Effects of tillage practices on soil carbon storage and greenhouse gas emission of farmland in North China

Distribution of soil organic carbon in different soil layer can be transformed by tillage practices, and then soil carbon storage was changed. The four indices of soil organic carbon (SOC), soil carbon density (SCD), soil respiration (SR) and biomass carbon (BC) were selected to verify the adaptability of DNDC model in North China based on model adaptation and then the model was used to simulate local dynamic change of soil carbon storage (SCS) and characteristics of greenhouse gas emission. The result showed that there was a high similarity between simulated values and observed values and the model proposed was suitable to apply to the simulation research of soil organic carbon for winter wheat-summer corn in North China. SOC and SCS simulated by the model increased from 2001-2010, and simulated data in the next 100 years showed that SOC with rotary tillage (RT), conventional tillage (CT) and no-tillage (NT) showed a severe rising tendency in the first 15 years, and rising tendency of NT could sustain for 40 years. By comparing changes of soil carbon storage for 100 years between each treatment, it was found that SCS values with CT were the highest in the first 20 years and SCS values with NT was the highest after first 20 years. The sequence of global warming potential (GWP) for each treatment was CT＞RT＞NT. The results showed that DNDC model could work well for winter wheat-summer corn in North China, and NT was beneficial to increase SCS and decrease GWP of farmland in the long run. It provides a reference for fixing carbon and reducing discharge of winter wheat-summer corn in North China.