Effect of Nutrient Management on Soil Carbon Quantities, Qualities, and Stock under Rice-Wheat Production System

The nutrient management options have been contemplated to be sustainable strategies to sustain rice-wheat production systems and a conceivable option to maintain soil organic carbon (SOC) in soil systems. We hypothesized that carbon fraction could be a critical factor in improving carbon storage in cereal-based production systems. The results suggested that the adoption of IPNS legumes (berseem and cowpea), STCR, and OF improved SOC concentrations. It was observed that significantly higher (57%) contribution in carbon concentration very labile carbon (VLC) was trailed by the non-labile carbon (NLC, 23%), labile carbon (LC, 12%), and less labile carbon (LLC 8%) in the surface soil layer. Results showed that carbon stock varied from 11.73 to 18.39 and 9.95 to 11.75 t ha−1 in the surface and subsurface soil depths, respectively, and significantly higher carbon stock was maintained in OF in both soil depths over the other nutrient management practices. Results showed that for the surface layer C-stocks registered in the following order (0–15 cm soil depth) OF (18.39 t ha−1) > IPNS + C (17.54 t ha−1) > IPNS + B (17.26 t ha−1) > IPNS (16.86 t ha−1) > STCR (15.54 t ha−1) > NPK (15.32 t ha−1) and unfertilized control (11.73 t ha−1). Overall, results suggested that the adoption of IPNS options addition of legumes significantly enhanced all carbon pools.