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

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.