Carbon and nitrogen mineralization kinetics in soil of rice–rice system under long term application of chemical fertilizers and farmyard manure

• DOI: 10.1016/j.ejsobi.2013.07.004
• Publication Date: 2013-08-02T14:00:35Z
• Authors: Sangita Mohanty; A.K. Nayak; Anjani Kumar; Rahul Tripathi; Mohammad Shahid; P. Bhattacharyya; R. Raja; B.B. Panda
• Keywords: Nitrogen Cycle; Soil carbon; Long-term experiment

Abstract Quantitative information on carbon (C) and nitrogen (N) mineralization of soil under different long term nutrient management strategies is essential for better assessment of N availability and loss of C and N from soil. A laboratory incubation study was conducted with soils (0–15 cm and 15–30 cm depth), collected from 41 years of rice–rice system to evaluate the differences in C and N mineralization kinetics due to long term fertilization treatments-control (Non fertilized), N, NPK, FYM (Farmyard manure), N + FYM and NPK + FYM, and to assess the C and N mineralization rates in soil under different moisture regimes, i.e. aerobic and submergence. Both long term fertilization and moisture regime significantly affected C and N mineralization in soil. Long term integrated application of chemical fertilizer and organic manure (NPK + FYM, N + FYM) in soil resulted in higher potentially mineralizable C (C 0 ), potentially mineralizable N (N 0 ), rates of mineralization ( d C min / dt and d N min / dt ), microbial and mineralization quotients as compared to either of them applied alone (N, NPK, and FYM). Higher values of C 0 , N 0 , and rates of mineralization were recorded under aerobic condition than that under submergence. The amount of N released per unit C mineralization was higher in aerobic system that may result in greater loss of N from the system. A judicious N application strategy through integration of both organic and inorganic sources is essential for improving current N supplying capacity of soil and maintaining soil organic C pool in aerobic system.