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

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.