0.84 and 0.92 with ruler and of R²: 0.57 and 0.46 with RPM, for flight heights of 60 and 100 m respectively. This work also allowed us to consider a series of advantages and disadvantages that involve the use of drones at present, based on what has been observed in the development of the activity.

Estudio de la selectividad de estratos y comportamiento a nivel de estación de alimentación en vacas pura y cruza a diferentes ofertas de forraje en pastoreo de campo natural

Juan Francisco Goday Aboy — 2023-05-15

During the autumn-winter period of 2021, the ingestive behavior of multiparous gestating beef cows was studied at the level of feeding station, diet selection at bite level and energy intake to determine the effect of forage allowance (FA) and cow genotype (G) on these variables. The experiment was carried out on 49 has of native grassland, that has been maintained at continuous stocking since 2007, belonging to the “Prof. Bernardo Rosengurtt” Experimental Station (EEBR). The experimental design was a non-replicated factorial arrangement of FA and G. The FA was 8 kgDM/kgLW and 4 kgDM/kgLW in autumn for High FA (HFA) and Low FA (LFA) respectively, while in winter it was 6 kgDM/kgLW for both FAs. The Gs were Pure (PU, Hereford and Aberdeen Angus) and cross (CR, F1 reciprocal crosses). The registers of the ingestive behavior were made in April and June, videorecording for 40 minutes in the morning, and same time in the afternoon, for two consecutive days in 3 animals per plot (experimental units). The energy intake was estimated through energy requirements (NRC, 2007), utilizing live weight, evolution of condition score, birth weight and days of gestation as enter variables. Animals responded to the changes in sward structure imposed by the changes in OF, changing their ingestive behavior. Higher FA caused a reduction in the number of feeding stations per minute (FS/min) (6,22 vs 7,66 HFA vs LFA), while the number of steps per FS (S/FS) (1,62 vs 1,49 HFA vs LFA), bites per FS (B/FS) (7,92 vs 7,09 HFA vs LFA) and the percentage of bites made in the upper stratum of the sward (6,98 vs 2,38 HFA vs LFA) were higher in HFA than in LFA. The use of CR animals increased the number of FS/min (7,59 vs 6,29 CR vs PU) and diminished the number of B/FS (6,75 vs 8,27 CR vs PU). Energy intake (12,4 vs 12,1 McalEN/d HFA vs LFA) and condition score (5,2 vs 5,5 HFA vs LFA) were not affected by FA, but energy intake (11,1 vs 13,5 MalEN/d CR vs PU) was affected by G. Energy intake showed a quadratic response to the FS/min number. The information obtained in this work helps us to advance in the knowledge about how changes on the sward structure affect ingestive behavior. Furthermore, we were able to determine that the FS behavior affects energy intake and that this variable is negatively affected by increasing amounts of sward area covered by the high stratum. In addition, it was determined that there are no productive advantages of working with levels of FA similar to those of HFA during mid-late gestation. However, this increase in FA allows a greater forage mass accumulation, which can act as insurance against droughts or other factors that reduce the forage accumulation rate.

Identificación de limitantes y problemas asociados a la adopción de cultivos de servicio en la agricultura

Juan Manuel Sanchis Bisio — 2023-05-08

In recent years, at the national level there has been a change in the agricultural model that has resulted in negative impacts, such as the increase in soil erosion. Based on the national regulations of the Soil Use and Management Plan, efforts have been made to reverse this trend by promoting more sustainable agricultural practices. Among them are service crops, which aim to reduce the amount of time that soil is uncovered. Despite the benefits that technology provides, its use has not been widespread. For this reason, this thesis sought to identify the main limitations that farmers in the country face in adopting service crops. Through three research techniques, a survey (96 respondents), discussion groups (3 groups, 14 participants) and semi-structured interviews (6 interviewees), in which producers and technicians participated, information was collected that allowed characterizing the agricultural systems. of the Central and South Coastal area of the country, identifying internal and external factors that affect the adoption of service crops. In this way, it can be said that currently there is a predominance of agricultural-livestock production systems, in areas that average more than 1000 ha, with a large percentage under lease and with a management approach that prioritizes economic benefit. This last aspect is one of the main limitations for adoption, since it is considered that service cultivation does not provide economic rent and generates expenses. Another challenge for the adoption can be attributed to failures in dissemination, associated with the fact that the final recipients are not representative of national agriculture or that the empirical experience of the producers has not been valued. Therefore, strategies for disseminating service crops as a technology should be rethought.

Efecto de la aplicación de reguladores de crecimiento en el desarrollo radicular de plantines de Eucalyptus smithii

Sofia Bolaño Mendéz — 2023-04-25

Eucalyptus smithii is one of the main species used in the Uruguayan forestry sector; it has arisen as an alternative to the introduction of Teratosphaeria nubilosa which caused several damages to Eucalyptus globulus plantations in 2007. The reason why E. smithii is chosen by forest producers is its wood, pulpable and silvicultural characteristics, as it can be its frost resistance. Nevertheless, plant mortality in early stages of the cycle without a clear diagnosis has been observed in the last few years. The objective of this research was to enhance seedlings quality indicators using growth regulators with effect on root development. The study took place in Saucedo nursery, located in Solis de Mataojo in Lavalleja province in Uruguay. The experiment was conducted in a completely randomized factorial design, with four levels of napthtalene-acetic acid (NAA) and three levels of aminoethoxy-vinil-glycine (AVG), resulting in twelve treatments. The foliar application was made 78 days after sowing. Afterwards, there were three evaluation instances; at 50, 70 and 90 days after the application. Then the morphological parameters were evaluated and the quality of indicators of seedlings estimated. Some treatments had an improvement in quality indicators, as it was the case of intermediate dose ANA 600 / AVG 125 being a possible treatment to be implemented since it obtained the highest DQI value (in the last measurement instance) and achieved seedlings with an improved balance between shoot and root systems without limiting height growth.

Caracterización genética de Bradyrhizobium sp. cepa U531

Mateo Vincent Gerbasi — 2023-04-14

Lotus angustissimus is a legume that is increasingly used in Uruguay as a forage species for the improvement of natural fields. It is currently inoculated with Bradyrhizobium sp. strain U531, the commercial inoculant for Lotus subbiflorus. Under controlled conditions, the symbiotic efficiency of strain U531 in both hosts showed that in L. subbiflorus the biomass yielded 63% compared to the nitrogen control with 10 mM KNO₃, while in L. angustissimus the biomass of the inoculated treatment was 57% higher than the control with N. This suggests that strain U531 has an adequate symbiotic efficiency in L. angustissimus, but also raises questions about why the N control accumulates less biomass than the inoculated treatment. None of the treatments with different concentrations of KNO₃ and sources of N (urea) was able to overcome the production of aerial biomass generated by the nodulated plants. On the other hand, of 5 isolates with different ERIC profiles obtained from L. angustissimus nodules collected in Glencoe, GL2 and GL10 strains induced the same dry biomass as the treatment with the U531 strain, while GL5 strain induced more accumulation of biomass. To estimate the competitiveness of strain U531, the marking with the reporter gene gusA was attempted. The different conjugation times tested did not allow the transposon to be incorporated into the receiver, which indicates incompatibility between the donor and the receiver, so another type of marking should be evaluated, or an evaluation through the identification of ERIC or BOX-PCR profiles. Regarding the effect of the inoculant of L. corniculatus, Mesorhizobium huakuii strain U510 on L. angustissimus, at 21 days in-vitro conditions, efficient nodulation was not induced with this strain.

The genetic characterization of Bradyrhizobium sp. strain U531 included the analysis of the sequence of 16S RNA gene (1,245 nt), the housekeeping genes atpD (330 nt), glnII (525 nt) and recA (368 nt) and the symbiotic genes nodC (203 nt) and nifH (240 nt). The sequence of the 16S RNA gene places this strain within the genus Bradyrhizobium, but the sequence of the concatenated housekeeping genes does not group it with any of the described species, so it is proposed that it is a new species. According to the symbiotic genes, it groups together with a Bradyrhizobium strain isolated from Chamaecytisus proliferus in the Canary Islands and the CNL9 strain, isolated in Uruguay from Lotus uliginosus. Since the ability to denitrify is common among Bradyrhizobium, homologous sequences to the genes involved in denitrification were searched in the genome of strain U531. Through this analysis, sequences with homology to the nir, nor and nos genes, responsible for this pathway, were identified. The phenotypic analysis of the ability to denitrify in an anaerobic medium with NO₃^- does not allow us to ensure that the strain denitrifies.

Ajuste de modelos y estimación de biomasa y carbono para Eucalyptus dunnii en la región sureste del Uruguay

Guillermo Pereyra Zuluaga Facet — 2023-04-10

The aim of this study was to estimate the total aboveground biomass and carbon (C) stock, using a series of relevant dendrometric variables (diameter at base height (DAB), diameter at breast height (DAP), crown diameter (DC), total and commercial height (HT y HC)), for a 10-year-old stand of Eucalyptus dunnii, on the 2.12 CONEAT soils group. The study was conducted in a forest farm named Mi Generala, located in the department of Florida, Uruguay (33° 47´ 52 S, 55º 29’ 00 W), which belongs to Agroempresa Forestal S.A. Ten plots were established that represented 2.57% of the total area of the stand and a traditional forest inventory was carried out considering 332 trees, distributed in five diameter classes. The variables DAB, DAP, DC and H were measured for these trees. Data analysis was performed using the R statistical software, in its Rstudio interface, by fitting generalized linear models. 33 individuals of the population were felled and cubed using the Smalian method and samples of five biomass fractions (leaves, fine branches, thick branches, bark and wood) were obtained for the determination of the moisture content and C in the laboratory. The biomass and C estimates in tons, considering the entire area of the stand (11,67 ha), were 3,518.57 and 1,442.78 Mg, respectively. It was found that the largest amount of biomass and C is present in the stem, followed by thick branches, leaves, and finally thin branches.

La raza Guernsey

Juan Ignacio Porley Casavieja — 2023-03-31

The objective of this work is to generate a general knowledge of the Guernsey breed through results published in different parts of the world where the breed is found. The comparison made with different dairy breeds has the objective of showing the potential of the breed under study in comparison with the others, but especially with the Holstein breed, the main Uruguayan dairy breed.

The milk of this breed is characterized by having high values -in percentage- of fat and protein, and the content of beta casein A2, with proven benefits for human health. On the other hand, other properties characterize it, such as the content of beta carotenes, which generate better aroma and golden color in the milk, being this product called "golden milk".

In terms of published results, under similar production conditions, no significant differences are observed with respect to age at first calving and calving intervals with respect to Holstein. However, a higher efficiency in terms of grain consumption per liter of milk produced is observed in Guernsey compared to Holstein.

Other traits, such as those associated with the adaptability and docility of these animals, make it interesting and with favorable perspectives if it were used in our pastoral dairy production systems.

This work also sought to generate a guide with basic knowledge regarding the importation of ova, semen and embryos for those interested in the inclusion of new genetic resources in our country.

However, it is necessary to take into account that the knowledge of the real productivity of a genetic resource can only be known through studies that include the breed in the country, being this aspect known as genotype x environment interaction.

Given the productive and behavioral characteristics of the Guernsey breed, as well as the quality of the milk produced, it can constitute a very promising alternative in our pastoral dairy production systems.

Distribución temporal de la erosividad de la lluvia en Tacuarembó y Rivera

Juan Manuel Piaggio Plada — 2023-03-29

The Universal Soil Loss Equation (USLE) (Wischmeier & Smith, 1965, 1978) and its revised version RUSLE (Renard et al., 1997) are the models used in the implementation of the current public soil conservation policies in Uruguay. Its rainfall and associated runoff erosivity factor (R) is the average annual value of the EI₃₀ index of all erosive rainfall events that occur in a year for a long series of years. The calculation for a specific location requires pluviographic information of at least 20 years, as updated as possible and with high temporal resolution (<30 minutes) (Panagos et al., 2017). This type of information is usually not available or has limited temporal scope (Klik et al., 2015). To overcome this limitation, 14 years of rainfall records (2000-2014) from a weather station located at "La Corona" Farm, Tacuarembó department were analyzed. Regressions were developed which allowed relating the EI₃₀ index derived in this site with the long-term daily rainfall information (1979-2009) available in the locations of Tacuarembó and Rivera, distant 29 and 80 km from La Corona Farm, respectively. These regressions presented adjusted R² determination coefficients between 0.66 and 0.82. The current recommendations of RUSLE 2 were incorporated into the EI₃₀ index estimates regarding the calculation of the kinetic energy of erosive storms. The estimated R factors for the period 1979-2009 in Tacuarembó and Rivera are 7949 and 8632 MJ mm ha^-1 h^-1 year^-1, respectively. Both values indicate a high erosive potential of the rainfall events. Their return periods are 2.6 and 1.95 years, with probabilities of occurrence of 38.6 and 51.3%, respectively. Summer and autumn concentrate approximately 65% of the average annual erosivity. The estimated R factor values agree with those reported in the bibliography for the area. The methodology used in this work can offer a useful alternative in the estimation of the R factor, as well as its seasonal and monthly distribution, in nearby locations where pluviographic information is not accessible, but long-term rainfall records are available.

Evaluación del comportamiento y calidad poscosecha de cuatro materiales genéticos de guayabo del país (Acca sellowiana (Berg) Burret)

Diego Rodríguez Da Silva — 2023-03-28

The feijoa (Acca sellowiana (Berg) Burret) is a species native to Uruguay, which has aroused interest from producers, researchers, and consumers. In this work, the postharvest behavior of four genetic materials was evaluated by analyzing the physicochemical characteristics of the fruits in refrigerated storage and subsequent shelf life. The guavas were harvested before the moment of "touch picking" in 2021 and stored at a temperature of 5° C and 95% RH. Determinations were made at harvest, 7, 14, and 21 days of conservation, and after 7 days of shelf life (18 °C) after each refrigerated storage period. After harvest, the fruits were characterized by weight and diameter ratio. External and internal color, pulp firmness, weight loss, TSS content, and total polyphenols by the Folin method and antioxidant capacity by the DPPH, FRAP, and ABTS methods, were measured at each evaluation time. The ratio of longitudinal and equatorial diameters marked differences in shape and size, where Artillera and LAF1P3 obtained the highest average fruit weights (82 and 87 g, respectively). Artillera showed the highest firmness at harvest time (28.5 N) and the highest TSS contents together with LAF1P3 (12 and 12.5° Brix, respectively). Regarding the epidermis color, no differences were observed at the time of harvest between materials, but there was an appreciable difference with the course of conservation in Artilera and Cerrillana. Weight loss varied between materials and times, with Artillera having the most significant loss (12%). In all cases, losses were more significant in shelf life, reaching up to 14%. The firmness also decreased with storage and was higher in shelf life. The SST decreased with conservation, being higher in LAF1P3 and Cerrillana. Regarding polyphenols, maintenance of the values was observed. In F1P7, the highest values were obtained on average (120 meq AG/100 g PF). The CAT maintenance of values during the storage period without differences between materials. LAF1P3 and Cerrillana were highlighted by DPPH (1,200 and 1,000 meq Trolox/100 g PF), LMF1P7 and Artillera by FRAP (1,000 and 800 meq Trolox/100 g PF), and LMF1P7 (2,200 meq Trolox/100 g PF) by the method of ABTS. A decrease was observed in the L* parameter except in the LAF1P3 material, while differences were observed throughout the refrigerated storage in the a* and b* parameters. The LAF1P3 and Artillera materials are good alternatives for selling fresh fruit. The LMF1P7 material stood out for its content of polyphenols and CAT, while 154 had a general behavior in conservation, superior to the rest.

Comportamiento agronómico de albariño (Vitis vinífera. l) en diferentes condiciones agroclimáticas

Lucila Bentancor de los Santos — 2023-03-24

The trial was executed in the 2020-2021 season in southeastern Uruguay, in the department of Maldonado, in a commercial vineyard near Pueblo Garzón. The work consisted in evaluating the agronomic performance and enological potential of the white variety, Albariño (Vitis vinifera. L). This document constitutes a background study of this promising variety through the analysis of the varietal response to different geographical conditions of altitude and slope. The hypotheses proposed were: different topographic conditions influence plot temperature (meso-climate); differences in altitude and slope and meso-climate influence the agronomic behavior (phenology, yield) and enological potential (primary and secondary grape composition) of Albariño. The experimental design was a multisite survey where each plot represents a topographic situation taken as a treatment, adding ten treatments in total with two replications per treatment, which had a temperature sensor (TinyTag). The treatments were chosen to represent the distribution of the 4 cardinal points in the vineyard and, based on the characteristics of altitude and slope, each plot was classified into three categories; based on altitude (low category: 72 - 95 masl; medium category: 96 - 117 masl; high category: 118 - 140 masl) and slope (category 1: 0 - 5.8°; category 2: 5.9 - 8.7°; category 3: 8.8 - 11.6°). The analysis of macro-climatic and meso-climatic was made from the calculation of bioclimatic indices. Vegetative growth, phenology, yield components, plant balance and enological potential (primary and secondary grape composition) were also evaluated. The different topographic conditions influenced the temperature of the plots, mainly due to the influence of altitude defined by exposure to the sea. The agronomic and enological potential of Albariño was influenced by the differences in altitude and slope and meso-climate. In plots located in intermediate slope conditions, we observed the achievement of higher yields (14500 kg/ha), lower disease weight and higher sugars (202.5 g/l).

Uso de levaduras o aceites esenciales en sustitución de monensina sódica como aditivo nutricional en dietas concentradas ofrecidas a terneras Hereford alimentadas a corral

Sofia Quintela — 2023-03-17

The aim of this study was to evaluate the potential use of essential oils and yeasts as nutritional additives as a replacement of monensin in calves’ diets under feedlot conditions. It arose in response to the European Union's ban on the use of antibiotics to stimulate animal growth. It was carried out at the “Estación Experimental Mario A. Cassinoni”, Paysandú, Uruguay, precisely in the confinement pens of the “Unidad de Producción Intensiva de Carne”, from August 12 to November 13, 2021.

Thirty Hereford heifers from the EEMAC experimental herd, born in the spring of 2020 and with an average weight of 204 ± 24.3 kg, were used. They were randomly assigned to 3 treatments determined by the additive incorporated to the diet: 1) Control: ad libitum feeding of TMR diet + 0.5 g 20% monensin sodium source; 2) Essential oils: ad libitum feeding of TMR diet + 0.7 g essential oil source; 3) Celmanax: ad libitum feeding of TMR diet + 1 g hydrolysed yeast source. Calves were fed in individual pens, therefore the experimental unit represents each animal and the treatments consisted of 10 individual replicates.

There were no significant differences between the control and alternative treatments for dry matter intake, conversion efficiency and growth, even though a trend was shown towards higher growth by the use of yeast. This suggests that alternative products, such as essential oils or yeast extracts, could be used to replace monensin in the diets of calves as part of a feedlot feeding strategy.

Efecto de tres manejos de la vegetación sobre variables biofísicas en durazneros (Prunus persica (L.) Stokes) 'Dixiland'

Guillermo Long Bertinat — 2023-03-15

The present work was carried out during the 2020-2021 harvest in two orchard in the area of Colonia Valdense, Colonia. The objective was to value the mulch as an alternative tool to the control of spontaneous vegetation in the rows (VEF, by its acronym in Spanish) and its impact on fruit production, plant diversity, physical properties of the soil and the earthworm population. It was decided to carry out descriptive statistics of the management, given the complexity of carrying out an experimental design in the orchard already implanted. Three procedures were observed that have VEF control in common, although they differ in method. Management with mulch (M) consisted of the use of organic mulch (MCV, by its acronym in Spanish), management of mulch+chemical control (M+CQ, by its acronym in Spanish) in the combination of herbicides and MCV, and management with chemical control (CQ, by its acronym in Spanish) was based solely on in the application of herbicides. The M does not differ statistically with the M+CQ in quality and fruit production, and in the physical properties of the soil. It was found that M does not control perennial herbaceous plants, but increases the richness of herbaceous plants in the productive system. The M+CQ is the most efficient management in the control of the VEF. The CQ causes the deterioration of the physical properties of the soil and the loss of biodiversity. The presence of Common Bermudagrass (Cynodon dactylon) was verified only in the handling with herbicides (M+CQ and CQ). The observations of the 2020-2021 harvest for these three VEF managements determine that it is possible to produce peaches in quantity and quality, reducing herbicides in the productive system.

