Abstract—S ince the early 1980s water management strategies in rice paddies in China has changed substantially, with midseason drainage gradually replacing continuous flooding. Using the process-based DNDC model and county-level database, we simulated CH4, N2O emission and yields from paddy fields under this change. Results indicated this change had reduced CH4 emission by approximately 41% from 2006 to 2010 and the mitigating effect was highly uneven across the country. The highest flux reduction (>1000 kg CH4-C ha-1 yr-1) were Hainan, Hubei, Guangxi provinces with warm weather and multiple-cropping rice systems and the lowest flux reduction (<300 kg CH4-C ha-1 yr-1) appeared in Tianjin, Heilongjiang, Liaoning provinces, with cold weather and single cropping systems. Meanwhile N2O emission was stimulated by 106% on average during this period, which offseted a large amount of the GHG radiative forcing benefit gained by CH4 decreases. Rice yields were closely related with the intensity and the interval of drainage. This study concluded DNDC model would play an essential role to optimize county-level water management schemes across China. 
 

Index Terms—mid-season drainage, continuous flooding, rice yield, greenhouse gas emission

Cite: Han Chen, Chaoqing Yu, Changsheng Li, Xuecao Li, Jie Zhang, and Wei Wang, "Modeling the Impacts of Water Management Change on Greenhouse Gas Emission and Yields from Paddy Fields in China During 2006-2010," Journal of Advanced Agricultural Technologies, Vol. 3, No. 1, pp. 42-48, March 2016. Doi: 10.18178/joaat.3.1.42-48