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

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.