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

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.