Efecto del uso de aditivos sobre el metabolismo ruminal y la utilización digestiva de alimentos utilizados para producción de leche

Ana Cáceres — 2023-03-09

In milk production systems the use of additives, mainly monensin, is common. Currently, its use is questioned due to the emergence of resistant bacterial strains and the possibility of residues in products for human consumption. Research has been developed in search of alternatives on stabled and in vitro systems, but not in grazing systems as in Uruguay. The objective of this work was to determine the effect of plant-derived bioactive compounds on the rumen utilization of nutrients from different foods (A): pastures and mixed diets, in relation to monensin and a control. Nine Holando-American cows, with 618 ± 13.5 kg of LW, with rumen cannula; were randomly assigned to one of three treatments (T): Control (TC; no additive), Monensin (Tmon; 300 mg/cow/day) and Bioactive extracts derived from plants (TexV; 50 x103 mg/cow/day). In the morning, they grazed alfalfa (AA) with an allocation of 30kg DM/a/d and in the afternoon they received a partial mixed diet (PMD) that contained or did not the additive in the concentrate. Between 50-60 days of lactation, using the in situ technique proposed by Orskov et al. (1980), the degradation kinetics of dry matter (DM), organic matter (OM) and neutral detergent fiber (NDF) of alfalfa hay (HAAE) and the digestibility of HAAE, AA, Chicory (Ach), Fescue (Fest), Oats (AV), Total mixed diet (TMD) were determined, PMD and PMD+AA. For 2 consecutive days, rumen fluid sampling was carried out before access to feeding and at 4, 8, 16, 24 h post-feeding to measure pH, NH₃, VFA and protozoa. Kinetic and digestibility data were analyzed with a randomized design using the MIXED procedure, the model included the T, A effect and their interaction as fixed effects and cow as random effect. For rumen parameters; a repeated measures model including T, h and their interactions as fixed effects and cow as random effect was used. Regarding the degradation kinetics of DM and OM, additives do not affect the degradation rate of alfalfa hay (p>0.05), Tmon has a higher soluble fraction, but a potentially degradable insoluble fraction lower than TexV and TC (p<0.05). The potential degradability of neutral detergent fiber (NDF) is not affected by additives, but reduced the rate of degradation of NDF with respect to TC (p<0.05). The in situ digestibility of food at 48 hours was not affected by the treatments, but treatment x food interaction was detected (p<0.0001), only PMD reduces its digestibility before the use of additives (p>0.05). Tmon and TexV reduce the concentration of NH₃and protozoa (p<0.05). The reduction of protozoa and the decrease in the rate of fiber utilization, caused by additives, could be enhanced in DTMs that use more fibrous foods. Lower ammonium concentration, better acetic:propionic ratio and stability of the rumen environment are encouraging results regarding better efficiency of feed utilization in the rumen.

Fases lunares y su relación con el sexo del ternero en diferentes razas productoras de carne

Iara Soledad Amorín López — 2023-03-09

The objective of this work was to analyze the relationship of the lunar phases in beef cattle calving, as well as the influence of the lunar phase of insemination on the sex of the offspring, during the period 1994-2020. The breeds used were Hereford and Angus, and their respective crosses. The database of the breeding herd of the Bernardo Rosengurtt Experimental Station of the Faculty of Agronomy, located in the department of Cerro Largo, Uruguay, was used. It has a total of 4961 data, registering 3765 births. The lunar phases used were: waxing, waxing fourth, waning, and waning fourth, new and full. It was observed that there is an influence of the insemination moon on the sex of the calves, where it was found that the number of males is greater when the cows are inseminated in the lunar phase of the crescent and new moon. But no influence of the birth moon on sex was found. In relation to births, the highest number occurred in the waxing phase with respect to the waning phase, and within the phases of one day's duration, births were predominant in the new moon, with lower values in the full moon. The distribution of births in the different moons varies with the genotypes of the cows.

Destete precoz a corral

Augusto Baccino Scaglia — 2023-03-07

The present work was carried out between April 20 and August 18, 2021, at the Mario A. Cassinoni Experimental Station (EEMAC), located in the department of Paysandú. The objective was to evaluate in early weaned calves, the effect of the post-weaning feeding system (DPC or DP + grazing supplementation) and the form of concentrate removal (abrupt or gradual) in the DPC at the exit of the pen, on subsequent grazing performance, and its relationship with variables such as apparent digestibility of the pasture and changes in the composition of live weight gain. Fifty-four Hereford calves were used, which had been early weaned at 60 days of age, and managed after weaning in two different feeding systems: pen (early weaning to pen: DPC) and pasture plus supplement (PAS). Of the total number of animals, 18 corresponded to PAS, and grazed a perennial pasture with a forage allowance of 8 kg DM/100 kg live weight, supplemented with an energy-protein ration for early weaning (EM, % CP), offered at a rate of 1% of live weight. The remaining 36 animals were fed four totally mixed rations (RTM; 20% alfalfa hay/ 80% concentrate) that differed in the level of lupine in the concentrate (0, 15, 30 or 45%) with an average concentration of ME and CP of the diets. Animals corresponding to the DPC feeding system were randomly distributed (balanced by diet type) into two groups, and these drawn to one of two forms of transition between diets at the time of leaving the pen and moving to grazing: 1) gradual transition (DPC-G), during the last 5 days prior to exit to pasture (-5 days relative to experimental day 1), concentrate began to be gradually substituted for bulking in the calves' diet until full substitution; and 2) abrupt transition (DPC-A), calves abruptly transitioned (without transition) from pen to pasture on experimental day 1 (4/27/21). The animals in the PAS feeding system were kept supplemented until 4/27/21, and the supplement was abruptly withdrawn. Thus giving rise to 3 treatments. From day 1, all animals, both from the pen and from the pasture, grazed together the same pasture, with a forage DM supply of 5 kg/100 live weight. Animal performance, measured as daily liveweight gain, was not affected by either the feeding system or the post-weaning transition system for the entire experiment, but was affected by the feeding system in the first 0-21 day period, and then by both systems in the 21-65 day and 65-107 day periods. For the animals that were managed in the pen, lower gains were determined during the first 65 days of evaluation, reversing this result from day 65 onwards. Likewise, in the first half of the experimental period, the depressive effect of DPC on GMD could not be attenuated by the gradual removal of the concentrate and its replacement by bulking. As for GMD, it was not affected by either SA or ST. Regarding the composition of the average daily gain, the AOB for the three treatments was not higher at the end than at the beginning; the EGD was increased by the animals that were always grazing, but the opposite happened with the animals coming from the pen that had a reduction.

Fenotipado de la germinación y del peso de semillas de una población de líneas puras recombinantes de Paspalum flavescens y Paspalum plurinerve

Matías Vidal — 2023-03-01

The native field in our region represents the majority of the area in our country. Incorporating warm-season C4 perennial grass into the pastures sowed in our country with winter pastures would add ecological stability to the systems, among other ecosystem services. Paspalum dilatatum is a native species with great forage potential and could cover the forage deficiency from summer to autumn. However, this species shows difficulties for its improvement because of being apomictic. The seeds have dormancy that results in a slow and little synchronized emergence, limiting their productive adoption. Paspalum dilatatum is part of the Dilatata group, an allopolyploid species complex. This complex includes five sexual tetraploids species that do not show breeding limitations, like the apomictic species. These sexual tetraploids present high variability for characteristics with agronomic interest, including seed dormancy. For this task, we harvested seeds from 176 recombinant inbred lines (RIL) obtained from crossing P. flavescens and P. plurinerve. For the RIL population and the parental lines, the weight of 50 seeds and the germination phenotype in two consecutive temperature conditions was measured: First, a more restrictive temperature condition (14 days in alternating 15/25°C, Gp), and later, the optimum temperature condition (7 days in alternating 20/30°C, Gf). A germination index (IGA) was built as an additive product of Gp and Gf. The broad-sense heritability of each variable and the correlations among them were estimated. For all the variables, there were significant differences between the parental lines, which supports previous results that P. plurinerve has lower seed dormancy than P. flavescens. Also, some recombinant inbred lines showed evidence of transgressive segregation. The heritability was high for all variables, among which Gp and IGA showed the higher ones (0.88 and 0.87, respectively), highlighting them as phenotypes with little environmental influence. Significant correlations among all the germination variables were found, but there was no correlation between them and the weight of 50 seeds. The correlation between the variables Gp with Gf was lower than other correlations (r = 0,65), indicating that they may be considered different phenotypes.

Análisis del comportamiento de precios de hortalizas frescas como insumo para la toma de decisiones productivas

Ana Clara Malaquina Scalabrini — 2023-02-28

In Uruguay, the decisions in the productive level are based on the empirical knowledge of the farmers. Having historical database of an extended period of time enable analysis and, according to the results, recommend different strategies.

There are many tools to analyse data, from simple mathematical models that relate two variables to those complex that include many components. The aim of this report is to provide a simple study using basic methodologies that involves time series of monthly prices per kilo of tomato, strawberry and squash, and their correspondent monthly supply. Initially, it is going to be made the conversion from raw to real prices using the Consumer Price Index (CPI). After that there will be detected the outliers that might interfere and make the decomposition of the prices series in the four basic elements: trend, cycle, seasonality and variability. Additionally, there will be included a statistic analysis to study the behaviour of the prices and the supply using the correlation coefficient and the estimation of F and t statistics.

It is highly important to remark that a quantitative analysis is way more valuable if it is complemented with qualitative information. Of those factors that affect the supply and the demand of a good and determine the final price there will be mentioned the most important ones, like the temperature as the main climatic factor and the characterisation and the preferences of the Uruguayan consumer, determinant actor in the chain, who represents the demand.

Efecto de la intensidad de pastoreo sobre la respuesta productiva a la suplementación con grano de lupino en terneros Hereford pastoreando en raigrás Bill Max durante invierno

Wanddy Blanco — 2023-02-27

The experiment was conducted at the Intensive Meat Production Unit (UPIC) of the Dr. Mario A. Cassinoni Experimental Station, Faculty of Agronomy, located at Km 363 of national route No. 3, in the department of Paysandú. The experimental period was from July 7 to September 15, 2020. The objective was to evaluate different types of supplements and their effect on animal performance in calves grazing a ryegrass pasture cv Bill Max. We worked with 48 Hereford calves born in spring 2019 at approximately 8 months of age. At the start of the experiment they had an average weight of 148.3 ± 25.8 kg. The 48 animals were blocked by live weight (3 blocks) and randomly assigned within each block, one of four treatments. Differing in supplementation and forage allocation, each treatment consisted of three replicates of 4 calves each grazing an independent plot. The grazing was carried out in strips with 7 days of permanence, adjusting weekly the PA in each plot according to the availability of dry matter of ryegrass and the weight of the animals. As for the supplementation (offered at 1% of the PV), split lupine grain (Lupinus angustifolius) was used. The treatments grazed with a forage supply of 2.5 kg DM per 100 kg of BW and 5 kg DM per 100 kg of BW. The supplement was fed to the respective treatments in the plots in the morning. The amount on a dry basis was adjusted weekly according to the change in animal weights and DM content of the supplement. Animal performance, measured as average daily weight gain in the supplemented animals was 1.12 kg/day and 0.48 kg/day in the non-supplemented animals, with no significant difference found between the forage allocation variable. The difference in forage availability between treatments and supplement consumption was not significant either. In terms of supplement conversion efficiency, there were no significant differences between treatments. The probability of finding the animals grazing differed in the treatments with supplement, being these the animals that dedicated less time to the activity, while in the resting activity, the supplemented animals had differences with respect to the controls, with more time dedicated to it. The ruminating activity had differences, being the treatments supplemented with lupine the ones that had more time dedicated to this activity. The grazing was carried out in strips with 7 days of permanence, adjusting weekly the PA in each plot according to the availability of dry matter of ryegrass and the weight of the animals. As for the supplementation (offered at 1% of the PV), split lupine grain (Lupinus angustifolius) was used. The treatments grazed with a forage supply of 2.5 kg DM per 100 kg of BW and 5 kg DM per 100 kg of BW. The supplement was fed to the respective treatments in the plots in the morning. The amount on a dry basis was adjusted weekly according to the change in animal weights and DM content of the supplement. Animal performance, measured as average daily weight gain in the supplemented animals was 1.12 kg/day and 0.48 kg/day in the non-supplemented animals, with no significant difference found between the forage allocation variable. The difference in forage availability between treatments and supplement consumption was not significant either. In terms of supplement conversion efficiency, there were no significant differences between treatments. The probability of finding the animals grazing differed in the treatments with supplement, being these the animals that dedicated less time to the activity, while in the resting activity, the supplemented animals had differences with respect to the controls, with more time dedicated to it. The ruminating activity had differences, being the treatments supplemented with lupine the ones that had more time dedicated to this activity.

Efecto del manejo en la productividad estacional y total en avena forrajera

Mauro Long Curbelo — 2023-02-27

The objective of this study was to determine the effect of defoliation management on the seasonal and total productivity of forage oats. The three cultivars of oats used underwent through cuts according to a “3 leaves” defoliation management criterion, which consisted on a defoliation frequency each time that the plot reached 3 totally elongated leaves and leaving 5 cm of sward, and through a “lenient” defoliation management criterion, which consisted on cuttings when the plot reaches 25 cm height and leaving 11 cm sward. The experimental design was a completely randomized blocks with 3 repetitions per treatment: 3 genotypes (La Estanzuela 1095a, INIA Columba y LEAv 1612), 2 defoliation management criteria (3 leaves and lenient) and 2 sowing times (early and late). In each plot the biomass production and nutritional composition was determined, as well as the height and the NDVI value before the defoliation. With an entire plant sample the structure of the plant was also evaluated and during the course of the experiment the number of tillers per square meter was counted. Choosing early sowing dates allows a greater forage production, which differences are spotted mainly in it´s bigger fall production. The 3 leaves defoliation management criterion reaches a greater forage production. Different genotypes have different seasonal and total forage production. E1095a cultivar presents greater biomass and nutrient production during the whole lifecycle, meanwhile INIA Columba achieves high productions in the vegetative phase in detriment of the spring production. LEAv 1612 obtains the lower productions in the vegetative phase but attains greater spring production potential. The settle for the defoliation management criteria to be used takes superior significance in early sowing dates, due to the differentiation between both managements, meanwhile there are no differences between both in the late sowing dates. The present work confirms that there are different responses to the employed defoliation management according to the genotype used, considering that E1095a is apparently insensitive to the management, while INIA Columba and LEAv 1612 have certain grade of response to it, generally in favour of 3 leaves defoliation management. In this work was attested that the quality increasement compensates the lower forage production of the lenient management (except for spring), as there is no difference between the defoliation management criteria in the digestible dry matter (DDM.ha^-1) harvested and even that the lenient management achieves a greater crude protein harvest during the vegetative cycle. Early sowing dates are able to achieve a greater production of nutrients than the late sowing dates. However, only when the forage oats have been sown early, it´s necessary to apply a 3 leaves defoliation management criterion in order to maximize the digestible dry matter production. Late sowing dates allow to apply any of the two defoliation criterions with no difference in nutrient production. A higher tiller population was seen under the lenient defoliation management criterion. The defoliation heights and swards were also seen to have an impact on the plant structure. In this study, the productivity estimation through the NDVI and average plant height on the plot was not sufficiently precise to be able to achieve a good prediction. When comparing the two predictions, using the average plant height seems to be more precise than the NDVI.

Influencia del manejo del suelo en verano sobre la productividad y respuesta al N en el cultivo de trigo

Lucia Marziotte — 2023-02-27

From the year 2000, there has been a change in the national agricultural production, mainly driven by soybean cultivation, which as a result have the decrease of perennial pastures in rotations, also farmers began to implement direct sowing. The increase in the soybean-wheat sequence caused soil losses due to erosion and impoverishment of the level of nutrients in the soil. This added to the increase in wheat yield potential in the last 20 years, caused an increase in the need to add nitrogen via fertilizers. This work aims to evaluate the impact of the soybean crop's presence and level of productivity as a predecessor crop on the following wheat's productivity and nitrogen addition response. The experiment was carried out at the Estacion experimental Mario A. Cassinoni (EEMAC), Facultad de Agronomia, located in Paysandú. The soil is a Typical Eutric Brunosol belonging to the San Manuel unit. Sixteen treatments were carried out in combinations of the soybean predecessor (soybean up to V8, soybean up to R3, soybean at harvest population 50%, and soybean at harvest population 100%) and post-sowing nitrogen management of the wheat crop (RN at sowing, RN sowing - Z22, RN planting - Z30 and not limiting N). The hypotheses proposed were: i) the presence or the level of production of the soybean crop does not impact the productivity of the following crop and does not affect the availability of nitrogen in the soil when planting wheat; ii) nitrogen management cannot reverse the effect caused by the predecessor crop. During the experiment, the temperature and rainfall were similar to and well below the historical average, respectively. The predecessor crop affected the availability of nitrogen during wheat sowing. It also affected the final yield, being soybean up to R3, the one that caused the highest nitrogen in the soil (9,3 ppm), greater water availability at the time of wheat sowing wheat compared to the harvested predecessors (21% increase), and higher yield compared to the harvested predecessors (7434 vs 6175-6283 kg ha^-1). Moreover, nitrogen management influenced the final yield of the wheat crop. The maximum yield was reached when 88 kg de N ha^-1 were applied up to Z 22 (7179 kg ha^-1). On the other hand, the lowest yields were obtained with the RN treatments at sowing and non-limiting N, these being similar, despite having a difference in the added nitrogen of 210 kg N ha^-1. Different responses to the addition of nitrogen were detected depending on the predecessor, being soybean up to V8 the only one that increased yield when 233 kg N ha-1 (non-limiting N) were added, while in the remaining predecessors a yield penalty was observed when nitrogen was applied after Z 22. Moreover, the only nitrogen treatment that did not reach the industry required level of grain protein (11,5 %) was recommended nitrogen at sowing.

Riqueza y abundancia de artrópodos según estructura del tapiz en mejoramientos de campo natural

Kevin Alcántara Perdigón — 2023-02-24

Changes in land use caused by agricultural activities are the main drivers of biodiversity loss in ecosystems. The natural field biome is the most important biome in Uruguay (64.3%), subject to these changes. In the 21st century, the transformations of this biome have accelerated. To evaluate the impact of natural field improvements on biodiversity, the richness of Cicadellidae, Delphacidae and Araneae and the abundance of arthropods were analyzed in the long term (9 years) in plots with: native field, 60 kg N/ha/year, 120 kg N/ha/year and field with Trifolium pratense and Lotus tenuis. The experiment was conducted in paddock number 18, located in EEMAC, Paysandú. In the experiment, 96 samples were taken with entomological nets (12 raids per sampling point) and 96 samples with aspirates, each technique occupied one square meter of surface. The data were analyzed using mixed models and Tukey's test (p-value ˂0.05) to compare the frequency of taxa in each treatment, the variable of analysis was the abundance of the different groups of arthropods, the abundance of Cicadellidae and Delphacidae was analyzed only in collections made with net. Both families were fitted in a simple regression model as a function of the independent variable forage height. Diversity indices: Specific richness, Shannon-Wiener and Simpson were estimated to compare the richness of Morphospecies of Cicadellidae, Delphacidae and Araneae captured with nets in each treatment. In the natural field the average Cicadellidae was significantly higher, while Delphacidae was statistically higher in plots with 60 and 120 kg N/ha. The abundance of spiders did not differ between treatments with netting, but was statistically higher in the 60 kg N/ha treatment than in the legume treatment with the aspiration technique. The average of Hemiptera, Halticus pygmaeus and Nysius simulans was significantly higher in plots planted with legumes with both collection methods. Cicadelids and Delphacidae varied as a function of the interaction between height and days post grazing. Delphacidae adjusted their distribution according to forage height, Cicadelidae showed association only in block 2. Significant regression was found between the predator Nabis capsiformis and the phytophagous Cicadellidae and Morphospecies 1 (Miridae), significant regression was also observed between Araneae and Cicadellidae. The richness of the taxa analyzed did not differ between treatments.

Diversidad de artrópodos y fluctuación poblacional de Trialeurodes vaporariorum en cultivo de tomate bajo invernadero con diferentes sistemas de manejo

Jessica Scanu — 2023-02-24

Tomato (Solanum lycopercisi) is one of the main crops in Uruguay in terms of consumption, and in the south of the country the area of this crop in greenhouses has been increasing in recent years. The greenhouse whitefly, Trialeurodes vaporariorum, is one of the main pests in the greenhouse tomato crops and its control is carried out mainly with the use of insecticides. However, controlling this pest in this way is becoming more and more difficult. Biological control, using entomopathogens and arthropods, is an alternative tool to be included in farm management. The objective of this work was to evaluate and compare the evolution of the whitefly T. vaporariorum population and the diversity of arthropods in greenhouse tomato crops in conventional and organic farms. Sampling was carried out with a frequency of 15 days by visual monitoring of tomato leaves and every 7 days by placing sticky traps. The results obtained were that the whitefly was present in all four farms, but in the conventional farms it was above the intervention threshold, while in the organic farms it remained in low populations throughout the sampling. The diversity of arthropods evaluated through the calculation of Shannon indexes based on species and/or morphospecies was significantly higher in the organic farms.

Respuesta de manzanos 'Rosy Glow' a la poda mecánica en verde

Mauricio Cazzola — 2023-02-13

The apple tree is the main deciduous crop in Uruguay. In recent years the interest of producers to export has increased, however, the high annual climatic variability, together with the shortage of labor have led to adapting new technologies that can lift these restrictions. Thus, mechanical pruning emerges as an option to be evaluated. Therefore, the objective of the thesis is to evaluate the effect of mechanical green pruning on light interception, plant development, production and the quality of the fruit produced in the cultivar 'Rosy Glow'. For this, a commercial establishment was selected in the area of Canelones, Uruguay in the 2019-20 harvest. Crips Pink ‘Rosy Glow’ trees were used on M9, arranged in a randomized complete block design. The evaluated treatments were: Control without pruning (SP), pruning at 12 leaves (P1), pruning at 20 leaves (P2), and pruning at 12 and 20 leaves (P12). Within the experiment, toast length, PAR radiation, yield, overcolor percentage, color analysis, soluble solids, pulp firmness, fruit diameter and weight were evaluated. Among the main results obtained, it stands out that the SP treatment (without pruning) presented the highest interception of light, with a yield of 'Pink Lady' quality fruit (depending on the overcolor) 25% lower than the pruned treatments. Regarding the fruit quality parameters: TSS, pulp firmness and fruit weight did not differ between treatments, on any of the harvest dates. Treatments with mechanical pruning at twelve leaves (treatments P1 and P12) reduced the number of fruits per plant as a consequence of pruning, decreasing the number of manually thinned fruits. The pruning carried out on the second date (20 leaves) did not provoke responses in the growth of toast, nor in the number of fruits. In conclusion, the present work constitutes one of the first evaluations of mechanical pruning in the conditions of southern Uruguay and presents promising results. More years of study and evaluations of the effect on the next productive cycle are necessary to make more conclusive considerations about the use of this technology.

