Carbon dynamics under long term integrated nutrient management

Abstract

The effect of integrated nutrient management (INM) on carbon pools of soil organic carbon (SOC) under Rice-wheat cropping sequence of a calcareous soil was studied in a long-term field experiment initiated during Rabi 1988 at Pusa, Bihar. Effect of varying doses of NPK with compost, crop residue, compost+ crop residue after 28th year of Rice-wheat crop sequence was studied. All the levels of fertilizers significantly affected the KMnO4-C content of soil. The maximum KMnO4-C (0.86 g kg-1) was found to be in the treatment receiving both compost and crop residue which was 45.76% higher than that no manure application The maximum carbon management index (155.68%), obtained in the treatment receiving 150% NPK, was 4.71, 15.10 and 26.09% higher than the treatments receiving 100%, 50% and No NPK, respectively. Addition of manure increased the both labile and non- labile pools of carbon but, increment is higher in non-labile pool than labile pool. Integrated nutrient management resulting in enhanced carbon management index indicated favorable impact of integrated nutrient management on carbon stabilization in soil.