Modelling the Spatial Variation of Methane and Nitrous Oxide Emission from Rice Fields Using DNDC Model

Methane (CH4) and nitrous oxide (N2O) emissions coupled with climate change are issues which are of great concern for modern rice cultivation. It is very difficult and costly affair to quantify the CH4 and N2O emissions at regional and national scales due to large scale spatial and temporal variability in soil and crop management practices. In this study, the denitrification and decomposition (DNDC) model was used for simulating the CH4 and N2O gas emissions from rice fields in Eastern India. For simulating the gaseous emission, the maps of pH, bulk density, soil organic carbon and clay content were prepared using geostatistics and ordinary kriging with study area divided into 1178 grids with an area of 32 ha for each grid. The maps along with other datasets used for running the DNDC model were compiled as model input parameter. The model was then applied for simulation of methane and nitrous oxide emissions from rice fields with various management practices. Simulated CH4 emission in the study area ranged from 9.38 to 110.63 kg C ha(-1) and N2O emissions ranged from 0.01 to 1.82 kg N ha(-1) as simulated by the DNDC for the crop growing season. Simulated CH4 emission ranged from 0.07 to 1.15 kgC/ha/day, whereas N2O reached upto 8.96 g N ha(-1) day(-1). The study suggested that the DNDC model can be used for estimating the CH4 and N2O emissions by capturing the information about the different crop management practices from rice fields.