Efecto del material de plantación en la producción de semilla de papa (Solanum Tuberosum)

Bruno Vique Lasserre — 2023-02-09

The traditional seed potato multiplication scheme generates a rapid degeneration of sanitary quality, causing high costs. The objective of this work was to assess the adaptation to our conditions of alternative propagation methods, seeking to reduce volumes and initial costs as a technological alternative for small farmers. The effect of three planting materials was analyzed: seedlings (T1), minitubers less than 3 grams (2.2 in average -T2-), and minitubers over 3 grams up to 6 grams weight (3.4 average -T3-) on the production of basic potato seed (Solanum tuberosum var. Arequita). The final production of basic potato seed was affected by the planting material. The number of tubers was affected, significantly differentiating the treatment with seedlings from the minitubers of 2.2 grams. Regarding the weight obtained, the seedlings showed significant differences in both fresh and dry weight, T1 (443.90 g/m2 PF) doubling T2 (206.17 g/m2 PF) and tripling T3 (151.60 g/m2 PF). In conclusion, the results obtained in relation to the growth of the crop indicate that the use of seedlings in the field is viable, while the use of minitubers requires new trials for their adjustment.

Crecimiento y consumo de nutrientes de lechuga y rúcula en sistema hidropónico NFT

Juan Ignacio Ayres Laporta — 2023-02-08

The hydroponic production system has established itself as a technology of recognized efficiency and widely implemented in developed countries. In South America, the main crop corresponds to lettuce with 49% of the surface of hydroponic crops. In Uruguay, hydroponic production has aroused interest in recent years, with the emergence of various ventures, but there is no systematized information about them. The objective of this thesis was to analyze a commercial NFT hydroponic production system in the south of Uruguay, evaluating two cultivation cycles of Salanova green butter lettuce (Erasmus) and arugula (Astro), emphasizing the evaluation of growth, yield and in the quantification of the consumption of nitrogen, potassium, calcium and sodium of lettuce and arugula, with a cultivation management and particular nutrient solution of a real production situation. The work revealed that the concentrations of nitrate and potassium in the nutrient solution were well below the values sought and recommended by the literature. Regarding sodium, a high concentration was found in the irrigation water, which increased with the daily refills of the nutrient solution made to the system. The average pH was higher than recommended and sought in both cycles and crops. It is confirmed that conductivity is not a monitoring tool for the nutrient solution if it is used as the only parameter. It is recommended to implement a systematic monitoring system of key parameters that allow timely identification of problems and design proposals for improvement in crop management. The application of strategies to improve the characteristics of the water used for the nutritive solution (rainwater, well, filtration) can result in an increase in yields and in prolonging the terms of the renovation of the nutritive solution with savings of water, fertilizers, labor and environmental benefits. This work provides the first national data on production, management and nutrient consumption of hydroponic lettuce and arugula obtained from a real production situation in Uruguay. It also provides a methodology for diagnosing and detecting problems in a hydroponic system, constituting a tool applicable to other soilless cultivation systems.

Curvas de absorción de nitrógeno y potasio en tomate bajo invernaderos con distintos niveles de fertirrigación

Jonathan Lopez Toni — 2023-02-07

Tomato (Lycopersicom esculentum Mill) is the crop that occupies the largest protected area in Uruguay, with 243 ha according to data from the season 2014/2015 (MGAP. DIEA, 2017) and is the second vegetable in terms of entry into the Mercado Modelo. Crop yields have not increased since the 2002-2003 season (MGAP. DIEA, 2017). These yields are lower than those attainable in the region with similar productive resources and good management. The main yield limiting factors identified for season 2014/15/16 were: potassium nutrition in the first place and nitrogen nutrition for spring and summer crops (Berrueta et al., 2019). In order to improve fertigation management at the farm level, the nitrogen and potassium absorption curves (amounts and moments of absorption) for indeterminate tomato grown in spring/summer under greenhouse conditions in Uruguay were determined in this study. Different levels of nitrogen fertilization (deficient, sufficient and excess) were used. The trial was carried out during spring/summer 2019/20 season at the "Wilson Ferreira" experimental station (INIA, Canelones, Uruguay). Tomato cultivar was Lapataia. The trial consisted in three treatments; T1 without additions of nitrogen and potassium, T2 with addition of 100% of the estimated requirements for nitrogen, potassium, phosphorus, calcium, magnesium and micronutrients, and T3 with addition of 150% of the estimated requirements for nitrogen and 100% of the requirements of the rest of the nutrients. It was observed that T3 was the treatment with the highest accumulation of dry matter with 15694 kg ha^-1, followed by T2 and T1 with 15290 kg ha^-1 and T1 13124 kg ha^-1, respectively. Differences in DM production among treatments were observed from 110 DAT onward and were mainly related to DM in leaves. No statistical differences were found in DM accumulated by the fruits nor in yield. T3 showed the highest N uptake (381 kg N ha^-1), followed by T2 (333 kg N ha^-1) and T1 (289 kg N ha^-1), according to the amount of N available for the different treatments. Potassium uptake was higher for T3 (697 kg K ha^-1), without statistical differences with T2 (652 kg K ha^-1). T1 presented the lowest K uptake (515 kg K ha^-1). At the beginning of growing period nutrients uptake were low and the maximum uptake occurred after 90 DAT due to fruit development. 60% of N and 70% of K were allocated to fruits. N uptake was higher at 120-150 DAT, while K uptake was higher at 90-120 DAT. N and K uptake for T1 were high, even without fertilization, demonstrating that soils with similar characteristics are capable of supply nutrients to maintain high growth rates and high yields. The information generated is key to tomato fertilization planning and improving fertigation management, to increase nutrient use efficiency and contribute to more sustainable systems.

Evaluación a turno final del efecto del raleo sobre el crecimiento y propiedades de la madera de Eucalyptus grandis

Karen Yanet Baez Albano — 2023-02-03

In the present work on Eucalyptus grandis is part of a research project of the National Institute of Agricultural Research (INIA). Its main objective was to evaluate the effect of thinning on growth and the properties of Eucalyptus grandis wood. The selected forest is located in the department of Rivera, and the plantation was carried out in the year 2000. The experimental design of the trial was randomized complete blocks, with three repetitions evaluating different intensities of thinning, reaching final remaining densities of 100,150,200,250, 300, 350 and 400 trees per hectare. The thinning schemes were carried out by combining two thinnings which were carried out in 2002 and 2008. The variables analyzed were diameter at breast height, total height, individual volume, volume per hectare, basic apparent density, apparent density wood current, MOE and MOR. From the analysis carried out, it is concluded that thinning significantly influences the growth variables (DAP, Ht, Vi) where with thinning schemes with lower final populations the highest values of these variables are reached, the opposite occurs with Vha where with schemes of thinning with higher final populations, lower values of the variable are obtained. In addition, thinning has a significant influence on the density of the wood and no significant differences were found with the mechanical properties (MOE and MOR) of bending and compression. Therefore, to obtain quality wood that is determined by large diameters, thinning schemes with a lower final density must be reached, which also causes an increase in the density of the wood. In addition, in the present study, correlations were found between density and mechanical properties, so one property can be inferred from the other.

Una evaluación de alternativa de fertilización con fuentes de liberación controlada en el establecimiento de plantaciones comerciales de Eucalyptus grandis

Eduardo Noble Molina — 2023-01-30

The establishment of a commercial plantation of Eucalyptus grandis a year after being planted in a Tacuarembó site with the addition of controlled release fertilizers was evaluated. A total of 12 treatments and a control (unfertilized control) with three replications were applied to the plantation. The treatments are the result of the combination of the factors nutrient release period and applied doses, where for the period of release there are 4 levels: 3 months, 6 months, 9 months and 12 months, and for the doses 3 levels: 6, 12 and 18 grams per plant at the time of planting with Basacote Plus fertilizer (16, 8, 12 + micro). The stand density was 1250 plants per ha.

The survival, growth (divided into its components basal area, height and volume) and nutrient content (N, P, K, Ca, Mg and B) in the leaf were evaluated in this study. In this case, the differences were found mainly in survival where low release periods are related to higher mortality. No significant differences were found in height, volume and foliar nutrient content compared to the control. In the case of the basal area, an effect of the period was found only for the 6-month release period vs. the 12-month release period levels.

From the study, a trend was observed that, as the depth of the soil increased, higher values of the variables basal area, volume, and foliar nutrient content were evidenced.

Caracterización de aislados de Neofusicoccum parvum asociados al cancro de tallos y ramas en Cannabis sativa L. en Uruguay

Elvis Sasia — 2023-01-27

The cultivation of cannabis is relatively new in Uruguay, having a momentum and growth from the year 2013 after the enactment of Law No. 19.172, being the first country in the world to regulate the production of cannabis for recreational, medicinal and industrial use. The crops are distributed throughout the country, having a greater influence in the south and south-east, occupying around 456 hectares in the open air and some 90.000 m² of protected cultivation. The objective of the present work was to characterize isolates of Neofussicocum parvum by means of morphological and pathogenicity methods in Cannabis sativa plants of the variety Fenochis. The isolates were planted in two culture media, PDA and AA with sterile pine needles. In PDA medium, the isolates were incubated at 25 ºC in the dark to characterize the colonies and pigment production at 3, 8 and 16 days of incubation. In AA medium with the addition of sterile pine needles, they were incubated at 25 ºC, with a 12-hour photoperiod of near ultraviolet and fluorescent light for 7 weeks in order to favor the formation of structures and characterize the conidia. Subsequently, the inoculation was carried out in the Phytopathology Laboratory of the Faculty of Agronomy (Montevideo) using three (Cluc F, Migues 1 and Migues 14), inoculating a total of 45 plants distributed in three blocks with five repetitions. The symptoms observed consisted of necrosis at the stem level, with generalized wilting and death of the plant with the advance of the disease, where the production of pycnidia could be observed on the affected tissue. Of the plants with symptoms, isolation was carried out from stem pycnidia, coinciding with N. parvum. This work is the first to test the pathogenicity of N. parvum isolates in C. sativa cultivation, confirming the presence of stem and branch blight in Uruguay.

Caracterización y selección de aislados de Clonostachys spp. para el control biológico del moho gris en tomate

Nicolás Silvera Brunetto — 2023-01-24

Grey mould caused by Botrytis cinerea is one of the most prominent diseases in protected crops, including tomato. This disease can affect any plant organ at any stage of development. Management is mainly based on the use of chemical products; however the selection of resistant strains of the pathogen, the negative effects on the health of workers and consumers, demand the development of control alternatives for crops. In this sense biological control appears as a viable alternative for the protection of horticultural crops. In order to contribute to the development of biocontrol agents for the management of grey mould in tomato, the aim of this work was to characterise six isolates of Clonostachys spp. and evaluate their potential for biological control of grey mould in tomato plants. Based on dual-culture confrontations of six isolates of Clonostachys spp. against the most aggressive strain of B. cinerea. Two isolates, Pay 4 and Pal 14, were selected for evaluation of grey mould control on tomato plants under controlled conditions of humidity and temperature. Of the six isolates, three species were identified: two C. rosea f. rosea, one C. chlorolecua and two C. rhizophaga. Both isolates selected for the plant trial belonged to the species C. rhizophaga and showed potential for biological control of grey mould.

Efecto de la intervención de campo natural con nitrógeno y leguminosas en verano otoño

Diego de Brun Cabrera — 2023-01-17

This research was carried out in the 18^th paddock of the Mario Alcides Cassinoni Experimental Station, of the School of Agronomy, located on the 363^rd km of the National Route No. 3 “General Artigas”, in Paysandú department, Uruguay (32º 20’ 9” South latitude, and 58º West Longitude, 61 ms. N.m). The evaluation period was between October 12th. 2017 and April 18th. 2018, and was divided in 3 sub-periods: spring, summer and autumn. The objective of the experiment was to evaluate the response of the natural field under rotational grazing to the introduction of legumes and fertilization with two doses of nitrogen in forage production, botanical composition, and secondary production.A randomized complete block design was used with 4 repetitions, the treatments being: 1- Natural field without intervention (CN), 2- Natural field improved with Lotus tenuis cv Matrero and Trifolium pratense cv. Estanzuela (CNM), 3- natural field fertilized with 60 kg/ha of N per year (N60), and 4- natural field fertilized with 120 kg/ha of N per year (N120). The three treatments that were intervened were also fertilized with 40 units of P2O5 /ha per year. Fertilization history and nitrogen dose were also evaluated. The variables related to the pasture studied were dry matter produced (MSProd), growth rate (TC), dry matter available (MSD), remaining dry matter (MSR), dry matter disappeared (MSDes), and the variation of the botanical composition. Meanwhile, the evaluations of the animal component were carried out on the variables instantaneous load (CI), average load (CM) and average daily gain (GMD). The results show that nitrogen fertilization increased the MSProd and TC with respect to the CN, a difference that was not observed significant within any of the subperiods but was observed for the entire study period, a behavior that is largely explained by the water restrictions that were presented during the experiment and the high loads supported by nitrogenous treatments, especially during spring and summer. Meanwhile, the CNM presented intermediate values between the control and the treatments fertilized with N, without significantly differentiating from any of them. Within the subperiods, neither did the MSD, MSR or MSDes vary between treatments, although a decrease was observed from each period to the next for the first two variables. Regarding botanical composition, an increase in the participation of winter annual grass species was observed to the detriment of summer perennial grass species in nitrogenous treatments with respect to CN, especially in N120. Meanwhile, legumes did not show a difference in their participation within CNM or any of the treatments without fertilization history, but instead a positive effect of fertilization history was observed on the participation of this family of species in nitrogen treatments, particularly during the summer. Within secondary production, nitrogen treatments supported loads 100% higher than CN and CNM during spring and summer, with N120 showing the poorest animal performance for these subperiods. For the fall, these differences in loads were corrected and said treatment became the one with the best animal performance, keeping the GMD of the other three treatments at values of similar magnitude to each other for the entire period.

Estudio del peso al nacimiento en terneros Wagyu puros y cruzas con Holando y Aberdeen Angus

Sebastián Vera Young — 2022-12-23

The objective of this work was to measure the birth weight of purebred Wagyu calves and crossbred Wagyu calves with Aberdeen Angus and Wagyu with Holland. With this information we were able to establish significant differences between the pure Wagyu calves that weighed 25.93 Kg and the two crosses, the offspring of the Wagyu crosses with Angus weighed 31.91 Kg while that of Wagyu with Holando weighed 29.72 Kg. body condition at calving was a factor that significantly affected the weight of calves at birth, the higher the body condition, the higher the weight at birth. The category of the mother also affected birth weight significantly, the calves born to pure Wagyu heifers weighed 26.35 kg while the calves of pure Wagyu cows weighed 29.44 kg. The incidence of dystocic births was 11%. Regarding the sex of the calves, we found significant differences in birth weight between them, the males weighed 28.75 kg while the females weighed 27.05 kg, which represents 6% more weight in favor of the male. There were no significant differences when comparing the weight at birth of calves born in July, August and September, nor were there significant differences in the NP when comparing the offspring of the different bulls used, there was no paternal effect.

Efecto del riego de verano sobre el crecimiento vegetativo en los cultivares de olivo Arbequina y Frantoio

Guzmán Medina — 2022-12-23

In the last 20 years, olive growing in Uruguay has increased the production area, most of the cases do not have an irrigation system. Currently the main problem in the field is alternative bearing, irrigation being one of the tools to mitigate it. The objective of this work was to evaluate the vegetative growth as a function of the water supply from stone hardening to harvest. Three irrigation treatments (T0: 0% ETc; T50: 50% ETc and T100: 100% ETc) were carried out on 12 Arbequina and 12 Frantoio trees located in INIA LB, Canelones. Eight branches per tree were marked, 4 branches with high flower load and 4 with low flower load. During the growing season, xylem water potential and stomatal conductance were recorded. Every three weeks the number of new nodes generated and the number of fruits per branch were counted. The irrigation treatments were reflected in the evaluated water parameters (water potential and conductance), registering the lowest values for trees under T0 treatment and the highest values for trees under T100. However, the vegetative growth did not show differences from the applied treatments. Between 70 and 75% of the knots generated in the growing season developed prior to the installation of the experiment. The results show a more important effect of fruit load than irrigation treatments, both in Frantoio and Arbequina. The absence of response in our study variables is due to the fact that the range of water potentials in dry land was not within a range that affects the rate of photosynthesis. For future experiments it is recommended, in years of high flowering, to use the flower thinning technique in order to select homogeneous annual shoots.

Efecto de niveles creciente de inclusión de grano de lupino (Lupinus Angustifolius) en dietas de terminación sobre la performance a corral y a la faena de novillos Hereford

Hernan Gonzalez — 2022-12-23

The objective of this work is to evaluate the effect of the substitution level of sorghum grain for lupine grain in the diet on the performance at the corral and at the slaughter of steers in the finishing phase.The lupine inclusion levels evaluated were 0, 15, 30 and 45% of the diet. This work was carried out in the Intensive Meat Production Unit (UPIC) of the Experimental Station “Dr. Mario A. Cassinoni'' (EEMAC), University of Agronomy, located in the department of Paysandú at km 363 of Route 3. It lasted 106 days, beginning the period of confinement of the animals on 8/19/2021, ending on 12/3/2021 with their slaughter. Forty-eight Hereford steers were used, born in the spring of 2019, from the EEMAC experimental herd, which were blocked at the beginning of the experimental phase by live weight in three blocks (light, 361.6 ± 15.6 kg; medium, 392.1 ± 6.9 kg, and heavy, 416.5 ± 6.3). The corral performance variables that were worked on were; weight gain, dry matter intake, conversion efficiency, rump height, ingesting behavior, intake pattern, digestibility and physically effective fiber intake. On the other hand, in the slaughterhouse, variables related to carcass and meat quality were evaluated, such as slaughter weight, hot carcass weight, yield, pH, thickness of subcutaneous fat, muscle color, fat color, marbling and strength of meat. court. The dry matter intake ended linearly (P=0.0082) with the increase of lupine in the diet, there were differences in GMD, this being lower in the treatment with 30% inclusion of lupine. Regarding the conversion efficiency, no observed significant differences were observed at the experimental level (p=0.7911). The DMS and DMO decreased when lupin was included in the diet; these variables were adjusted to a quadratic model (P=0.0095) (P=0.0074), presenting a minimum value when the inclusion of lupin was 31.18% and 30,65% respectively. The ef% NDF was adjusted to a linear model (P<0.0001), increasing its value as the inclusion of lupine in the diet increased. During the behavior, it was observed that the intake activity presented significant differences (p=0.0018) between the control treatment and the treatments with lupine inclusion, presenting a lower intake activity by the animals fed with lupine. This explains why the animals in the 0% treatment are the ones that present less resting activity with respect to the other treatments (p<0.05). Rumination activities and water intake did not present significant differences between treatments (p=0.8077 and p>0.05, respectively). In the characteristics that make carcass quality there were no differences between treatments, in meat quality characteristics, the cutting force was adjusted to a linear model (P=0.0408), the inclusion of lupine favored tenderness. Although the EGS did not present significant differences between treatments, it tended to behave in a positive quadratic way (P=0.0681), with the 30% treatment presenting less dorsal fat thickness. From this experiment, it can be deduced that lupine grain is presented as a great alternative to replace energy sources, in this case sorghum grain, presenting similar productive performance without affecting carcass and meat characteristics.

Efecto de diferentes compensadores de frío aplicados en manzanos en el sur de Uruguay

Sebastián Viazzo Rinaldi — 2022-12-23

One of the factors influencing fruit quality and yields of apple orchards in Uruguay is the insufficient winter cold for the plant to adequately break endodormancy. The objective of this work was to determine the response of apple trees (Malus domestica B.) “Maxi Gala” and “Red Chief” to the application of cold compensating products, to promote the exit of endodormancy state. The treatments consisted in the application of emulsifiable mineral oil (4%), emulsifiable mineral oil (2%) with hydrogenated cyanamide (1%) and calcium polysulfide (6%) at two times. In the “Maxi Gala”, applications were made to 696 and 932 UF for the first and second moment, respectively, and in Red Chief at 757 and 993 UF. The applications dates of the cold compensators were August 6 and 31, with a water consumption of 850 l/ha in Maxi Gala and 1450 l/ha in Red Chief. 50% leaf fall in Maxi Gala was on June 8^th and in Red Chief on May 29^th. Budbreak responses were evaluated from September 22 to October 12. Referring to “Maxi Gala”, there were no significant differences in the time of application of cold compensators. The chilling requirements in this cultivar were already covered at the time of the first application of compensators. However, “Red Chief” did not complete its chilling requirements at the time of the applications and budbreak percentages improved with the application of compensators at the later date. The percentage of buds sprouted in this cultivar increased from 70,38 to 79,74 and from 71,32 to 79,85 in the evaluations of October 6 and 12 respectively. Considering both cultivars, no differences were observed in final budbreak according to the active ingredients used. There were also no differences in the product-timing interaction. In regard to bud break according to their structure, there were significant differences for both varieties studied, with 10% more buds break on one-year shoots than on spur structures.

