Effect of Water-Saving Irrigation on the Law of CH4 Emission from Paddy Field
节水灌溉模式对稻田CH4排放规律的影响

Based on rice water-saving irrigation technique and observation in situ with closed static chamber technique, field experiment was carried out to investigate the effect of rice water-saving controlled irrigation on the law of CH4 emission from paddy field. The results show that the diurnal variation of CH4 emission from paddy field under controlled irrigation (PFCI) appears regular afternoon-maximum model, mainly at 13:00, but that from paddy field under flooding irrigation (PFFI) appears random model. The seasonal variation of CH4 emission from PFCI takes on distinct one-peak pattern, occurring at the initial tillering stage of rice, more than 10 days earlier than that from PFFI. So, water regulation and practical irrigation of control irrigation model, especially after rice turning-green stage, is quite important to affect CH4 release from paddy field. The total CH4 emission from PFCI is 24.46g·m-2, the seasonal average of CH4 emission rate is 7.96 mg·(m2·h)-1, reduced by 39% compared with that from PFFI. But the mean emission rate of CH4 from PFCI is higher during rice turning-green and initial tillering stage, and lower than that from PFFI.