Effects of soil tillage practices on soil conservation in pasture-based integrated management systems: a case study on steep slopes in southeastern Brazil

Conservation tillage practices within integrated systems offer a viable strategy for restoring degraded pastures on slopes. This study evaluated the short-term (2 years) impacts of soil tillage types and young silvopastoral systems on soil hydrophysical properties, CO2 emissions and erosion processes in a 38% sloping area following pasture renovation. Three management systems (full-sun pasture; and silvopastoral system with eucalyptus or with gliricidia) were evaluated alongside three soil tillage types (downhill ploughing with a disc plough; contour ploughing with a mouldboard plough; and no-tillage). The results revealed that soil tillage led to bulk density and penetration resistance reductions of up to 85% compared to no-tillage. The decrease in bulk density was associated with increased total porosity (particularly macroporosity), resulting in enhanced soil water infiltration rates (up to > 76.5%). However, disturbance induced significant environmental disadvantages, including nearly twofold increases in soil losses, water losses and increased CO2 emissions (> 43%). Young silvopastoral systems demonstrated a soil hydrophysical quality comparable to full-sun pasture and did not significantly affect CO2 emissions, soil water content or temperature. Notably, no-tillage resulted in lower CO2 emissions and soil temperatures but higher soil water content, particularly when integrated with tree species, effectively minimizing soil and water losses. These findings underscore the critical role of no-tillage practices within silvopastoral systems in enhancing soil conservation, especially on erosion-prone sloping lands.