Efecto de la suplementación con grano de lupino y su procesamiento sobre la performance de novillos Hereford pastoreando sorgo forrajero durante el verano

Pedro Simeone — 2022-12-22

The work presented was carried out in the summer season, between December 30, 2021 and March 7, 2022, at the Mario A. Cassinoni Experimental Station (E.E.M.A.C.) of the Faculty of Agronomy, University of the Republic, located in the department of Paysandú, Uruguay. Fifty-three (53) Hereford steers of 270 kg ± 52 kg LW at a stocking rate of 5.9 UG/ha, randomly distributed and stratified according to their weight, were assigned to three treatments in a randomized block design (DBCA). The witness treatment (T) group that were only in night grazing in weekly strips of forage sorghum BMR assigned to 8% of live weight, being confined with water and shade while the maximum ITH schedule, from 10:00 to 17:00; a second whole lupin treatment (E) where the animals were in the same conditions as the witness with the difference that during the confinement time, they were supplemented at a rate of 1% of the daily LW with whole grain of Lupinus angustifolius; and the third hammermill lupin treatment (Q) in the same way as the previous one with the only difference that the grain was offered hammermill. The effect of supplementation was studied, this being the average daily gain (ADG) of the whole and hammermill treatments, compared to the witness treatment, the result being 0.723 kg/d more for the supplemented animals. The three treatments were found in equal conditions of available forage, height and botanical composition (p-value> 0.05), in turn, no differences were recorded in the remnants between treatments, so the response to supplementation was additional. The ADGs were 0.905a - 0.999a - 0.229b kg/a/d for treatments E, Q and T respectively, resulting in a conversion efficiency (ECS) of 4.4:1. The effect of grain processing did not show impacts on ADG, these being non-significant between E and Q (p-value>0.05) or in ECS 4.6 and 4.1, respectively. By counting and weight of grains/fragments in feces, it was determined for treatment E and Q, 7.8 and 0.14% of grain in feces, these values being significantly different from each other (p-value<0.05), In the case of treatment E, it was found that the weight of the dry grain offered and the weight of the dry grain collected in feces differ statistically, stating a partial digestion of 60%. Finally, the consumption rate of the supplement measured as a % of offered and as kg in the first hour did not differ between the supplemented treatments (p-value>0.05).

Prospección de plagas, hongos y oomicetos asociados a enfermedades en Cannabis sativa L. en el sur de Uruguay

Damián Collazo Uppenkamp — 2022-12-22

Growing cannabis for commercial purposes was recently allowed by law in Uruguay. It is grown for different purposes, including medical, industrial and recreational purposes. There are crops in the 19 Departments of Uruguay and they are mostly concentrated in the southern region. There is little information about the diseases and pests of cannabis plants in Uruguay, their potential damage and management. For this reason, the purpose of this work was to prospect pests and diseases associated with crops in different production types. Farms with field production and with greenhouses were regularly visited, and the laboratory received samples from different production types for different purposes. The sample collection work was carried out in the period from December 2017 to December 2020. The farms were regularly monitored, and visited three or four times, on a case by case basis. Plants with symptoms, signs or damage were observed, and organisms were collected. Disease and pest samples were processed and analyzed in the Phytopathology and Entomology laboratories, respectively, in the School of Agronomy. Microscopic preparations or insect rearing were carried out for pest identification when appropriate. In the case of diseases, samples were analyzed by wet chamber and/or isolation in culture media. Organisms were identified morphologically and in some cases by molecular biology. The organisms identified as potential pests were: Argyrotaenia sphaleropa, Peridroma saucia, Paracles deserticola, Rachiplusia nu, Spodoptera cosmioides, Helicoverpa gelotopoeon, Myzus persicae, Aphis gossypii, Aulacorthum solani, Rhopalosiphum rufiabdominalis, Trialeurodes vaporariorum, Bemisia tabaci, Edessa meditabunda, Nezara viridula, Caliothrips phaseoli, Frankliniella occidentalis, Diabrotica speciosa, Tetranychus urticae y Polyphagotarsonemus latus. Disease-associated species were: Rhizoctonia sp. (root and stem rot) Fusarium sp. (seedling disease, rot of cuttings and seedlings, root rot and in the base of the stem, rot of inflorescences), Fusarium oxysporum f.sp. vasinfectum (rotting of cuttings), Fusarium oxysporum (root and stem rot) Fusarium solani (root and stem rot)Sclerotium rolfsii (withering of plants), Neofusicoccum parvum (canker of stems and branches), Phomopsis sp. (canker of stems and branches), Sclerotinia sclerotiorum (rot stems, rot of branches and inflorescences), Oidium sp. (leaf and inflorescence spot), Alternaria sp. (leaf spot, inflorescence blight), Botrytis cinerea (rotting of cuttings, stems, branches and inflorescences), Fusarium graminearum (inflorescence rot). Cannabis crops in Uruguay are affected by numerous pests and diseases, which are polyphagous or have a wide host range and have mostly been reported as C. sativa pests or pathogens. In this research, no oomycetes associated with C. sativa diseases were isolated.

Validación de un método de adquisición de la condición corporal en vacas de cría

Juan Ignacio Behrens Canavero — 2022-12-22

The main objective of this work was the validation of a method of acquiring body condition in breeding cows. It was based on developing a methodology that would make it possible the determination of the body condition (CC) of AA cows in an objective way, through qualifications of this form images archived by the Cond – Corp device. The operation of the corresponding components was validated, both, the reader, and the device (connected to each other). Through correlation result, it was established that it is possible to determine the level of CC from the observation of images taken by the device. The experiment was carried out in “La Casona”, Casupá, Florida department. The animals used for the experiments were thirty Aberdeen Angus cows, black and red. This work was divided into two stages: the first in the country and the second one, on desk. At the beginning of the practical work, the first cow was used to understand the operation of the components, adjust the height of the placement of the device and, the external memory was extracted, placing it on a computer to corroborate the file. Then, three cows per tube were worked for a better comfort, we proceeded to cap, since, when analyzing the images obtained, due to the movement of the animals, an adequate sharpness was not archived to be able to classify in the next stage of the work. At the end of the tube, a trained observer was placed to rate the body condition of each cow, making it possible to obtain a form with the assessment of each one. The second stage consisted of qualifying the body condition at desk with the images obtained by the Cond- Corp device. To do this, the external memory was extracted, placed on the computer, and the ten photos taken by the device of each cow were downloaded. Once the results were obtained, the correlation of both evaluations collected were calculated, the variation within each cow in the ten photos was analyzed. The correlation coefficient between both methods of estimation was 0,91. Also, the coefficient of determination (r2) was calculated, which was 0,83, while the CC cond-corp model= 0,33 + 0,88 x, indicating that, for each unit of change in the CC of the expert (visual appreciation) CC to desktop changes by 0,88. Finally, the exact coincidences and the differences found of ±0,25 between the ratings of the device and the photos taken by the cellphone were evaluated according to the expert (reference). The results obtained from the device were better, superior exact matches were obtained and, at the same time, the total number of cows that were analyzed none one overstep 0,25, as was the case with the classification from the photos taken by the cell phone.

Efecto de la aplicación de efluentes líquidos de tambo sobre la fertilidad del suelo y la productividad de Festuca arundinaceae

Guillermo Gordillo — 2022-12-22

During the last 30 years, Uruguayan dairy farming sector has experienced a profound transition. The country went from being a net importer of dairy products to export 70% of its production. This transformation was the result of an intensification of the production process, which was not accompanied by planning for the adequate final disposal of the effluents generated. It is known that, if not properly managed, dairy effluents may have negative impacts on the environment, affecting soil, water courses and air quality. On the other hand, there is a global tendency towards dairy effluents valorization. Due to their nutrient loads, and consequently their potential positive effects on soil chemical, physical and biological properties, dairy effluents are beginning to be recognized as resources rather than as waste. Within this context, this thesis proposes to analyze the impact of the application of dairy effluents regarding their effects on soil properties and crop yield. In order to do so, an experiment was developed in Centro Regional Sur of Faculty of Agronomy where dairy effluents (both raw and treated in a lagoon system) were applied to a Festuca arundinaceae pasture. The methodology involved 4 effluent applications according to their N content in order to achieve an annual dose of 200 kg N/ha. The applications were in September 2019, November 2019, May 2020 and August 2020 before which effluents samples were taken to characterize them. Before each application, pasture cuts were made in order to evaluate its yield. The effects on soil properties were studied through samples taken after the last application and pasture cut, 1 year and 6 months after the sowing. Results obtained for the pasture yield and the soil characteristics were compared to those obtained for non-amended control and for urea fertilization. Dairy effluents proved to be highly variable during the course of the experiment, demonstrating the importance of doing chemical analyzes before their application so as to determine the adequate dose to apply depending on the crop requirements. The effluents characteristics also demonstrated the effectiveness of the lagoon system in reducing the effluent’s organic loads. Regarding the soil properties, no negative effects were observed as a result of the effluent application during the course of the experiment. Some positive effects were determined such as the increase in the organic carbon and potassium concentrations. The maximum pasture yield was obtained with the urea application. Still, there was a significant improvement in total pasture yield with the application of effluents in comparison to the control pasture yield. Therefore, dairy effluents may appear as a promising alternative, even though further and longer-term studies should be performed.

Estudios de ecotoxicidad sobre las lombrices Eisenia fetida de los fungicidas utilizados para el manejo de fusariosis del trigo

Mariana Pérez Polanco — 2022-12-21

Commercial fungicides are composed of an active ingredient responsible for the direct and proven action that causes the death of the fungus, and ingredients declared as "inert". The latter, despite their name may have effects on human health, environment and soil biota. However, for the entry of agrochemicals into Uruguay the tests required for fish and bees consider only the toxicity of the active ingredient as a reference. In addition, ecotoxicity tests on worms are not a requirement. Earthworms are a group of soil macrofauna that play a fundamental role in soil structure, chemistry and biology, reducing some fungal diseases, including wheat Fusarium wilt, through the elimination of the initial inoculum. Hence, the need to evaluate which toxic effects commercial formulations have on worms. The objectives of this work were to evaluate the chronic and reproductive effects of two commercial formulations (Prosaro and Swing Plus) on Eisenia fetida and the lethal or acute effects of the commercial fungicide Prosaro on Eisenia fetida. Four ecotoxicological bioassays were performed, two for reproduction and growth (TRC1 and TRC2) and two acute (TA1 and TA2), validated under the corresponding ISO standards and those described by Environment Canada (2007). All were performed in a controlled environment chamber at 20 ± 2°C, with a light/dark cycle of 16:8 h. for 56 days the CRT and 14 days the TA. For the reproduction and growth trials, 5 dilutions were used on a base 10 logarithmic scale, covering from one tenth of the field dose to the x103 field dose. Based on the preliminary results, a narrower range of concentrations of the commercial product used in the acute tests was determined. In the reproduction and growth bioassays, a stimulation in reproduction at low concentrations was seen for both formulations, showing a hormetic effect. No effects were observed on the biomass of the first generation at 56 days of the trial for a concentration equivalent to the field application dose. The lethal concentration values, LC50 (14 days) for Prosaro, obtained in the acute bioassays were (1790.48 mg kg-1 and 1116.67 mg kg-1 in TA1 and TA2 respectively) showed a greater toxicity of the formulation than that registered for the active ingredients in previous acute bioassays. This result contrasts with what was expected, since if we consider a summative effect of the LC50 of the active ingredients, a concentration of 2381 mg kg-1 of the formulation would have been needed to cause the death of 50% of the population. More studies are needed to evaluate the effects of commercial pesticides and their combinations, not only of their active ingredients separately, and also considering longer time scales. These tests allowed us to visualize the significant degree of uncertainty generated by the use of these products, with respect to the earthworm population but also to other soil animals. This effect should be considered in the risk assessment of chemical products, taking into account the direct and indirect contributions that earthworms make to biodiversity in soils, including contributions to human well-being, also called ecosystem services or functions.

Crecimiento de terneros Hereford y Angus pedigrí desde el nacimiento hasta el destete

Martin Castiñeira Rodriguez — 2022-12-21

Goal. Study the growth of calves of the Angus and Hereford races from birth to weaning. Methods. The experiment consisted of the control of the evolution of the living weight of calves of the Cueva del Tigre Cabaña born in the spring of 2020, being 22 Hereford calves and 17 Angus calves. Heavy were performed from birth to weaning monthly from september 2020 to may 2021, at which time the definitive weaning of calves was performed. The heavy one at birth was made with mechanical balance, while for the following heavy a tru test, model s2, digital brand balance was used. Results. It was observed how the EPD is a key tool to be able to select and get a genetic advance towards the goal you want to achieve, without losing the phenotypic point of view trying to achieve a balance between these two aspects, genotype and phenotype. Conclusions. The growth curves for both races from birth to weaning, presented linear adjustments of order 1 without statistically significant differences. The sex of the calf affects both weights at birth and weaning

Lesiones en piel por esquila en ovejas Merino australiano gestantes

Bruno Azpiroz — 2022-12-19

The study was carried out in at a commercial farm located in the department of Salto, 66 km from the city. Pregnant Merino ewes, 2 to 6 years old (4 to 8 teeth) were used, which were shorn by a company accredited by the Uruguayan Wool Secretariat (SUL). The lesions due to shearing were recorded on a total of 498 ewes, with the objective of evaluating the occurrence of lesions in the different areas of the animal’s body according to the comb used and the skill of the shearer. The shearing was carried out in three days, where each day had four sessions lasting two hours each, and five sessions were evaluated in total. The ewes were shorn at random for both the combs and the shearers, recording approximately a total of 100 sheep per shearer, one shearer shearing 98 sheep, and each one shearing 20 sheep with each of the five evaluated combs (Standard, Cover, Beiyuan, R13 modified and R13), which are the most used combs in Uruguay. The shearers were identified with the letter E and a number (E1, E2, E3, E4 and E5) to maintain the anonymity of each one. This information and the tag number, date, breed, property, comb, type of injury (scratch or cut) were recorded on paper. The lesions were classified as R for scratch (superficial, without cutting the dermis) and T for gash (deep, with a cut in the dermis). They were assigned a number according to the length of the cut (1: < 2 cm; 2: from 2 to 5 cm and 3: > 5 cm). Three effects were analyzed (comb, shearer and session) which were considered as fixed effects in the adjusted models. In turn, body condition (CC) was added as a classification covariate in the analysis, where all the sheep whose CC was below 2.75 and all those sheep that were in a CC greater than or equal to it were grouped together. A binomial model was used to determine the probability of occurrence of the lesions (presence/absence) and a negative binomial model to define differences between the means of lesions for each factor. The comb effect (P<0.0001) and the shearer effect (P<0.0001) presented significant differences. Less than 50% of lesions were recorded both at the ventral and dorsal side, where the frequency of occurrence of lesions at the dorsal side was 49.2% and the ventral one was 43.1%. The most affected region was the Croup, where a higher incidence was observed for all the shearers and for the different combs; on the other hand, the least affected region for all the cases of the different shearers and the different combs was the Udder and Vulva region. The combs that registered the least number of lesions were those that left a greater amount of wool (R13 and Beiyuan), while the combs that left a smaller amount of wool caused a greater number of lesions. These combs were Standard and Cover. The differences between the shearers could be due to the experience and ability of each one of them, which makes the performance of the shearer vary.

Efecto del rastrojo y precipitaciones en la efectividad del Sulfentrazone en el control de Amaranthus spp.

Maria Victoria Riccetto Liendo — 2022-12-19

Agricultural production systems in recent times have been intensified by performing double annual cultivation. This means that summer sowings are carried out on stubble from the continuous use of direct sowing, in addition to the fact that there is today a great use of winter covers in order to reduce erosion and achieve greater control of weeds, not only on the basis of to chemicals, but including cultural controls. These cover crops through their stubble can suppress weeds, but may have the disadvantage of interacting with the pre-emergence herbicide, causing a decrease in its effect. On the other hand Amaranathus spp. the greatest control is given by the use of pre-emergence herbicides, one of them being sulfentrazone. The objective of this work was to evaluate the effect of the amount of stubble and the level of rainfall on the effectiveness of the herbicide sulfentrazone in the control of Amaranthus spp. The experiment was installed at the EEMAC under semi-controlled conditions. 100 Amaranthus spp. seeds were sown in pots. in each one. In those treatments that carried oat stubble, the same was placed, simulating the amount of 0, 3000 and 6000 Kg Dm/ha. The herbicide sulfentrazone was applied at different doses, 0, 0.5 L/ha and 1 L/ha (recommended dose). Then the precipitations of 0, 20, 40 and 80 mm were simulated. The evaluations began 5 days after application, counting the cotyledon emergence in each experimental unit. For the first two evaluations, stubble by herbicide and precipitation by herbicide interactions were significant. At 29 and 40 days after application, a triple interaction was verified. In the first evaluations there was a control of Amaranthus spp. by the stubble suppressing emergencies. In the herbicide treatments, the stubble did not generate a decrease in emergencies. Excellent weed control was obtained in all amounts of stubble, and there were also no differences in control between doses of herbicide. As the days passed, the action of the stubble on the herbicide began to be noticed, where the stubble generated a physical barrier retaining the herbicide. The greatest controls of Amaranthus spp. they were given with full-dose sulfentrazone application. Total control was achieved, regardless of the rain generated the day after the application. In the absence of stubble, sulfentrazone control was excellent. The interaction of the stubble with the herbicide varied in time and for the dose used. Without rainfall, and with higher amounts of stubble, 6000 kg/ha, it was essential to apply the recommended dose of the herbicide.

Caracterización de variables a la faena de novillos Wagyu puros o cruza con Angus, Hereford y Holando

Felipe Aramberri Raffo — 2022-12-16

The objective of this work was to characterize the variables at the slaughter of pure Wagyu steers and crosses with Angus, Hereford and Holando. The database of the study consisted of 59 animals that were slaughtered in the Casa Blanca Refrigerator (FRICASA) in Paysandú. For the statistical study, analysis of variance was performed and the data was analyzed using the MIXED procedure of the SAS program. The results determined that the pure Wagyu animals were those that presented higher levels of BMS, and lower levels of EGS, which allowed to verify the hypotheses. In turn, it was verified that the crosses with Angus allow to achieve BMS levels close to those of pure Wagyu, but maintaining levels of intramuscular fat deposition higher than the same.

Impacto de la intensidad de laboreo sobre la producción de biomasa en plantaciones forestales próximas a cosecha

Emiliano Nessi — 2022-12-16

The trials evaluated in this study were located in the province of Rio Negro (Uruguay) at the Santa Elena premises, a estate of the UPM Forestal Oriental company. The main objective of this study is to determine the relationship between tillage intensity and productivity of E. grandis in age close to harvest. In April of 2011, two identical trials in terms of treatment were put in place: one on soil classified as Bromosol (E1) and another trial on a Litosol (E2). The treatments were: cultivation in “compartments” (P), tillage in rows with disc-harrow and ridges (E) and tillage in rows with subsoiler, light disk-harrow and ridges (E + S). The results obtained in E1 suggest that at the age of 8 years and 4 months from the date of cultivation there exists significative differences in growth in favor of the tillage in treatment E when compared to the rest of treatments. Upon treatment E, productivity increased by 40,3% compared to P (measured in m3/ha of wood with bark); and productivity increased by 18,2% comparing treatment E with E+S. In E2, at age 9 years and 3 months post-cultivation, there does not exist differences between treatments based on the analyzed variables.

Crecimiento del ternero con y sin destete temporario

Joaquin Tafernaberry Gonzalez — 2022-12-16

The objective of the work was to study the relationship of temporary weaning on the reproductive performance of cows and the evolution of weight of calves from birth to final weaning in pure Angus animals and animals cross Angus by Hereford. The same was carried out in the Department of Tacuarembó, in the "Belvedere" establishment. The body condition of the cows was studied at three moments: at calving, end of calving, then in the fall a pregnancy diagnosis was made in order to see if the nasal splint applied to the calves affected the reproductive performance of the cow. mother. In the calves, the evolution of live weight was studied from birth to their first year of life, in order to see the effect of the tablet on the weight of the calves.

Evolución de la producción y características de calidad de lana de primer vellón de animales Merino Australiano en un esquema de mejora genética por resistencia a parasitosis gastrointestinales

Juan Gambetta — 2022-12-15

One of the main limitations in the sheep industry in Uruguay are gastrointestinal parasitosis. The two species most involved are Haemonchus contortus and Trichostrongylus colubriformis. However, to alleviate this problem there are various strategies. This work was carried out at the Estación Experimental Facultad de Agronomía Salto (EEFAS), in which a selection program for resistance to gastrointestinal parasitosis is carried out, in which national and foreign genetics are introduced. The objective was to analyze how the selection for the trait of resistance to gastrointestinal parasitosis affects the production of wool in quantity and quality, specifically the father effect on the production of lambs. Data from first shearing of a total of 717 Australian Merino lambs born in EEFAS from 2015 to 2020 were used. Analysis was done on dirty fleece weight (PVS), clean fleece weight (PVL), diameter (DIAM), body weight (PC), staple length (LM) and egg count per gram of feces (HPG). The phenotypic, genetic, and environmental trend for PVS and PVL increased, for DIAM there were no significant variations. The behavior for LM was similar to PC and their trends were upward. For HPG, a slight drop in the phenotypic effect was observed, while it presented a more accentuated negative genetic effect. All the variables increased and decreased in the years of study, mainly due to genetics, since the environment had little influence. By adding genetics directed to a trait (resistance) and selecting animals solely for that trait, the other variables are indirectly modified. The study determined that by adding genetics directed to a trait, it can be improved and then stabilize the other variables through a selection that is not only directed to the trait of interest, but also considers the other traits of productive interest.

