Soil Carbon Sequestration Through Conservation Tillage and Residue Management

To mitigate the changing climate due to the increase concentration of greenhouse gases (GHG) in the atmosphere, studies on carbon (C) sequestration potential of different agricultural management practices are receiving worldwide attention. Conservation agriculture (CA) is highly recommended for its high C sequestration capacity and the productive use of crop residues that are otherwise burnt and pollute the environment. The adoption of CA offers preservation of soil moisture by leaving at least 30% of the soil surface covered with crop stubble/leaf litters, thereby decreasing wind and water erosion. The amount of residue cover left on the field depends on the type of operation, availability of implements and the fragility of the residue. Under CA, if 1 ft of residue is left on the field, an additional amount of 1.6–2.0 t/ha of crop residue is being added in to the field compared to farmers’ practice that improves soil aggregation, infiltration, organic C status and enhanced biological properties. The C sequestration in CA is accomplished through the addition of carbon through residues, protection of soil organic carbon in soil aggregates under minimum soil disturbance and addition of soil organic carbon (SOC) to deeper soil layer due to the inclusion of legumes in the cropping system. In fact, practising CA can potentially sequester C at rates of 300–600 kg C/ha/year depending on the type of soil and climatic conditions. In addition, CA practices are widely adopted to increase soil productivity, revert soil degradation, improve C sequestration and also increase input use efficiency and crop yields. Therefore, location-specific CA must be developed and advocated. The challenges and bottlenecks in disseminating CA in a large scale must be addressed and overcome by further studies with policy initiatives and interventions.