Simulation of Soil Organic Carbon Dynamics in Oasis Farmland in Xinjiang Based on DNDC Model

This paper reports a study of long-term fertilization impacts on soil organic carbon (SOC) dynamic using DNDC (denitrification-decomposition) model to simulate the related experimental parameters in Manas Country, Xinjiang province. RMSE, M, R² and r values were used verification the DNDC model. Meanwhile, the simulation predicted that fertilizer (N+P+K) +S(S, plant residue returned) treatment change trend of SOC in the different soil types, and analysis of corresponding of ΔSOC and the initial value in soil chemical and physical properties. In addition, based on GIS the spatial distribution was calculate by SOC content, bulk density, depth, density of soil carbon conversion (SOCD). Results showed that through DNDC model simulation SOC increased 1.9g kg^-1 from 2011 to 2041 year; soil carbon density ranges from 0.012kg C m^-2 yr^-1 to 0.021 kg C m^-2 yr^-1. Soil carbon sequestration rate ranges from 207kg C ha^-1 yr^-1 to 121kg C ha^-1 yr^-1. Carbon density of the Manas country farmland was increasing. Moreover, high SOC content has higher sequestration rate than low SOC content.