Long-term impact of reduced tillage and residue management on soil carbon stabilization: Implications for conservation agriculture on contrasting soils

The long-term effects of tillage system and residue management on soil organic carbon stabilization are studied in two tropical soils in Zimbabwe, a red clay and a sandy soil. The four tillage systems evaluated were conventional tillage (CT), mulch ripping (MR), clean ripping (CR) and tied ridging (TR). Soil organic carbon (SOC) content was measured for each size fraction as well as total SOC. Based on the findings, the authors conclude that residue management - maintaining carbon inputs - is most important for SOC stabilization in coarse-textured soils, whereas reducing tillage is the management priority for fine-textured soils.