Evaluación de la respuesta estral, fertilidad y prolificidad de un protocolo de pre-sincronización de celo con dos dosis de análogo de prostaglandina F2α en diferentes genotipos ovinos

Candelaria Cortizas — 2022-12-13

The aim of this work was to evaluate the reproductive performance of maternal breeds Corriedale (C), Corriedale Pro (CP), Highlander (H) and Merino Dohne (MD), as a response to a protocol of pre-synchronization of estrus with a synthetic analog of prostaglandin (PG). A total of 255 multiparous and nulliparous ewes between 2 and 6 years of age were used. These had an avergae body condition score of 3.6. The experiment was carried out during the reproductive season and ewes were managed on natural and sown pastures throughout the period. The pre-synchronization was carried out using a double PG doses protocol separated by 7 days. Artificial insemination was then performed in visible heat using marker and androgenized wethers. Ewes were inseminated cervically with fresh semen diluted with 1 ml diluent/1 ml semen. The variables analyzed were: estrus dispersion, fertility, prolificacy and fecundity of the total number of synchronized ewes. Oestrus detection to evaluate their dispersion, was carried out 16 days after the second dose of PG and for 7 days. Fertility and prolificacy were measured 85 days after the application of the second dose of PG by transrectal ultrasonography.For the statistical analysis a generalized linear model was fitted useing the SAS OnDemand software. Significant differences were obtained between breeds in terms of oestrus dispersion, and the breeds could be grouped into two groups. Corriedale and Highlander on the one hand, and Merino Dohne and Corriedale PRO on the other, with the latter two showing the lowest dispersion. No significant differences in first mating fertility were observed between MD, H and CP, but there are significant differences between C and CP. Regarding the fertility of the two matings (insemination and rebreeding), the differences between breeds disappear.Significant differences in prolificacy at both first and total mating were observed between H and C, with H having the highest prolificacy and C the lowest. MD and CP did not show significant differences with any of the breeds. Fecundity in CP and H was higher than in C, but without significant differences with MD. We can conclude that pre-synchronization treatment with double dose of PG has different effects on oestrus concentration in the different breeds studied, but in any case the period of oestrus expression is shorter compared to ewes without pre-synchronized.The use of this protocol can be a good alternative to be applied by farmers as it facilitates insemination and flock management, achieving shorter insemination and lambing periods.

Instalación de Paspalum notatum bajo métodos contrastantes de pastoreo ovino en un área de restauración de campo natural

Micaela Garcia — 2022-12-12

The experiment was carried out in the Sheep Unit of the Centro Regional Sur, experimental station of the Faculty of Agronomy, located at km 35 of Camino Folle in Progreso, in the department of Canelones. The paddock N°3 was made in an area of approximately 1 hectare. The evaluation period was from 03/18/2021 to 03/26/2021. The objective of this study was to evaluate how sheep selectivity is affected in a natural range restoration area, under two contrasting grazing methods, rotational and continuous. Specifically, it is proposed to determine the frequency and intensity of defoliation of a native species, Paspalum notatum, which was introduced in the study area from clods from virgin fields. The treatments then were continuous grazing and rotational grazing, in 3 repetitions each. The variables analyzed were number of leaves per tiller, number of tillers per clod, average plot height, average plot dry matter, Paspalum notatum defoliation frequency, Paspalum notatum defoliation intensity, clod and boundary cell defoliation intensity. As results of the experiment, it was obtained that both Paspalum notatum and Cynodon dactylon were more present on the clod and on the border cell, respectively. The type of grazing did not influence the number of leaves per tiller or the number of tillers per clod. It did influence the average heights of the plots, where the initial and final height of the rotary was higher than those of the continuous one. Furthermore, within each grazing method significant differences were found between the initial and final heights. The average DM of the plots did not vary within the treatments for the initial and final measurements. Between the plots of the continuous and rotational treatments, significant differences were found between the availability of DM for the mentioned measurements. The intensity of defoliation of the clods under study was greater than the intensity of defoliation for the border cell, regardless of the type of grazing. When comparing the treatments, the intensity of defoliation of the clods was higher for rotational grazing than in continuous grazing, however, in the neighboring cells there were no significant differences in the intensity of defoliation. The frequency of defoliation of Paspalum notatum tillers was higher in rotational grazing than in continuous grazing, for the three measurement dates. The intensity of defoliation of Paspalum notatum was higher in rotational grazing than in continuous grazing, for the three measurement dates.

Variabilidad a nivel de potrero en producción y calidad del forraje

Federico Geymonat — 2022-12-09

Most dairy farms in Uruguay have forage as the main component of the diet. Achieving high grass consumption is their challenge to achieve sustainable profitability. For this, it is important to consider and quantify the existing spatial variability in production and quality of pastures to manage them efficiently, this being the main objective of this work. The experimental area comprised six paddocks zoned by electrical conductivity, resulting in 12 zones classified as low, medium, and high. All the paddocks presented a mixture of alfalfa and second year dactylis. The C-DAX pasture meter was used to determine the forage biomass in each grazing area during the spring-summer period and, in turn, botanical and chemical composition was determined for each grazing area using the hand-plucking method. Differences were found in the productive and quality variables between the different areas delimited by electrical conductivity. The areas with higher conductivity offered more and higher quality forage, mainly due to a greater presence of alfalfa.

Comportamiento de Eucalyptus grandis frente al ataque de Leptocybe invasa en un ensayo clonal en el departamento de Tacuarembó

Agustin Costa — 2022-12-09

The Uruguayan forestry sector has been characterized by the implementation of large areas with a low genetic diversity, a few numbers of species and from clonal origin. Eucalyptus grandis is currently the most planted species, with more than 250,000 ha of forest plantations older than 3 years. The entry of new pests into the country supposes an eventual health risk that compromises the stability of these monocultures, such as the galling wasp of the eucalyptus Leptocybe invasa (Hymenoptera: Eulophidae). In Uruguay, the presence of this pest insect species was noted for the first time in 2011, becoming a problem for plantations since it was detected. The main damages are associated with the formation of galls on the main veins, leaves petioles, branches and even trunks of young plants, which causes symptoms such as leaves deformation resulting in a reduction of the photosynthetic area and a loss of growth. This generates a state of stress in the plant which predisposes it to the attack of secondary pests or even in severe attacks can cause their death. The objective of this work was to evaluate the susceptibly of different clones of E. grandis to the attack by the galling wasp of the eucalyptus L. invasa, in a clonal trial located in the department of Tacuarembó. A total of 164 clones and 11 commercial controls were evaluated by means of a DBCA consisting of 370 plots distributed in four blocks (stands). The level of damage was measured at the age of 6 months using a visual scale and the model describing its behavior is a Mixed Generalized Linear Model (GLMM), with the Clone variable as a fixed effect and the variables Plot and Block as random effects. No plots were observed without damage, that means, all the clones evaluated showed attack symptoms to a greater or lesser extent. The Deviancy analysis indicates that the Clone variable was significant in the model with a p-value of 7.288e-16, indicating that there is an effect of the genotype on the response to the damage level. However, the post-hoc Tukey Test did not show major differences between the clones evaluated.

Estudio de la vida productiva de vacas de diferentes genotipos en pastoreo en campo natural

Gabriel Mungay Susalla — 2022-12-08

In the present work, associations of the variables are described: number of births throughout the life of each cow and length of productive life. The quantification method that was taken was the number of calvings throughout the productive life of each cow and the number of years of permanence of the breeding cow in the herd, respectively.

The breeds evaluated in the work were: Hereford, Aberdeen Angus, their F1 crosses and their backcrosses. The analysis comprised the records during the period 1994 to 2005.

In this work, the database of the breeding herd of the Bernardo Rosengurtt Experimental Station of the Faculty of Agronomy, located at km 408 of National Route no. 26. They were subjected to similar management, with feeding purely in the natural field. For the analyses, the GLM procedure of the SAS program (V 9.4) was used, the frequencies of cows of each breed with the occurrence of calving only 1 year, 2 years, etc. were estimated. In a similar way, the productive life of different years of duration (1 onwards) was analyzed. The significance of this variable was analyzed using the chi square test (P<0.05).

Significant differences were found for the F1 cross genotypes, while the pure genotypes and the backcrosses did not present differences between them. This is mainly explained by the expression of Heterosis or hybrid vigor that the F1 genotypes have.

Producción estivo - otoñal de un campo natural del noreste sometido a niveles crecientes de sombra

María Florencia García Rodríguez — 2022-12-05

The present work was carried out to evaluate the summer - autumn production of a natural field in the northeast of the country subject to increasing levels of artificial shade. The experiment was carried out in the department of Cerro Largo - Uruguay, on the EEBR site from November 2020 to July 2021. The experimental design proposed was in complete randomly blocks, with 4 repetitions and 5 treatments, which were a natural field control in full sun, 35, 50, 65 and 80% interception of solar radiation by shade mesh. The management carried out consisted of four forage cuts, the first with sheep and the remaining three with a self-propelled mower. It was found that as light availability decreased, the efficiency in the use of radiation of plants increased. Forage growth was evaluated for each period between samplings and the corresponding daily growth rate. In turn, for each cut, height and the available and remaining dry matter, the disappeared dry matter and the percentage of harvest were determined. The ground cover was studied for both the available dry matter and the remaining of each cut. The botanical composition present in the available dry matter from each cur was also evaluated. At all evaluation times, forage production was higher while the radiation interception was higher, in this way the maximum production occurred in the treatment with 80% interception and the minimum in the treatment on natural field with full sun. Regarding the ground cover in the available forage, it was found that the control treatments presented the lowest percentage of green cover and the highest percentage of dry remains, while the treatments with radiation interception obtained a better green/dry ratio in the available forage. The botanical composition also varied according to the interception of the radiation, in shaded treatments a change in the balance between winter/summer grasses was recorded compared to treatments on natural field in full sun. It is concluded that the different levels of solar radiation had effects both on forage production and on soil cover and the botanical composition of a natural field in the northeast of the country.

Preñez a los 18 meses en las razas Angus, Hereford, Braford y Brangus

Juan Diego Otegui — 2022-12-02

The objective of this work was to evaluate the reproductive performance of the Angus, Hereford, Brangus and Braford breeds against an 18 months service under constant conditions in a grazing system. The same was carried out in “La Magdalena” farm, belonging to the firm Los Tordos SA. This property is located 17 km from km. 52 of route 31 in the 12th Police Section of the Department of Salto - Uruguay.

The work was carried out during the year 2022, starting with the practice from March and it should be clarified that all the treatments were under the same conditions.

A sample of 40 heifers of each of the previously mentioned breeds born in the spring of 2020 was used, thus forming a total of 160 animals.

Regarding feeding, the heifers were managed in natural field grazing and 55 days prior to the start of insemination, strategic energy-protein supplementation was implemented to improve body condition and provide microminerals.

With regard to the reproductive issue, two diagnoses of ovarian activity were made and insemination was carried out through a heat synchronization protocol that consists of raising heat for 5 days, synchronizing on day 5 and raising heat for 6 more days in order to cover the entire herd.

The work was carried out during the year 2022, starting with the practice from March and it should be clarified that all the treatments were under the same conditions.

A sample of 40 heifers of each of the previously mentioned breeds born in the spring of 2020 was used, thus forming a total of 160 animals.

Resistencia y resiliencia a la sequía en gramíneas forrajeras perennes c3 y c4

Nicolás Juárez Caraballo — 2022-11-25

Native grasslands are an important source of biodiversity as well as the main forage basis for meat production in Uruguay. Within a context of increasing climatic variability, it is important to promote species capable of adapting to these conditions. An experiment was carried out under controlled conditions in a glass greenhouse, which began on 7^thJanuary 2021 and ended on 1^stMay 2021 at INIA Tacuarembó, Uruguay. The objective was to evaluate the drought resistance and post-drought resilience capacity in both native and exotic species: with C3 (Bromus auleticus, Festuca arundinacea) and C4 metabolisms (Andropogon lateralis, Paspalum dilatatum, Paspalum notatum). A completely randomised design was used with 6 treatment per species, where each of them was associated with a certain soil water availability (5, 10, 30, 50, 75, 90 % of SWA) and 4 replicates per treatment. The experiment was divided into two phases: Phase I of drought resistance, in which plants were exposed to the different SWA levels, and Phase II of drought resilience, in which all treatments were exposed to the same level of SWA (75%). Total biomass, green forage, N and crude protein (CP) contents, water consumption in both phases, daily evapotranspiration (ET) during the drought resistance phase and tillers´ survival at the end of the experiment were quantified. The most drought resistant species were P. dilatatum and P. notatum, followed by B. auleticus, while the least resistant were F. arundinacea and A. lateralis, measured both in biomass production and green forage. Under low SWA, CP content mas greater in all species except for P. notatum, which did not vary with different AD levels. The most drought resilient species was P. notatum. Greatest ET was observed in F. arundinacea, followed by B. auleticus; however, the latter was less efficient in water consumption per forage production unit. C4 species presented the least values for both variables.

Potencial de la hibridación interespecífica para el mejoramiento de Paspalum grupo Dilatata

Lucas Ivan Moura Bentancor — 2022-11-18

Grazing systems in Uruguay do not generally contemplate the inclusion of summer perennial grasses such as those of the Paspalum genus. The incorporation of this functional group of C4 species could contribute to greater biodiversity, as well as to the seasonal stability of production in order to take advantage of the resources available in the summer. Within this genus there are materials that have shown different advantages such as long growing season, tolerance to early frost, and the occupation of niches that could be used by summer weeds of great importance such as Cynodon dactylon. However, they have some disadvantages such as low seed production and susceptibility to Claviceps paspali, which differ depending on the material to which we are referring. Based on the benefits that could mean including these species within the production systems, genetic improvement programs are justified, which have been approached with different strategies. In this matter, the objective of this study was to determine the potential of the interspecific hybridization method between two sexual materials of the Dilatata group, P. flavecesns and P. plurinerve, in order to find alternative ways to the use of apomictic materials, which entail the disadvantages specified above. The same crossing was previously carried out within the Faculty of Agronomy, where transgressive segregation was obtained for other characters of interest in earlier generations. High probabilities of obtaining transgressive segregating lines in more advanced generations were estimated, serving as a starting point for the present work. Biomass cuts were made beginning in the month of May, when all the plants in the population had reached reproductive status, with subsequent drying of the samples, ending with the separation of hardened sheets and sheaths to determine leaf weights and stem respectively. From a single cross, a great variability was obtained, within which the results showed transgressive segregating lines in the F6 generation at the level of the three characteristics studied. These lines may be agronomically evaluated with the aim of obtaining new cultivars in the long term. In addition, a wide range of promising lines was observed that, although they did not exceed the threshold of significance established by the test, could be of interest to take into account in future trials. This cross in particular is a sample of what the interspecific hybridization method is capable of generating, opening the possibility of continuing to study other crosses within the pool of sexual tetraploids that make up the Dilatata group.

Estudio del efecto de dosis y momento de aplicación del regulador de crecimiento (moddus) en producción de semilla de Festuca y Raigras

Juan Ignacio Aramendia Gambetta — 2022-11-17

Fescue (Festuca arundinaceae) and annual Ryegrass (Lolium multiflorum) are forage crops with very good productivity, used in Uruguay mainly under grazing for livestock: meat, milk and wool. The seed production of these species is relevant in the development of the main agricultural activity in the country. Therefore, the demand for forage seed in Uruguay will depend mainly on the demand for forage by the most intensive livestock systems, with fescue and ryegrass being the most widely used species.

It is considerate that the seed production historically average yields obtained are low in relation to the potential of these species. This could be attributed, among other factors, to the fact that under certain growth conditions the plant lodge under its own weight. There are changes in crop management that include strategies to improve production efficiency and reduce the gap between potential yield and yield obtained in the field. Within these changes in management is the use of new technologies such as growth regulators.

The work was carried out in the field in different commercial crops of producers and the samples were analyzed in the Seed Analysis Laboratory of INIA (Instituto Nacional de Investigación Agropecuaria) belonging to the experimental station La Estanzuela located in the department of Colonia, Uruguay. Three trials were carried out, two on Festuca Arundinacea cv. Rizar, one with irrigation and one without irrigation, and one on Lolium Multiflorum cv. INIA Escorpio with irrigation. In all cases, four treatments were carried out based on the Moddus growth regulator: control (without application), 400cc, 400cc + 400cc and 800cc. Three repetitions were made for the case of Festuca Arundinacea and two for Lolium Multiflorum (pivot operation).

The objective was to evaluate the effect of the use of Moddus in fescue and annual ryegrass seed fields, dose and time, on seed yield, yield components, seed quality and seed losses in the harvest process.

The results obtained indicate an excellent yield potential of the crops studied, in comparison with previous studies in Uruguay and in some cases, in comparison with regions with better environmental conditions for the production of seeds of these species. An effect of the use of the growth regulator on the reduction of the height plants was obtained for two of the three trials evaluated.

Despite this, the tests carried out did not allow the detection of effects of the applied treatments of the TE growth regulator on seed production in the Rizar fescue and the INIA Escorpio ryegrass.

Efecto de diferentes estrategias de manejo durante el período destete – encarnerada en ovejas sobre las variables productivas, sanitarias y reproductivas

Martina Verdaguer — 2022-11-17

The aim of this study was to evaluate the effect on sanitary, productive and reproductive aspects in different strategies in the sheep 's management during the dry period. It was held from the 14th of January 2021 to the 19th of May at the Centro de Investigación y Experimentación Dr Alejandro Gallinal (CIEDAG) of Secretariado Uruguayo de la Lana, in Cerro Colorado, Florida, Uruguay. Nevertheless, the experiment will be continually held for the next two years.

There were 210 Corriedale ewes that were classified at weaning according to its liveweight (PV), condition scoring (CC), dentition and reproductive antecedents. All animals considered were homogeneously allocated in three randomly selected treatments with two repetitions each one. The treatments were: control treatment, grazing nature pastures in a continue stocking rate (4 animals/ha); confinement in an area of 11,1m²/animal with water and shade administration and a diet of pasture hay; confinement in a diet base on 200 grames/animal/day of corn and hay.

Before establishing the confinement, the animals were dosed with an anthelmintic of known efficiency and submitted to a General Objective Exam (GOE) to ensure sanitary status. The treatments started at the weaning and lasted 39 days, at its end a flushing started for 30 days with a diet based on Festuca arundinacea and Lotus corniculatus pasture. On the 15th day of the flushing the mating started for 41 days with 3 rams per 100 ewes.

The aspects evaluated were: parasite status with HPG, liveweight, condition scoring, blood metabolites, pregnancy, prolificacy and twin rates. The hypothesis is that the different strategies resulted in different condition scoring and liveweight evolution, that could be verified in different blood metabolites evolution. However, the different treatments involve could not result in different reproductive rates as long as the animals could recover live weigh and condition scoring during the mating. In sanitary terms, if the environmental conditions are the required the animals confined could present lower HPG results than the one grazing.

Efecto de los cultivos cobertura sobre la recarga de agua, nitrógeno en el suelo y la productividad del maíz

Pablo Leiva — 2022-11-09

In Uruguay agriculture been increasingly important in many ways in many cases generating increasing continuous cropping rotations and handling based on obtaining one crop per year. In these situations leaves a long fallow period in the winter, when the ground is bare. To achieve sustainability of the production system based on grains, should improve the carbon balance through an increased supply of plant biomass. In this sense, hedge crops are agronomic tool ideal because they play the role of providing carbon, maintain the soil covered, recycle nutrients and produce a new entry to the system stubble (Siri\ and Ernst, 2011). This paper seeks to test the effect that different cultures have winter covers the evolution of moisture and nitrate in soil and its impact on the cultivation of maize. For this experiment was conducted in the department on a floor Paysandú Eutrico Brunosol Tipico. The design was a randomized complete factorial with three replications hedges being the main plot and nitrogen doses lower plot. The cover types were used, four grasses (Avena Byzantine strigosa Avena, Lolium multiflorum and Triticale), three legumes (Trifolium alexandrinum, Vicia sativa, Pisum sativum) and composite (Sinapis alba). The fertilizer used to V6 stage of corn were 0 and 50 units of nitrogen. Planting of all coverages was on May 22 and its production was to begin on October 6 where the chemical fallow. The corn planting was held on December 9. In general terms, the conclusions are that the use of covers did not harm the availability of water for planting the corn crop, due to the large amount of rainfall that occurred in the fallow, which allowed a recharge of water in the soil profile. In the case of nitrogen in the soil, the covers decreased the levels of this nutrient compared to the clean fallow, especially the grasses. Finally, the highest yields of the corn crop were achieved on clean fallow with and without fertilization, also without differences with the previous one are the covers of alexandrine clover, pea and vetch, all with N fertilization. The lowest yields were obtained on grasses.

Determinación de la respuesta en productividad vegetal y animal de pasturas degradadas a diferentes estrategias de manejo

Juan Carlos Irigaray Izaguirre — 2022-11-08

The present work was carried out at the Experimental Station “Dr Mario A. Cassinoni” (University of the Republic. Faculty of Agronomy, Paysandú, Uruguay). It was carried on the field paddock n° 33 (Latitude 32º 22’30,98” y Longitude 58º 03’46,00”) during the period April 15 to December 28, 2021. The main objective of the work consisted in evaluating the effect of the incorporation of Lolium multiflorum and Trifolium pratense by intercropping with different fertilization strategies and chemical control and the effects on forage production, botanical composition and meat production. The experiment was performed on an old meadow initially composed by Festuca arundinacea, Trifolium pratense and Lotus corniculatus. It consisted of 4 treatments with different strategies of fertilization and chemical control that allowed to evaluate and quantify de variables mentioned previously. The experiment used randomized complete block design (RCBD), the experimental area was divided in 3 blocks and each block divided in 4 plots equally and they were assigned the treatments randomly. The grazing management was rotative determining periods of occupation and rest depending on the height of the pasture. At the spring the entry of the animals on the plots was with a maximum of 20 cm and the exit with maximum of 7 cm. They were used 20 steers Hereford-Angus cross of 300 kg live weight average at the start of the grazing. There were used 5 animals per treatment. Climatologically in the winter the precipitations were similar to the historical average but temperatures were a bit lower than usual, this caused delay in the entry of the animals. In spring rains occurred much more isolated with an accentuated drought in December and temperatures higher than normal. This impacted on the potential of the production of the pastures and probably on animal production. In terms of the results of the work there were differences in forage production and proportion of species of interest in favor of fertilized treatments while meat production had not significant differences between treatments.

