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.