INTEGRATED CROP-LIVESTOCK SYSTEMS IN LOWLANDS OF SOUTHERN BRAZIL: IMPLICATIONS FOR SOIL PHYSICAL ATTRIBUTES AND ORGANIC CARBON STOCKS

Abstract

Lowland soils exhibit conditions of high hydromorphism, which poses a challenge for the introduction of upland species and the adoption of conservation agriculture principles. Crop rotation with economically valuable species has been tested as a strategy to promote the sustainability of production systems and improve the physical quality of lowland soils. This study aimed to evaluate the influence of integrated annual grain cropping and livestock systems on the physical and chemical quality of a Planosol. Four agricultural areas located in the municipalities of Capão do Leão and Arroio Grande, in the state of Rio Grande do Sul (RS), were assessed. Undisturbed soil samples were collected at depths of 0.00–0.05 m, 0.05–0.10 m, and 0.10–0.20 m. Physical attributes (density, porosity, water-stable aggregates, and soil-water retention curve) and chemical attributes (soil organic carbon stocks) were analyzed. The results showed that the integrated crop-livestock system conducted on broad-base ridges presented limitations in soil physical quality, with lower mean values of total porosity and carbon stocks, likely due to a high livestock load pressure. This study concluded that the quality of lowland soils could be improved through the adoption of annual crop rotations  and increased annual inputs of organic residues in integrated cultivation systems.