Estudio de las pérdidas reproductivas en la cría en campo natural

Alejandro Hounie Hughes — 2022-11-03

In the present work, the reproductive losses in the stages corresponding to pregnancy, calving and weaning are described through their indicators (% of pregnancy, % of calving and % of weaning), of the breeding herds of the experimental station of the Faculty of Agronomy EEBR. For this season the system is full cycle breeding in the natural field and using different genotypes (HH, AA, and their crosses) for both cows and bulls. Records of 12 years (1994-2006) were used with a total number of 1106 cows and 83 bulls. Evaluating reproductive losses, the study reveals that on average during the series of years evaluated the highest percentages of losses occurred in pregnancy and weaning, being on average 12.67% and 10.56% respectively and higher in crosses than in pure. When the experimental herds were compared with the DIEA data, it could be observed that for pregnancy the losses are significantly lower than in the commercial rodeos provided by the DIEA. On the other hand, for childbirth and weaning, the losses in these stages are similar to those provided by the bibliographic data in similar studies. As for the bulls, the ones that produced the highest percentages of loss were the HA bulls for the pregnancy and weaning stage and the AH bulls in the pregnancy stage.

Efecto del método de pastoreo sobre la producción y composición de leche y desaparición de la pastura

Lucía Fernández Long — 2022-10-20

The experiments were carried out from May 23 to June 11, from October 8 to October 25, from November 18 to December 7, 2019, at the M.A. Cassinoni, Faculty of Agronomy, Paysandú, Uruguay. The objective of this study was to compare two grazing methods (daily vs. weekly interval) and record if they influenced the performance and behavior of the dairy cow, and the rate of pasture disappearance throughout the days. To achieve this, 10 Holstein cows were used in each experiment. On the one hand, 5 cows corresponded to the weekly treatment and the remaining 5 to the daily treatment. In experiment 1, the cows accessed the pasture only in the morning shift and received supplementation. In contrast, in experiments 2 and 3, the cows were exclusively under grazing in the morning and afternoon shifts. The methods differed in the frequency of allocation of the plot, the weekly slot corresponded to 1 plot of 7 days and the daily slot 7 plots of 1 day of occupation. When the data analysis was carried out, it can be concluded that both treatments did not present differences in terms of milk production and composition. In the 3 experiments there were no significant differences (P>0.05) for height of entry and exit of the plot when comparing daily treatment with weekly. In experiment 1, the average inlet height was 16.3 ±1.04 cm and 10.6 ±0.23 cm for outlet. For experiment 2 it was 17.6 ±0.95 cm at the entrance and 11.9 ±0.83 cm at the exit. For experiment 3 it was 28.1 ± 0.89 cm and 16.3 ± 1.37 cm for outlet. When analyzed to compare the milk production of both grazing methods, no significant differences were found (P>0.05) for milk production (L/day). In experiment 1, productions of 27.0 ±2.38 L/day were obtained. In the second experiment it was 20.8 ± 0.69 L/day. Finally, in experiment 3 the values were 14.7 ±0.66 L/day. The time dedicated to grazing was 196, 535 and 592 min/cow/day for experiment 1, 2 and 3, respectively. Therefore, there were no significant differences (P>0.05). Regarding the number of grazing sessions performed by the cows, they performed 3 sessions in experiment 1 where they only grazed one shift a day, and 7-8 sessions in experiments 2 and 3 where they grazed double shift. As we have been able to verify, the daily treatment and the weekly treatment do not present significant differences in terms of production and composition of daily milk per cow. In addition, it was not possible to record differences in the behavior of the animals and in the disappearance of the pasture throughout the days in each experiment.

Estructura de parches y dinámica de utilización en campo natural y mejoramientos bajo pastoreo rotativo

Martin Pieroni — 2022-10-14

This study was carried out between November 3 and December 14, 2020, at Estación Experimental Mario A. Cassinoni (EEMAC), in the department of Paysandú, Uruguay. The same was carried out in paddock 18, on San Manuel unit soil. Two treatments were studied: natural pasture and enhanced natural pasture (8 kg/ha of Trifolium pratense cv. Estanzuela 116 and 6 kg/ha of Lotus Tenuis cv Matrero, carried out in 2018). In these treatments, 3 heifers of 290 kg average per plot grazed for 15 days, with 45 days of rest (rotary grazing). The results at a comparative level between treatments did not show differences in height, forage mass, forage supply or growth rate. Also, within each plot of each treatment, plant communities were chosen (according to soil type or botanical composition) trying to represent approximately 80% of the plot, in order to analyze how these communities behaved in their pasture structure. Inside the enhanced natural pasture, two communities were chosen, called: Solonetz soild of enhanced natural pasture and legume. Inside the natural pasture three communities called: quadrifarium, deep and Solonetz soil of natural pasture. For them, measurements of maximum height, leaf height, pod height, green/dry estimation and leaf/pod estimation were made. Also, per day of measurement, two cuts were made, separating between dry rest, leaf, pod and legumes. When analyzing by community, significant differences were obtained in centimeters and kilograms between communities and within communities (difference in the different 4 moments measured). It was observed that solonetz community were not consumed at any time and that the quadrifarium, deep and legume communities were highly selected by the animals. It was also possible to determine a large significant difference between legume communities with a high percentage of Desmodium incanum and others with a high percentage of Trifolium pratense. Also, it was obtained for all the communities, that from the third moment (day ten), the consumption by the cattle is notoriously lowered.

Reforestación de Eucalyptus sp. en Río Negro

Emanuel Benitez de Leon — 2022-09-16

The project represents a pre-feasibility study for a forestry system made up of Eucalyptus grandis and Eucalyptus dunnii. The work was proposed to be carried out on the coast of Uruguay, in the department of Rio Negro. The property is located two kilometers from the town of Algorta, where there are many companies dedicated to afforestation, which ensures good availability and quality of services. A plot of 1,993 hectares was chosen, of which 1,295 are effectively planted. The soils present on the plot are 9.3, 9.1, and 10.15. Both species are planted due to the frost resistance of Eucalyptus dunnii. The destination of the production will be the cellulose pulp market due to the logistical location of the property, which averages a distance of 140 kilometers from both UPM plants. After making the financial analysis of the proposal, it was concluded that the most relevant costs are those of the value of the property and the plantation. Within the income, the price and volume of wood are the most important. From the results of this financial analysis, an IRR of 10.9% was obtained, which far exceeds the stated objective of 7%. Although the results are positive, the investor must secure the sale price through a contract to reduce risks. Because it will be an isolated producer and it may be difficult for it to obtain good prices if it waits until the end of the cycle to look for a buyer.

Estudio del contenido de carbono orgánico del suelo en sistemas ganaderos con diferentes intensidades de pastoreo en campo natural

Federica Ramos — 2022-09-09

The objective of this work was to determine if there were differences in the SOC content, in sites subjected to different grazing intensities, on natural grasslands, and to determine, for the sites on which there was a structure of heterogeneous patches (high and low), if there were significant differences in the SOC stock between them. To achieve these objectives, two experiments were proposed within the work: analysis between sites (experiment 1) and analysis between patches (experiment 2). The experimental design used in both experiments was a DCA without repetitions, in four locations. For experiment 1, the treatments were proposed based on the grazing intensity, one treatment corresponding to grazing intensity “MA” (OF from 4 to 7% or a height greater than 5 cm on average; 1500 kg DM/ha) and the other to the grazing intensity “MB” (OF from 2 to 3% or a height of 4 cm on average; 1200 kg DM/ha). For experiment 2, the treatments were proposed based on the patches: high patches (15.6 cm average height) and low patches (4.3 cm average height). For both experiments, samples from 0 to 70 cm were obtained for the general characterization of each site and for the survey of C% and N%, and samples up to 30 cm deep were obtained for Dap, allowing the calculation of the C and N stock up to that depth. In a laboratory phase after the extraction of the samples, the physical fractionation of the SOM was carried out up to a depth of 30 cm and the percentage content of C and N was surveyed for all the extracted samples. The variables analysed were percentage of C and N, DAp (Mg/m3), stock of C and N (Mg) by fraction and total, and C:N ratio. The statistical package RStudio was used, using the "lmr" function within said statistical package. The general results for experiment 1 were that no significant differences were found between farms for any of the variables evaluated, but differences were found for some of these variables in depth. In experiment 2, significant differences were found between patches for the variables %C and Stock C in MOP, also finding significant differences for several of the variables studied in depth. From the work it can be concluded that the management of grazing intensity at farm scale to generate heterogeneity with high and low patches, generates significant in COS content between patches.

Efecto de la sustitución de monensina sódica por aceites esenciales o levaduras sobre la performance de terneros destetados precozmente y alimentados a corral con dietas concentradas

Juan Martin Suanes Telechea — 2022-09-07

The work was carried out between January 2 and March 12, 2021 in the pens of the Unidad de Producción intensiva de Carne, located at the Mario A. Cassinoni Experimental Station, located in the department of Paysandú, on Km. 363 of National Route No. 3. The objective was to evaluate the potential use of essential oils and yeasts as substitutes for monensin sodium, in feedlot diets for early weaned calves, evaluating performance, conversion efficiency, pH, consumption rates and patterns, respiratory frequencies and growth. Twenty-four Hereford calves born in the spring of 2020 from the EEMAC experimental herd, early weaned with an average age of 69 +/- 12 days and weaning weight of 80.1 +/- 10.1 kg, were used. The animals were randomly assigned to 24 individual pens with the following treatments: 1) Control: Ad libitum feeding of the RTM diet + 0.5 grams of a 20% monensin sodium source; 2) Essential oils: Ad libitum feeding of the RTM diet + 0.7 grams of an essential oil source; 3) Celmanax: Ad libitum feeding of the RTM diet + 1 gram of a yeast source. Each treatment consisted of 8 replicates (n=8 pens, 1 calf/pen), each animal constituting one experimental unit. In none of the variables analyzed were there significant differences between the control treatment and the alternative treatments. This could indicate that both essential oils and yeast (Celmanax) have the potential to replace monensin sodium as a nutritional additive in rations for early weaning.

Efectos del incremento de carga en variables bio-económicas en sistemas de producción de leche

Diego Custodio Prados — 2022-09-06

This work analyzed the effect of two stocking rates above the national average (1.5 VO/ha and 2.0 VO/ha) on: (i) forage production and harvest; (ii) grazing and supplementation times; (iii) per cow and per hectare milk production; (iv) margin over feeding costs. For forage production and harvest a model of total randomized design was used to analyze the results, using both stocking rates as treatments and paddocks as experimental units. For grazing and supplementation times, and for milk production a total randomized blocks was used with stocking rate as treatment and two blocks were repetitions were located. The experiment was conducted on the Centro Regional Sur (Camino Folle km 35.500, Canelones; Lat. - 34.613 Long. - 56.218), experimental field of the Faculty of Agronomy of the University of the Republic. The experiment took place between 1^st march to 20 of december of 2017. 56 ha and 96 milking cows were utilized, distributed in 4 grazing platforms over which 4 groups of 24 cows each were located. There was no effect of increasing stocking rate over forage production and harvest. Forage management and supplementation levels utilized were probably the responsible factors on these results. There was no effect of stocking rate on individual milk production, but there was a significant increase in milk and milk solids production per hectare with increasing stocking rate. These results turn increasing stocking rate very tempting as a strategy to increase farms productivity and income. Never the less, it must be considered that such balance in per cow milk production through stocking rate was possible by a significant increase of supplementation, which implicates an increase in feeding costs as well as infrastructure for supplements management. From the economic point of view there was no difference between treatments in the daily margin over feeding cost per cow, but there was a significant increase in the margin over feeding cost per hectare when increasing stocking rate. These means that there was an improvement in the income of the system when increasing stocking rate for these work.

Evaluación de la calidad de la canal y de la carne de las razas ovinas Corriedale, Corriedale pro, Merino Dohne, Highlander, y cruza Corriedale x Merino australiano

Alberto Martin Peraza Cappai — 2022-08-19

The research derives from the importance of evaluating the different breeds most exploited in the country and thus obtain significant information from a study that will have multiple repetitions. The general objective that arises is to compare the performance of different breeds on carcass characteristics and meat quality under the same feeding conditions. The study was carried out in the Meat Quality Laboratory of the Experimental Station «Dr. Mario A. Cassinoni» (EEMAC) of the Faculty of Agronomy of the University of the Republic (Paysandú, Uruguay: 32, 5º south latitude and 58º west longitude) and in the Casa Blanca meat processing plant, where the work will be carried out, located on the coast of the Uruguay River, 17 kilometers from the city of Paysandú in the town of Casa Blanca. Dual purpose breeds of lambs were used; Corriedale, Merino Dohne, Corriedale x Australian Merino, as well as prolific breeds in development such as the Corriedale Pro and Highlander. Management and feeding received throughout the experimental period was the same for all genotypes. A minimum of 11 male lambs per genotype were used to obtain representative results. In summary, it can be deduced that these significant differences can only be seen for carcass quality variables such as live weight (kg), hot carcass weight (kg), yield (%), compactness index, leg perimeter (cm), Leg length (cm) and PH, but not for GR point (mm), carcass length (cm) and for the meat quality variables: Color (l, a, b), CRA ( %), texture (kgf), PPC (%) and intramuscular fat (%). Of the 5 breeds evaluated, it can be said that the one that stands out the most over the rest for the following variables: live weight, hot carcass weight, yield and compactness index was the Highlander breed.

Comportamiento agronómico de variedades de promisorias de Vitis vinífera L. y de variedades "PIWI" resistentes a Mildiu y Oidio, en el sur de Uruguay

Bruno Anthony Baietto Diaz — 2022-08-19

The production of grape is one of the most demanding agronomics activities in the aplication of funguicide. With the goal of dismish the utilization of those in Europe they developed hybrids herbage of vine to fungic diseases named PIWI, with strong ascendancy to Vitis vinífera. In this job it was evaluated the agronomic behaviour of eight of them, Fleurtai, Sauvignon Kretos, Sauvignon Nepis, Sauvignon Rytos, Soreli, Cabernet Volos, Julius, UD 72-096. Besides, it was evaluated the varieties already introduced in the national vineyard and promising european varieties with the objective of intoduce them in the national viticulture. The essays are found in the zone of Canelones, Uruguay in a property that belongs to the experimental camp of INIA of Witches, during the harvest of 2019-2020. In the investigation it was made a phenological tracing per week of all the varieties, by way of use it as a reference with the phenological development of the varieties already introduced and studied in our country. It was also analyzed the composition of Berry, vigor and level of incidence and severity to diseases in the variants indicated as resistents, in witch monitoring was done per week. The results obtained in this job pretend to made an approach to the agronomic behaviour of the promissory varieties to the weather conditions of our country and not achieve definitve conclusions since it was about herbage in the second year of growing. The results obtained allowed to obtain an approach in the phenological development of the promisory variants, which are found in 3 differentiated groups, obtaining a phenological development of Julius and Fleuratai varieties similar to the Tannat variety. The monitoring in the varieties indicated as resistan to the Plasmospara vitícola disease obtained a resulto f 0% in incidence and severity of the leaf.

Manejo de Amaranthus spp. en praderas de Festuca arundinacea y Trifolium pratense

Jose Antonio Fernandez Bonino — 2022-08-12

The agricultural-livestock production systems of Uruguay are characterized by rotating winter and summer agricultural cycles, with cultivated grasslands. Red clover (TR) (Trifolium pratense) and fescue (Festuca arundinacea) are two of the most used forages. The alternation between crops and pastures generates benefits in the use of resources and improves the sustainability of the system. In recent years it has become considerably more difficult to control the Amaranthus hybridus, A. palmeri and A. tuberculatus (yuyos colorados, YC) that coexist in the farms. The objective of the work was to evaluate the control of YC with pre- and post-emergent herbicides and the selectivity of these on already established TR and fescue. A trial for each forage species was carried out in the field between December 2019 and March 2020 in the town of Palmitas, Soriano, Uruguay. The treatments tested in RT were: diflufenican, s-metolachlor, diflufenican+s-metolachlor, flumetsulam, 2,4-db and MCPA. And in fescue they were: diclosulam, diflufenican, s-metolachlor, metribuzin, fluroxypyr+halauxifen, 2,4-d, picloram, fluroxypyr and MCPA+clopyralid. The same treatments were tested individually for each YC species (A. hybridus; A. palmeri and A. tuberculatus) under greenhouse conditions at INIA La Estanzuela, Colonia, Uruguay; in pre-emergence (pots planted with 30 YC seeds) or post-emergence (plants with 4 true leaves). The doses of the herbicides and their use as pre or post-emergents followed the label recommendation, and in all the trials 4 repetitions per treatment and a control without application were used. The field trials did not present the expected YC infestation, and only the phytotoxicity of herbicides on forage plants could be evaluated. TR presented approximately 25% phytotoxicity 30 days after the application of 2.4 db and MCPA, while the other herbicides did not exceed 15% phytotoxicity. For fescue only 2,4-D, picloram and fluroxypyr showed significant phytotoxicity, with values not higher than 20%. In greenhouse trials with pre-emergent herbicides, only diclosulam and flumetsulam will allow YC to germinate. The most effective post-emergents were the hormonal ones with controls greater than 85%, with the exception of MCPA, which did not exceed 62%. The post-emergent herbicide diclosulam was not effective in controlling YC. There are still control options for these YC populations in TR and fescue, but management must be extreme in order not to aggravate existing resistance problems.

Evaluación de metatopolina en micropropagación de genotipos de eucalyptus globulus

Facundo Esquivel — 2022-08-12

The objective of this thesis was to evaluate the effect of two cytokinins in Eucalyptus globulus individuals in the micropropagation process, focusing on the multiplication and rooting phases. For the multiplication phase, the study evaluated shoot proliferation, height growth, callus production and vitrification in explants, while in the rooting phase the study focused on determining rooting percentages and root length. Four genotypes and five treatments were used for the experiment, depending on the type and concentration of cytokinin supplied in the multiplication phase.

In the multiplication phase, the explants were subcultured every four weeks for a period of 3 months. The results indicated that the supply of cytokinins is necessary in the multiplication phase, since without, are obtained small explants, with low proliferation and with a high incidence of calluses in leaves and apex. The explants from Mt1 treatments turned out to be superior in height, as it was the only treatment that differed from the control for the three height intervals studied. Comparatively, the explants obtained from Ba1 resulted in a lower height than the Mt1 explants.

To evaluate the variables of the rooting phase, the explants were transferred to rooting media for three weeks. The results showed that treatment without cytokinin registered low rooting percentages (6,3%), due to poor explant conformation in the multiplication phase. The treatment with Mt1 obtained the highest rooting percentages (39,0%) and root length, and the 19G40 genotype presented the highest rooting percentages (45,8%), being the only genotype that rooted in all treatments. In turn, the 19G40-Mt1 combination presented the highest rooting percentage, 93%.

Posparto y amamantamiento en ovejas

Rodrigo Dematté Olivera — 2022-08-08

The sheep sector in the country has been undergoing transformations, the most notable of which is production specialization, with the production of fine and super fine wool located mainly in the north of the country. On the other hand, producers with flocks of medium and thick wool, saw difficulties in selling for several harvests, accompanied by attractive values in the price of meat, found themselves in the need to look for new alternatives to increase income. This is how the production of heavy lamb for export emerged, and the production of sheep meat as an attractive item for the sector. For this productive option, obtaining a greater number of lambs per year, and the search for tools that promote an increase in the reproductive results of the flocks, seems to be a priority. Having followed a technological path that, among other things, decreased the perinatal mortality of lambs and increased the prolificacy of flocks, some researchers in the country have focused their interest on accelerating the interval between calving, although they have found limitations in reproductive results when serving ewes giving birth and suckling. This experiment compares the reproductive results of synchronization and subsequent resynchronization of oestrus and ovulation using fixed-time artificial insemination (FTAI) in the reproductive season of multiparous ewes calving in early autumn and suckling (PAR group), with that of multiparous ewes that calved in spring and had been weaned 3 months earlier (Group CON). In general terms, the PAR group ewes had a worse performance, mainly in synchronization and first IATF than those of the CON group. They had a lower (P ≤ 0.05) presentation of estrus (39.4%), percentage of ewes that at 17 days presented a vascularized corpus luteum indicator of early pregnancy (21.2%), and at 42 days none of them was diagnosed pregnant. In comparison to the CON group in which 71.7% of ewes were observed to be in heat and a pregnancy at 42 days of almost 60% of the ewes. However, at resynchronization and second FTAI, no differences were observed in the percentage of oestrus between groups (62.5% and 65.2% PAR and CON groups, respectively), and although at 42 days a tendency was found for pregnancy percentage was lower in PAR ewes than in CON ewes (20.8% vs 43.4%; P = 0.06), the percentage of lambing was not different between groups (20.8% and 34.7 %, PAR and CON group, respectively). As a result of both FTAI, calving results were higher in the CON group than in the PAR group (71.7% vs 15.1%; P = 0.005). Based on the results obtained, it is concluded that the technique used is not recommended in ewes 30 days postpartum and nursing a lamb.

