Efecto de diferentes cultivos de servicio invernales sobre la condición nitrogenada y el rendimiento del cultivo de trigo sucesor

This study aimed to evaluate the effect of different winter cover crops on the nitrogen status and grain yield of a subsequent wheat crop following maize. In the current context of low crop diversification, declining productive capacity and system sustainability, and a high dependence on external inputs, particularly nitrogen fertilizers, the inclusion of cover crops was assessed as an alternative management strategy. Oat (Avena byzantina), hairy vetch (Vicia villosa), and their mixture were evaluated for their potential to provide complementary ecosystem services and improve the performance of the subsequent wheat crop.

The experiment was conducted at the Mario A. Cassinoni Experimental Station, located in Paysandú, Uruguay. A randomized complete block design with four treatments and three replications was established, including a split-plot arrangement to evaluate the interaction between cover crop effects and different nitrogen fertilization strategies (no N, adjusted N, and non-limiting N). Soil nitrate concentration, cover crop biomass production, nitrogen uptake, wheat grain yield, and other agronomic variables were measured.

Results showed that the residual effect of legume cover crops on nitrogen dynamics persisted until the second crop in the sequence. Hairy vetch as a preceding cover crop increased nitrogen availability for wheat, allowing a reduction in the total amount of fertilizer N applied without affecting grain yield. Under nitrogen-limiting conditions, hairy vetch increased wheat yield compared with the other cover crop treatments. In contrast, under non-limiting nitrogen conditions, the benefits associated with legume cover crops disappeared, as fertilizer N replaced the nitrogen contribution provided by the cover crop. Under these conditions, wheat performed better following grass cover crops, suggesting that once nitrogen limitations are removed, other benefits associated with grasses, such as increased organic matter inputs, greater soil cover, and improved soil physicochemical properties, may become more relevant. These effects warrant further evaluation in the medium and long term.