Soil carbon dynamics in response to compost and poultry manure under rice (Oryza sativa)–wheat (Triticum aestivum) crop rotation

An experiment was conducted during 2007–09 at New Delhi, to study effect of composted cereal wastes, poultry manure and chemical fertilizers on soil carbon pools under rice (Oryza sativa L.)–wheat (Triticum aestivum) crop rotation. Analysis was carried out for organic carbon, oxidizable carbon and its four fractions, microbial biomass carbon and dehydrogenase activity at harvest stage. Soil fertilization with half the recommended dose of NPK+ compost @ 3 Mg/ha or poultry manure @ 3 Mg/ha added separately, increased the soil organic carbon content significantly as compared to chemical fertilization after two cycles of rice–wheat cropping system. Compost + NPK amended soil not only resulted in improved harvest index (0.470) but also showed highest content of non-labile pool of carbon fractions (11.80 mg/g) and improved the grain yield by 33.24%. Therefore, integrated use of chemical fertilizer and compost at 3 Mg/ha to be a feasible option for storing and sequestering soil carbon at half of its recommended dose with improving crop productivity in rice–wheat crop rotation.