Evaluacion del efecto de la “malla sanitaria” sobre el control de la sarna del manzano causada por Venturia inaequalis

Diego Andrade Gatto — 2022-07-29

Apple is the most important deciduous fruit crop in Uruguay. Apple scab caused by the fungus Venturia inaequalis is the main crop disease. Its control is based on chemical aplications, and up to 12 applications can be made each season. The main pest insects affecting this crop are carpocapsa (Cydia pomonella) and the native leafrollers, Argyrotaenia sphaleropa and Bonagota salubricola (Lepidoptera: Tortricidae). Numerous sprays with insecticides are carried out to control them. Consumers are increasingly demanding in terms of the safety of the fruit, both chemical and microbiological. In order to respond to these demands, a regional insect control program has been implemented based on sexual confusion by pheromones, thus reducing the use of insecticides. Recently, and for the same purpose, the use of exclusion meshes as a pest control method in apple trees was introduced for the first time in Uruguay. As a secondary result of the use of the insect mesh system, an apparent reduction in the incidence and severity of Apple Scab has been observed. If this is verified, the anti-insect meshes would contribute to minimize fungicides sprays to control V. inaequalis. To evaluate whether the use of insect exclusion nets contribute to reduce the incidence and severity of apple scab, a field trial was carried out on a Red Delicious apple orchard. Treatments were absolute control without any application of fungicides, Alt´Carpo exclusion net in a single-row netting systems and control where scab was controlled by periodic applications of fungicides. Each treatment was applied to groups of three rows of 25 plants. After three periods of infection, the incidence and severity of scab in leaves and the incidence in fruits were evaluated. In order to determine if the reduction in the incidence and severity of scabies caused by sanitary nest is due to the fact that it prevents the arrival of V. inaequalis ascospores to susceptible tissues, the concentration of ascospores inside and outside the mesh was quantified using Burkard volumetric spore traps. Results showed that the sanitary mesh significantly reduced the incidence and severity of scab on leaves and fruits. Under the mesh, the concentration of ascospores was significantly lower, which would explain the lower incidence of the disease. Reducing the incidence and severity of apple scab on trees covered by the mesh is not enough to eliminate fungicide applications directed at V. inaequalis control.

Variabilidad inter poblacional en características asociadas a la capacidad de resiembra natural de raigrás

Nicolás Rodríguez — 2022-07-28

The study of variability in the viability and dormancy of ryegrass seeds (Lolium multiflorum var. Lam) would allow to know which genotype is best suited to different production systems. Ryegrass is an annual winter grass being one of the main species used for animal feed during the winter. It is chosen for its high forage production and good natural reseeding. Cultivars may have differences in traits associated with reseeding ability, including seed production and seed persistence in the soil. The seed persistence is achieved by maintaining dormancy and viability through summer. There are no previous reports in our country about cultivar differences regarding these traits, but regional and foreign information indicate that seed viability decreases with time lasting no more than two years in the soil, while dormancy disappears after 150 days of dispersion. The objective of this work was to evaluate the genetic variability in ryegrass in seed production, viability and dormancy in dry storage conditions and in the field. The effect of ploidy level was considered as a possible additional factor in variations of the parameters studied. The methodology consisted in the evaluation of seed production of 9 varieties of ryegrass (4 diploids and 5 tetraploids), estimating the seed yield components to know which was the best predictor of yield. The harvested seeds were used for two experiments, one was germination at 25ºC and 30ºC to evaluate dormancy and viability in three dry storage times (0, 39 and 67 days). In the other experiment the seeds of two contrasting genotypes (E284 and INIA Camaro) were buried in the soil to measure field germination, dormancy and viability every 30 days for approximately three months. There were differences between the genotypes for seed production, the most prominent being LExp2, Cambará and E284, with the number of seeds per spike being the characteristic best associated with seed production. As for the dormancy in dry storage there were differential behaviors in the dormancy and its evolution over time, allowing to group cultivars that quickly descend the dormancy within a month (p.j, E284) and others that took more time to descent (p.j, Bakarat) after two months. In the field there were differences in behavior, with interesting interactions observed, in which INIA Camaro maintained seed viability and seeds ready to germinate for a longer time than E284, showing a better persistence of the seed bank in the conditions of this experiment. Finally, it is concluded that there are differences in characteristics associated with the ability to reestablish and that these differences are better explained by the variation between cultivars than between ploidy levels and that there may be a group of cultivars that are better adapted than others to systems that include natural reseeding, depending on the environment and the management that is carried out. It is noteworthy that this species does not generate a persistent seed bank in the soil since the seeds at the end of the experiment, either germinated or lost viability.

Productividad primavero estival de campo natural, campo natural mejorado con leguminosas y fósforo o fertilizado con nitrógeno y fósforo

Lucas Fernández Ferro — 2022-07-22

The experiments were carried out at the Mario A. Cassinoni Experimental Station of the “Facultad de Agronomía – UdelaR” located on 363^rd km of the “General Artigas” route, Paysandú, Uruguay; precisely 10,3 ha being part of stockyard 18. The evaluation period was from september 17^th of 2020, to march 5^th of 2021. This period was divided into three sub-periods: Spring (17/9/20 – 14/11/20), Spring-Summer (14/11/20 – 10/1/21); and Summer (10/1/21 – 5/3/21). The objective was to evaluate the productive response from Sping to Summer of the natural field with different levels of intensification, the introduction of legumes with phosphorus fertilization or two dosage of nitrogen fertilization and phosphorus fertilization, under rotational grazing by a forage offered of 10-12%. The experiment design used for experiment 1 was completely randomized blocks with four repetitions. The treatments were: without intervention (CN), an improvement with Lotus tenuis and Trifolium pratense (CNM), and two levels of nitrogen fertilization, 60 kgN/ha/y (N60), and 120 kgN/ha/y (N120) applied in autumn-winter. Besides, except the control treatment (CN) all the others were fertilized with phosphorus by 40 kgP2O5/ha/y in autumn. Otherwise, the experimental design used for experiment 2 was also completely randomized blocks with four repetitions, save that in this time the treatments were two levels of nitrogen fertilization: 60 kgN/ha/y and 120 kgN/ha/y applied in autumn-winter; both under phosphate fertilization once a year by 40 kgP2O5/ha in autumn. In this experiment, the effect of the fertilization history was also evaluated. The analyzed variables were: present forage, forage production, daily growth rate, available forage, remaining forage, available and remaining height, disappeared forage, botanical composition, relation between green forage and dry forage of available and remaining forage, percentage of bare ground, ground covered by mulch, and ground covered by dirty field weeds, live weight, stocking rate, average daily gain, gain per hectare, and forage allowance. As a result of experiment 1, it was observed that the N120 treatment was able to increase the forage production in comparison with CN and CNM, without showing significant differences with 60N treatment. Regarding the secondary production, no statistically significant differences were detected between the treatments for the total period in the average daily gain of the animals. However, the intervention of the natural field, either with the addition of legumes or the nitrogenous fertilization, provided the animals with higher quality forage, because even though they had lower forage offer (OF) they obtained statistically non-different gains. Both the addition of legumes and nitrogen generated a change in the botanical composition. For the total period evaluated, Lolium multiflorum was significantly higher in the CNM, N60 and N120 treatments, on the other hand, Paspalum dilatatum presented a significantly higher contribution in the CNM treatment compared to N120, without denoting significant differences with the CN and N60 treatments. As a result of experiment 2, it was obtained that the longer fertilization history generated a lower spring-summer forage production, in response to the substitution of summer perennial grasses (Paspalum dilatatum and Paspalum notatum) by dwarf weeds and MCS.

Caracterización fenotípica de frutos de "Guayabo del País" (Acca sellowiana (Berg) Burret), en dos poblaciones de hermanos completos

Gustavo Rostagnol long — 2022-07-21

The feijoa or “Guayabo del país” [Acca sellowiana (Berg.) Burret] is a promising native fruit tree, due to the outstanding nutritional properties of its fruits. This fruit tree is extensively cultivated in Colombia, New Zealand and the United States, while in Uruguay it is cultivated only on a small and local scale. Currently, the main objective of the Breeding Program of Guayabo del país in Uruguay (FAGRO-INIA) is to develop and improve superior cultivars, with excellent fruit quality. Supporting this program, in this study fruits of two breeding populations were evaluated with the objective to characterize the phenotypic variation. Additionally, two selection indexes were compared and applied to select individuals with superior fruit characteristics. Two full-sib F1 populations, H5 (139 individuals) and H6 (182 individuals), connected by one common progenitor were characterized. Fourteen morphological variables were evaluated during three years (2015, 2016, 2017) including: fruit diameter, fruit length, diameter-length ratio, fruit weight, pulp weight, skin thickness, total soluble solids, total titratable acidity, 100 seeds weights and flowering date; in addition to the qualitative descriptors: roughness of the skin, pulp oxidation rate y shape of fruit base. For each population, a descriptive analysis was carried out for each variable, the degree of variability between years and populations, as well as the correlation between variables. To meet the breeding objectives, superior individuals were identified through the multiplicative index and the sum of classification index. Both populations presented a high degree of phenotypic variability, consistent between the three years of evaluation. The most high and positive correlations among fruit quality traits were obtained between fruit size (diameter and length) and weight (fruit weight and pulp weight) for both populations. Heritability estimates were moderate to high for all variables analyzed, and similar for both populations except for total soluble solids. A high correlation between the selection index was found (0.79 and 0.80, for H5 and H6 respectively), indicating that the ranking of individuals was well preserved. Thus, 8 and 11 individuals for H5 and H6, respectively, were selected for their remarkable fruit quality. The large phenotypic diversity reported in these breeding populations and the identification of superior genotypes based on multiple fruit traits, represents a valuable contribution for the breeding efforts in A. sellowiana.

Gestión espacial y temporal de la intensidad de pastoreo y su relación con los resultados productivos y económicos

Estefani Camacho Hamilto — 2022-07-19

Family livestock systems on natural grasslands in Uruguay are socially, economically and environmentally relevant. The absence of spatial and temporal grazing management throughout the year on the farms impacts the reproductive, productive and economic results. This study aimed to analyse the relationship between grazing intensity, grazing management practices and productive and economic indicators. We used a systemic approach and the case study as a research methodology. This approach allowed describing the management practices implemented by the systems, quantifying the spatial and temporal distribution of grazing intensity based on forage height, and identifying how grazing intensity is related to the results obtained. It was identified that the best reproductive and economic results are related to the systems categorized as managers. All livestock systems have ample room to improve productive y economic results by managing grazing intensity at time and space.

Frecuencia e intensidad de defoliación de Paspalum dilatatum Poiret y Paspalum quadrifarium Lamarck en campo natural y campo natural mejorado

María Fernanda Platero Stirling — 2022-07-12

The present essay aims to study the response in frequency and intensity of defoliation of Paspalum dilatatum Poiret and Paspalum quadrifarium Lamarck in natural rangelands and enhanced rangelands. In order to this, the morphogenetic characteristics and the response to defoliation of the mentioned species were evaluated. The study was carried out on the Experimental Station Mario A. Cassinoni from Faculty of Agronomy in Paysandú, coordinates 32º23’21,10” south latitude; 58º01’55,24” west longitude, on Brunosols typical Soils, belonging to San Manuel unit, which is developed over lodolites from Fray Bentos formation, during the period October 30^th to December 14^th of 2020. The experimental design consisted of randomized complete block design with three replicates. The treatments evaluated were natural grasslands and enhanced natural grasslands with 8 kg/ha of Trifolium pratense E116 and 6 kg/ha of Lotus tenuis Matrero with an application of 40 kg/ha de P₂O₅. Measurements were made on 30 tillers per plot, of the length (green portion) of the leaf and leaves were characterized weather they were in extension, completely extended, defoliated or senescent. These determinations on the marked tillers were made every two days on average, with a total duration of 15 days per block. Grazing pattern was expected to differ between species and also to be modified with the different treatments and during the grazing days. The obtained results showed that P. dilatatum had a greater number of leaves per tiller and P. quadrifarium presented a higher extension rate and leaf blade size, characteristics that where not modified through the different treatments. Grazing pattern, expressed through frequency and intensity of defoliation, differed between P. dilatatum, which was more intensely grazed, and P. quadrifarium, which was more frequently defoliated. The amount of grazing days did not modify frequency and intensity of defoliation during the grazing period, despite the reduction of forage allowance.

Caracterización anatómica de la madera de Eucalyptus grandis proveniente del este uruguayo

Daniela Verocay Da Silva — 2022-07-12

In the Uruguayan forestry industry, the main product is bleached chemical sulphate pulp, with Eucalyptus grandis being the second most planted species. The general objective of this work is to verify the pulpable characteristics of Eucalyptus grandis from a plantation in eastern Uruguay. Among the specific objectives is to determine the basic density of wood and its anatomical properties; analyze the effect of the height and the radial position in the trunk of the specimens on the density and anatomical characteristics; calculate pulp and paper quality indices; relate the indices to those recommended for pulp and paper production. The study included 10 11-year-old trees belonging to the company Redalco S. A., the logs used were obtained at two heights: 1.30 and 2 meters (DAP and API, respectively). Libriform fibers were found, where the variables to be measured were length, width, lumen diameter, fiber area and wall thickness. Regarding the two heights, no significant differences were found, however, there were significant differences for the radial positions in the diameter of the lumen and fiber area, in the interaction height x position the differences were in the length and width of the fiber. The woody vessels were arranged solitary, with a diffuse porosity, in the radial position the differences were in the tangential diameter and frequency, while in the height x position interaction they were in area and vessel length. The rays were mostly uniseriate and homogeneous; the average for the frequency in linear mm was 13.94, the height 193.96 µm and 9.51 cells. There were no significant differences in height, radial position, or in the height x position interaction. The density presented an average of 0.381 g.cm-3, a standard deviation of 0.03 and the coefficient of variation was 7.87%. For the Anova analysis, only differences were seen for the radial positions, especially in position A. Coefficients for pulp and paper production were calculated, Runkel Index 0.28, Flexibility Coefficient 0.54, Stiffness Coefficient 43 .01,Wall fraction 15, 43% and Luca Factor 0.542. With the results obtained in the production of pulp and paper with Eucalyptus grandis from the east of the country, they present a pulp with good formation, with paper resistance in relation to traction and bursting.

Evaluación de híbridos experimentales de tomate resistentes a hongos foliares

Federico Supparo Teixeira — 2022-07-04

Tomato is the second most important vegetable in terms of production both worldwide and in Uruguay. There are several pathogens damaging tomato crops, including foliar fungi. To reduce this problem in many systems, chemical control is used with synthetic phytosanitary products, with negative effects both for the environment and for the operators who handle these substances, as well as product safety problems. For this reason, the use of tomato cultivars with genetic resistance is an interesting tool that allows to reduce these impacts, in addition to facilitate crop management, reducing production costs and allowing the implementation of biological control strategies. Today, few cultivars have resistance to the three main foliar fungi of tomato crop in Uruguay (Stephylium sp., Oidium neolycopersici and Passalora fulva). One of them is the experimental hybrid of INIA, HT117. This material has productive and quality limitations. The present work consists of evaluate from the productive, sanitary and fruit quality point of view, different experimental hybrids with resistance to foliar fungi (HT347, HT501, HT545, HT551, HT560),analyzing their behavior respect HT117 and two commercial cultivars as reference: ELPIDA and INIA FRONTERA. For this, a randomized block experimental design with three replications was carried out. The experimental plots were ten individual plants. Variables related to plant characteristics, production, fruit quality and disease resistance, were evaluated. Regarding plant characteristics, differences in plant vigor were observed, with hybrids with high vigor, even greater than ELPIDA (a commercial variety characterized by its high vigor), as is the case of HT501. On the other hand, same other hybrids showed low vigor, such as HT560 and HT545. The yield did not vary between materials, but there were differences in fruits number as well as in fruit size. Some hybrids were characterized by their high number and low size, such as HT347 and HT501, while others by their low number and larger size, such as HT560, HT551 and HT545. For this last group, tsize fruit uniformity must be improved. In terms of fruit quality, there is a lot of variation between experimental hybrids, standing out for color HT501and for firmness HT347 and HT545. Respect disease resistance, all the materials responded according to their previous characterization, there was only segregation for ash by HT545, HT551 and HT560, while HT501 was found segregating for cladosporiosis. All the materials have same positive particular, but none combines all the necessary ones to be a competitive commercial variety. For example, HT501 is a very complete material, but it has serious limitations in terms of fruit size and loss of firmness. For HT545, HT551 and HT560, although they have a very good size, have limitations in terms of commercial quality and low plant vigor. HT347 has very good firmness, but has no resistance to Passalora fulva and has medium resistance to Stemphylium sp. In addition, it has small fruit size. It is confirmed that the three pathogens affect tomato crop under the same environment, which is why they bring together the 3 resistance genes, which is very positive at the productive level. New materials must continue to be investigated in order to achieve a hybrid with resistances and competitive productive characteristics.

Determinación de la precisión de nuevas tecnologías en la medición de la altura de árboles

Gaston Matias Rodriguez Carballo — 2022-07-01

Forest inventories allow us to project and to estimate wood´s volume within a rodal. Historically records have been collected esignedt the field by using conventional tools such as the Bitterlich relascope which can be used to measure tree´s heights. With the development of new tools, new mobile based applications have been esigned allowing us to measure tree´s heights on smartphones. In this vein, this paper/exercise ´s main goal has been to evaluate and to determine the best Android designed applications by comparing their results which the ones from the Bitterlich relascope. The Clinometer, Clinometer, Clinômetro Florestal, Dioptra, Globe, Measure Height, MOTI, Smart Measure, Tree-h and Trees applications were evaluated. A total of sixty (60) tress were considered which have been divided into two (2) categories; smaller trees between 5 and 15 cm and longer tress between 15 and 30 cm. All trees were selected to be heterogeneous and distributed among local parks within the city of Montevideo. Clinômetro Florestal do not present significant differences with the Bitterlich relascope for trees between 5 and 15 m, and exhibit high accuracy in all categories, which is why it is one of the most convenient to operate in the field.

Impacto productivo del acceso a sombra en la parcela de pastoreo de sorgo forrajero tendiente a mitigar el efecto del estrés por calor en novillos hereford.

Federico Kuchman Robaina — 2022-06-24

The objective of this project was to evaluate the effect that the access to shade in the plot of land has on the mitigation of heat stress and summery animal performance in steers fed with forage sorghum, with an assignation of 8% of the PV. The experiment was held in the Experimental Station Mario A. Cassinoni, Paysandú, Uruguay, between 12/1/2021 and 23/3/2021. We used thirty Hereford steers, approximately 18 months old, and with an initial weight of 347 ± 5,5 kg, which were randomly assigned to two treatments: free grazing with and without access to shade. The animals grazed on forage sorghum of the type ADV 2800, rotating weekly. Pastures were used in grazing with an average availability of 10727 ± 3637 kg DM/ha and 119 ± 39.8 cm in height. The average gain of the treatments was 0.617 kg/a./day for the animals with access to shade and 0.523 kg/a./day for those without access to shade; in this way, a significant effect of the shade on the performance of the animals was determined (P=0.02), defined by the second stage of the experimental period (0.717 vs. 0.570 kg, P=0.012), The shade improved the HLI average (67 vs. 72) notoriously improving animal performance, reduced rectal temperature (40.1 vs. 37.3 °C, P=0.0076), respiratory rate (83.3 vs. 63.2 rpm, P<.0001) and panting intensity when compared to treatments without access to shade.

Evaluación del pastoreo en franjas matutina y vespertina frente a franjas de más de un día de ocupación sobre la producción de leche de vacas holando

Ines Paredes — 2022-06-03

The objective of the present work was to study the effect in milk production and pasture production while submitted in different pasture allocations, the first treatment with daily allocations (TD) and the second treatment with 3 to 5 days allocation (TOL). The evaluation period was between October 1, 2020 and December 15, 2020, period I was from 10/1/2020 to 11/15/2020 while period II was from 11/15/2020 to 15/12/2020. The design used was a completely random design (CRD) where two treatments were compared in two periods; a daily treatment (TD) where the cows consumed the grass in semi daily plots and a long occupation treatment (TOL) where the cows consumed the same plot for 3 to 5 days. In the first period the animals grazed twice a day (morning and afternoon) while in the second period the animals grazed only in the afternoon. The diet for both treatments was the same during both periods. Each treatment consisted on an average of 270 multiparous cows that started the experiment with an average of 56 days in milk, 2.8 calvings and an average live weight of 486 kg. The variables analyzed were: milk production and composition, pastures growth rate, of dry matter intake and behavior. As a general result there were no statistically significant differences found in terms of milk production (26,4 kg/cow/d) and composition between treatments, although there were between periods, which was expected given the decrease in the milk production curve. Regarding the growth rate of the grass (64 kg DM/ha/day), no differences were found between treatments nor were there differences in behavior and intake of dry matter between the animals of both treatments. We can conclude that the difference between semi-daily plots or plots of 3 to 5 days of occupation do not present differences in terms of milk production or pasture growth, the second being an option that would benefit the farmer easing the daily management and reducing the cost of production.

Diagnostico y proyecto de las empresas ¨Don Leoncio¨ y ¨La Carito¨

Damián Aquino Corralejo — 2022-05-27

The previous property project work was presented as a final requirement of the agricultural engineering career to obtain the title of the University of the Republic. The aforementioned project was carried out in two family livestock establishments in the Sierras del Este area, located in the department of Maldonado.

In the first stage of the project, field data was collected that allowed identifying the main weaknesses and strengths of the production system and the environment, thus allowing a project proposal to be proposed that is adapted to the needs of each establishment. In the case of the Don Leoncio establishment, the division of paddocks, reform of the shed, water in the plots and a semi-enclosure system for cattle were proposed, allowing for rational use by optimizing resources. In the case of the La Carito establishment, pursuing the idea of improving the economic production indicators, the division of smaller paddocks, improvement of the natural field, reduction of sheep and improvement of cattle stock was proposed.

