节水灌溉模式对稻田CH4排放规律的影响

基于水稻节水灌溉技术和密闭静态箱技术田间原位采集甲烷气样，试验研究了水稻节水控制灌溉模式对稻田CH₄排放规律的影响.结果表明，控制灌溉稻田CH₄排放呈现明显的下午极大值型日变化，CH₄排放高峰主要出现在下午13:00，淹水处理CH₄排放峰值在1 d中各个时刻的出现具有一定的随机性.控制灌溉稻田CH₄排放呈现明显的单峰型季节排放规律，排放高峰发生在分蘖前期，比淹水处理提前了10 d.所以，控制灌溉模式在水稻返青期后的水分调控及生产性用水等水管理措施对稻田CH₄排放的影响至关重要.控制灌溉水稻全生育期的稻田CH₄排放总量为24.46 g·m^-2，比淹水稻田减少了39%，平均排放率为7.96 mg·(m²·h)^-1，但返青期和分蘖前期的CH₄平均排放率比淹水稻田高，在以后的各个生育阶段均低于淹水稻田.

Effect of Water-Saving Irrigation on the Law of CH4 Emission from Paddy Field

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.