Once the proposal was made, the need for financing the project was evaluated, that is, to check if the establishment in question has the financial backing to be able to carry out the project or if it was necessary to resort to the credit option. In both cases it was proposed to resort to credits to finance the project.

In the last stage, a risk analysis was carried out, where different scenarios of changing prices were proposed, in order to evaluate how stable and viable the project remained in the different situations and to what extent it could be carried out. concluding that the project is consistent even with very little encouraging scenarios for production.

Efecto del sistema de cultivo sobre propiedades físicas del suelo y su relación con el rendimiento de maíz y soja

Bruno Alberto Martinez Fernández — 2022-05-25

Uruguayan farming systems have been constantly changing since the 1950s. At first, the system was basically monoculture under plow tillage where the most important cash crop was the wheat during winter. Then, the system turned into a system based on crop - pasture rotation. At the beginning this system used plow tillage, but then, in the 2000s were done with no tillage. Nowadays, the predominant farming system is based on continuous cropping with neither tillage nor pasture. Even though it is expected that this kind of farming system generate less soil loss through erosion, in order not to jeopardize soil ́s chemical and physical properties, this system must follow some requisites. Among others, managing the system in a way that the beneficial effect of the pasture (which is not included) is replicated. Within this context, appears the present study which has to main objectives: 1) To detect the effects of different no till farming systems over the soil's physical properties and soil organic carbón (SOC); 2) To quantify the response of maize and soybean crop to the changes in soil ́s properties due to the different farming systems. The study was done in a long term experiment site in Paysandú department, Uruguay, most precisely in the “Estación Experimental Mario Alberto Cassinoni” of UDELAR ́s Facultad de Agronomía. The experimental design used was randomized complete blocks design with four treatments with four repetitions each. SOC and its stratification showed significant differences among the different farming systems as well as the infiltration rate and the visual evaluation of soil structure. However, there was not a significant response of either crop in terms of yield. Significant difference was detected in the number of ears per plant in R3-R4 stage, while in soybean there were no differences in the yield components

Efecto de la aplicación de caliza y azufre en cultivo de soja

Mauro Mansilla — 2022-05-25

Soybean cultivation [Glycine max. (L.)] is currently one of the main summer crops in Uruguay. Despite this notorious increase in the sowing area, the general average yield has remained around 2000 kg/ha of grain, with temporal and spatial variations associated with management and/or environmental factors, among others. Within these, nutrient management and soil acidity stand out. The objectives of this work were: a) to study the response of the soybean crop to liming and the addition of S; and b) determine the effect of adding agricultural limestone on soil pH. The study was carried out on a Subeutric Brunosol, from the Libertad Formation, in a commercial farm. The treatments were three levels of limestone (0, 2000 and 4000 kg/ha) and three levels of S (0.12 and 24 kg/ha of S), with and without N. Calcium carbonate ( CaCO3), applied one month prior to planting, manually, broadcast on the surface, and incorporated with tillage. The doses of S and N were adjusted with ammonium sulfate and urea. Final grain yield, soil pH evolution during the crop cycle, N and S content in the plant in three phenological stages of the crop and grain S content were evaluated. There was a response in grain yield to the addition of limestone, although only up to the lowest dose of limestone (2000 kg/ha). The increase in yield due to the addition of limestone was 310 kg/ha on average (between 18 and 30% compared to the control). No response was found to the addition of S, neither in the concentration of this nutrient in the plant nor in the final yield. Possibly due to the level of sulfate in the soil, the high value of organic matter and the good mineralization conditions during crop growth. There was no limestone interaction with S. The estimated increase in soil pH was 0.17 units for each ton of limestone added and the maximum increase occurred after 62 days of limestone addition.

Proteína asociada a la gestación (PAG) en vacas lecheras Holando y Normando y su correlación con metabolitos sanguíneos y composición de la leche

Maria Gimena Machado Streccia — 2022-05-20

The aim of this study was to determine the secretion dynamics of the pregnancy-associated protein (PAG) during a biological cycle in dairy cattle Holstein Friesian (HF) and dual purpose Normande (N), in a pastoral-based dairy production system with little incidence of external supplements (SPBI). In order to better understand the relationship between circulating PAG levels and the nutritional/metabolic status of the animals, correlations were determined between PAG and energy balance data (EB), estimated net energy consumption (EC), live weight (LW), uterus weight (UW), body condition score (BCS), plasma metabolic parameters (urea, glucose, NEFA), milk yield (MY), Fat-and protein-corrected milk yield (FPCM) and milk solids composition (% protein, % fat, % lactose). Moreover, an exploratory mathematical model was established to explain the dynamics of PAG secretion throughout the biological cycle. The experiment was carried out at the Bernardo Rossengurtt Experimental Station of the Agronomy Faculty, Udelar. Twelve multiparous dairy cows, N (n = 6) and HF (n = 6) breeds were selected according to their conception date (07/15/2016 ± 13 days). Milk Yield (MY) was measured every two weeks, and once a month milk composition. Plasma PAG concentration was measured prepartum (day -11) and postpartum on days 24, 60, 161, 187, 227, 255, 279, 313 and 326, through the biological cycle.
The mean PAG concentration considering the entire study period was significantly affected by the genotype, being higher (P = 0.03) in the N genotype (9.04 ± 0.028 ng/ml) than HF (8.52 ± 0.028 ng/ml). The plasma concentration of PAG for both genotypes was adjusted to a polynomial model of degree 6. PAG presented a high and negative correlation (r=-0.67), highly significant (P- value, 4.04E-07) with the NEFAs. The % of lactose presented a medium-high, negative (r=-0.38) and significant (P=0.0044) correlation with the PAG. The PAG profiles of the present study showed that the Normando breed, which mobilizes body reserves in a short period compared to HF breed, have a better reproductive performance. In addition, in pastoral systems with seasonal fluctuations in forage supply, the concentration of PAG throughout gestation could be a good indicator of the nutritional status of the mother, which is directly related to the energy demand for growth and fetal development.

Cobertura del suelo, captura y uso de la radiación y el agua, por vicia y centeno como antecesores de soja

Juan Ahunchain Crusich — 2022-05-18

The agricultural expansion that the country went through in the first decade of the XXI century showed symptoms of its unsustainability in the long term. The frequent periods of winter fallow in the agricultural rotation demonstrated being the weakest point on these production systems. Cover crops appeared as an alternative in order to mitigate these unproductive periods and its consequent loss of physical-chemical properties of the soil. The magnitude of these effects strongly responses to the species used as cover crop and the biomass production achieved, so the objective of this thesis is to evaluate the differential performance of a grass and a legume that had been sown purely or in a mix and its residual effects on the soybean sowing. The species used were Vicia villosa and Secale cereale. Regarding the behavior of the cover crops, hairy vetch obtained a higher interception of radiation but a minor efficiency in the use of it. The mix and the rye did not show differences when talking about RUE, but since the mix achieved a higher radiation intereceptance, this cover crop overcame the other treatments referring to biomass production. They were observed differences in the weeding dynamics during the growth cycle, and also during the fallow period that occurred after the end up of their cycles. Linear regression models were adjusted for residuals nitrates levels when the sowing of soybean happened in function of the biomass production obtained by each cover crop, observing contrasting trends between treatments. The ground cover by the crop residues at the moment of the soybean sowing showed significant differences, but they did not affect the implantation of the crop.

Evaluación del tipo de sorgo en la producción de forraje bajo pastoreo

Romina Blanco Cardozo — 2022-05-10

The purpose of this essay is to evaluate the objectives which were planned to achieve in the project. They consist of measuring the quantity of dried forage using different kinds of sorghum as well as the management of the remaining pasture after cutting it. The experiment was carried out in Experimental Station Mario A. Cassinoni (EEMAC), Paysandú, Uruguay. (32º 22´ 31´´ S 58º 3´ 47´´ W), over Typical Eutric Brunosols soils. Treatments consist on: two varieties of forage sorghum: Talismán (BMR) and Green supremo (FS). Using the same procedure, the productivity of these grass, their components and their final quality were tested. For this experiment the field was divided into smaller plots with three blocks. Not significant difference was found in the dry matter (a bit higher than 0,05) during the time it was evaluated (5403 vs. 7270 kg/ha of DM). Total leaf and stem dry matter production adjusted to a lineal model with the height (cm) of the available forage, and these with remaining forage. There was a great variety in the obtained results due to environmental conditions. Lack of rain was crucial in the final results so that the management of the material was definitely more important than the kind of sorghum used in the experiment.

Efecto de diferentes peines y esquiladores sobre las lesiones de esquila en ovinos Corriedale

Eduardo Sebastián Viera Rocha — 2022-05-07

In this study, data derived from pregnancy shearing of Corriedale ewes were used. The study was done at a sheep farm in the North of Uruguay, 80 km to the east of Salto. The aim was to evaluate if the occurrence of skin lesions varies according to shearing comb, shearer skill and the zone or area of the body of the sheep. Five-hundred ewes were shorn in five different sessions (n=100), which were randomly assigned to a comb, a shearer in a Latin square design. Therefore, 20 ewes were recorded for each comb, shearer, and session of five levels each, except for the “shearer” treatment which had six levels. The most used combs in Uruguay were tested; the Standard comb, the Snow Cover (Cover) comb, the high shearing Beyuan (Chinese) comb, the R13 comb developed by the Uruguayan Wool Secretariat (SUL) and a new comb modified from the R13. A letter (A to F) was assigned to each shearer to maintain their identity private. A form was used to record tag number, date, breed, farm, comb, type of skin lesion (graze or cut). Lesions were classified as R (rayón = graze, superficial not penetrating the dermis) and T (tajo = cut, deep cut penetrating the dermis). A number was assigned to each lesion according to its dimensions (1: < 2cm; 2: de 2 a 5 cm y 3: > 5 cm). Nevertheless, due to the low frequency of some types of lesions, the different types of lesions were not considered in the analysis. The main effects analyzed were comb, shearer and session. Body condition score (BCS) was included in the model as a co-variable and ewes were grouped by BCS below 2.75 or equal or greater than 2.75. A binomial model was used to determine the probability of occurrence of lesions (present/not present) and a negative binomial model to determine the differences among mean values of lesions according to each factor. The effects of comb and shearer were significant; however, the effect of session was not on all occasions (and was not described in this study) and the effect of the covariable BCS was not significant. Few lesions occurred, independently from comb or shearer, and 54% of the ewes did not present any lesion, and the ewes that did present lesions the majority occurred on the dorsal side. The lesions were concentrated on the hindquarters and the axilla areas, while the udder and vulva areas were the least affected. The best results were obtained with the high shearing combs such as the R13 and the Chinese, which leave a more fleece and induce fewer lesions, in contrast with combs that leave less fleece such as the Standard and the Cover combs which induce more lesions. The differences in number of lesions among shearers suggest differences in skill and experience among them, leading to different performances.

Factores que afectan el score materno en ovejas Merino Australiano

Mariana Ferreira Álvarez — 2022-05-05

This study was carried out at the Experimental Station of the Faculty of Agronomy in Salto (EEFAS), with the data obtained from the lambing of the breeding Flock from 2015 to 2018. The objective was to evaluate the different factors that could be affecting the maternal score of the sheep. Data from 252 Australian Merino ewes were used, and 467 maternal score records were obtained; 67 records in 2015, 150 in 2016, 105 in 2017 and 145 in 2018. At the time of birth, information was recorded for both the lamb and the ewe, including the maternal score on a scale of 1 to 6. The factors analyzed were year of registration (1 to 4), age of the mother (2 to 10, years grouping the oldest ewes in ≥7 years), type of birth (single or twins), sex of the offspring (male, female or male/female, in the case of mixed-sex twins) and lambing group (group 1 = IATF lambing, group 2 = lambing from the first post-IATF estrus and group 3 = lambing from the second post-IATF estrus). The factors type of lambing, sex of the offspring and lambing group did not significantly affect the maternal score, so they were removed from the analysis. The factors that did affect the maternal score were year of registration (P=0.0087) and age of the mother (P=0.0616), increasing the probability of finding higher maternal scores as the age of the mother increased mother and with the increase in the years of registration. It can be affirmed that the experience of successive births by the ewe and the experience accumulated in management in general affect maternal behavior, and therefore the establishment of the maternal-filial bond. In the four years of registration, the maternal score improved, regardless of the number of sheep and the age structure of the flock in each year, which suggests that there was an improvement in management.

Evaluación del tipo de sorgo bajo pastoreo en la producción animal

Edgardo Bonjour Rodriguez — 2022-04-27

The purpose of this work was to address the stated objectives, evaluating the new alternatives of grazing forage sorghum and its response in animal production. The experiment took place at the Mario A. Cassinoni Experimental Station (EEMAC), of the Facultad de Agronomía, Universidad de la República, Paysandú, Uruguay. (32°22' 29.8" south latitude and 58°03' 43.4" west longitude), on Typical and Luvic Eutric Brunosols soils. The treatments under evaluation were 2, grazing of forage sorghum cv. Talismán (BMR) and grazing of forage sorghum cv. Green Supremo (FS). Animal productivity was evaluated, with the same grazing management between both treatments. The experiment had a design of plots divided into blocks with three replications. Two grazing cycles were carried out with 5 and 3 steers/plot for photosensitive materials and BMR successively. Holland breed animals were used, where the starting weight was adjusted between grazing cycles based on forage availability. The average weight was 530 kg in the first cycle, and 463 kg in the second. The different treatments did not present significant differences (p > 0.10) in terms of individual daily weight gain in the complete evaluation period (1.01 vs. 0.90 kg/an/day for FS and BMR successively). However, the treatments presented differences in the first grazing cycle (p < 0.10) in favor of the photosensitive material (1.29 vs 1.08 kg/an/day for FS and BMR successively). For the remaining parameters under evaluation, the lack of repetitions did not allow statistical analysis. The prevailing environmental conditions in the experimental period, characterized by low rainfall, were more decisive in the results obtained than the type of sorghum material used in grazing.

Estudio del fraccionamiento de la fertilización nitrogenada en maíz

Federico Daniel Canzani Valenzuela — 2022-04-22

This experiment seeks to generate information on fertilization strategies with nitrogen (N) in irrigated maize. The experiment was carried out in the experimental station “De. L. A. Cassinoni” in Paysandú, Uruguay, in the spring-summer 2019-2020. The effect of four levels of fractionation of the N dose was evaluated, under irrigation and rainfed conditions. This experiment consisted of six treatments: T1: 150 kg N ha^-1 fractionated 41 kg N ha^-1 in two leaves (V2) and 109 kg N ha^-1 in six leaves (V6) under irrigation, T2: 150 kg N ha^-1 fractionated 21 kg N ha^-1 in V2 and four applications of 33 kg N ha^-1 between V6 and tasseling (VT) under irrigation, T3: 150 kg N ha^-1 divided into 21 kg N ha^-1 in V2 and seven applications of 19 kg N ha-1 between V6 and tasseling (VT) under irrigation, T4: 150 kg N ha^-1 fractionated 41 kg N ha^-1 in two leaves (V2) and 109 kg N ha^-1 in six leaves (V6) under rainfed conditions, T5: 150 kg N ha^-1 fractionated 21 kg N ha^-1 in V2 and four applications 33 kg N ha^-1 between V6 and tasseling (VT) under rainfed conditions, T6: 150 kg N ha^-1divided into 21 kg N ha^-1 in V2 and seven applications 19 kg N ha^-1 between V6 and tasseling (VT) under rainfed conditions. The factorial arrangement used was divided plots, with three blocks where the largest plot was the water availability and the least was the fractionation of N. When performing the statistical analysis, an interaction was found between the fractionation of the N dose and the water availability for the yield. Where under irrigation conditions significant differences in yield were found for the different levels of fractionation, having obtained a higher yield where T4 was applied. Fractionation had an effect on PG, which explains the differences in performance in favor of the T4. Regarding the NG, no significant differences were detected between the different levels of fractionation. The PG by surface was the component that had more correlation with the yield (R²: 0,83), the effect of NG being the least important (R²: 0,56). The results indicate that under irrigation conditions or abundant PP, the fractionation of the N dose allows satisfying the needs of N during grain filling, which allows an increase in the PG, which means an increase in grain yield.

Caracterización y evaluación de rizobios como promotores del crecimiento en arroz

Andrea Amarillo — 2022-04-19

One of the interactions between plants and microorganisms of greatest biological and agronomic interest is the symbiosis between the Legume family and bacteria called rhizobia. These bacteria can also establish an interaction as endophytes with other families such as grasses and to enhance production in species such as rice (Oryza sativa). This crop is of particular importance in our country for its contribution to the national economy as well as for being a sector with international recognition in some aspects such as the quality of the exported product, the integration in the stages of the productive chain and the lines of research developed.

In this work, 14 rhizobial strains nodulating white clover (Trifolium repens) and 16 nodulating bird´s-foot trefoil (Lotus corniculatus), previously isolated from disinfected roots of rice plants from the long-term experiment of Paso de la Laguna, INIA, Treinta y Tres were characterized. The strains used in commercial inoculants U531 Mesorhizobium loti, U510 Mesorhizobium huakuii and U204 Rhizobium leguminosarum bv. trifolii were also included. The strains were screened for their colonization capacity and plant growth promoting traits, such as: symbiotic efficiency, pectin degradation, mobility, biofilm production, phosphate solubilization, indole acetic acid synthesis and ability to promote seed germination of Oryza sativa. The results showed variability among the strains, some strains stood out showing to be candidates to continue evaluating in inoculation tests.

Three of the strains nodulating Lotus corniculatus, 3 nodulating Trifolium repens and the strains of the commercial inoculants U510, U531 and U204 confirmed their interaction with rice plants cultivar INIA Olimar being able to colonize and persist in the roots up to 30 days post inoculation in greenhouse. Among the 9 tested strains, strain U204 Rhizobium leguminosarum bv. trifolii, showed the ability to promote growth of rice plants grown in sand: vermiculite showing a significant increase in shoot and root dry matter. It is necessary to check these results in future inoculation trials using soil as substrate and under field conditions.

Gestión colectiva de tierras del Instituto Nacional de Colonización

Gian Franco Rodríguez Riva — 2022-03-22

This thesis is focused on the study of two settler groups, belonging to the INC, whose main activity is family farming. The Arerunguá group is located in the department of Salto, while Paso de los Carros is in Paysandú. By surveying the trajectory of the groups and their members, we sought to understand the internal processes of the INC's collective self-management of lands; particularly, in aspects related to the management of the natural field as a resource of common use. The work methodology was based on conducting semi-structured interviews with qualified informants and the producers who are members of the groups analyzed, trying to cover differentiated profiles in the latter. After processing the information, the analysis shows that, in this type of enterprise, trust among the members is a fundamental factor to achieve the objectives set by the group. In the delegation of roles, the most prominent in relation to the management of the common use asset is the field manager or foreman, who has the daily responsibility of managing the resource and informing his peers about what has happened, trying to achieve proper management sustainable of it. In learning, the incorporation of knowledge through interaction with technicians and training activities, linked to productive and social aspects, which over time are capitalized in the internal organization of the group, stands out. In operation, the operative and collective rules are the ones with the greatest incidence, those that have evolved over the years based on learning and the opportunities to incorporate technologies that benefit the management of the common benefits. The social interaction and the involvement of the members in the actions of the collective is what sustains the continuity of the joint venture.

Caracterización de la comunidad de enterococcus presente en queso colonia con énfasis en la distribución de resistencia a antibióticos

Estefania Amaro Aguirre — 2022-03-18

The cheese industry in Uruguay produces about 5.3% of the total milk production and represents 26% of the country's dairy farms, which produce 50% of the total cheese consumed in Uruguay. Colonia cheese is a typical Uruguayan cheese, produced according to the quality criteria and tradition of Swiss immigrants who settled in the Colonia dairy basin. It is a cheese of medium humidity and its main characteristic is the presence of irregular-sized eyes. In this work, Colonia cheeses from neighborhood fairs and supermarkets in Montevideo were analyzed. The microflora of these cheeses was quantified, with emphasis on the population of Enterococcus spp. The presence of enterococci in cheeses can have contradictory effects, either as a risk due to their pathogenic potential, or as a benefit to produce unique traditional products. Enterococci counts were observed in 24 of the 36 samples analyzed, with a maximum count of 1.25E+05 and an average of 1.43E+04. Resistance to different antimicrobials was also evaluated in 84 enterococci isolates. All isolates showed resistance to at least one antimicrobial. The risk of contamination of the samples with multidrug-resistant enterococci was evaluated using the MAR-Index, for which it is established that a value greater than or equal to 0.2 considers the microbial population to be at risk given the high level of observed resistance. In this study, the average MAR-Index was 0.33, so the population of Enterococcus spp. isolated from Colonia cheese represents a potential risk to human health that should be monitored.

Possible technological applications of the isolates obtained were also evaluated. Lipolytic and proteolytic activity and the production of metabolites such as diacetyl by the decomposition of citrate, all biotechnological characteristics of interest to the cheese industry, were evaluated. Of the 16 isolates selected for their low pathogenic potential, only one showed proteolytic activity and none showed lipolytic activity or utilization of citrate as the sole carbon source.

Revisión taxonómica de Piptochaetium J. Presl (Gramineae: Stipeae) en Uruguay

Carla Ricca — 2022-02-14

This article introduces a taxonomic revision of Piptochaetium J. Presl. (GRAMINEAE: Stipeae) for Uruguay. The genus in Uruguay is composed by twelve species and two varieties. Herbarium material was analyzed from the Faculty of Agronomy of Montevideo, Bernardo Rosengurtt, together with field observations. The original descriptions were examined material.

This work includes dichotomous keys to species, detailed descriptions, synonymies, illustrations, photographs and distribution maps.