间歇灌溉模式下稻田CH_4和N_2O排放及温室效应评估

CH_4 and N_2O Emissions and Their GWPs Assessment in Intermittent Irrigation Rice Paddy Field

【目的】研究间歇灌溉和长期淹灌模式下稻田CH4和N2O排放规律及其温室效应,为全面评价不同水分管理对稻田生态环境带来的影响及有效控制稻田温室效应提供理论依据。【方法】采用静态箱技术对稻田CH4和N2O排放通量进行监测,并运用增温潜势对稻田生态系统CH4和N2O排放的温室效应进行了估算。【结果】间歇灌溉稻田CH4排放峰值主要集中在水稻分蘖前期和中期,N2O排放峰值出现在水稻分蘖前期和成熟期。与长期淹灌相比,间歇灌溉稻田CH4排放通量明显降低,其累积排放量为20.04 g.m-2,比长期淹灌处理37.27 g.m-2减少了46.23%;而N2O累积排放量显著高于长期淹灌稻田,其排放量为127.42 mg.m-2,比长期淹灌处理增加51.36 mg.m-2。间歇灌溉稻田CH4和N2O温室效应总和为4651.70 kgCO2.ha-1,比长期淹灌处理减少3418.35 kgCO2.ha-1。【结论】间歇灌溉能有效地抑制温室气体排放并显著降低CH4和N2O的温室效应。因此,间歇灌溉是减少温室气体排放和减轻全球变暖的有效措施之一。

[Objective] CH4 and N2O emissions from intermittent and flooding irrigation rice paddy fields and their GWPs were studied to provide a theoretical basis for comprehensively assessing the effect of water management on the environment and controlling greenhouse effect. [Method] CH4 and N2O emissions from rice paddy fields were measured in situ by using static chambers technique, and the greenhouse effect of CH4 and N2O were assessed using global warming potentials （GWPs）. [Result] The peak of CH4 emission appeared at initial and middle tillering stages, and the peak of N2O emission was observed at initial tillering and ripening stages. Compared with flooding irrigation, intermittent irrigation model significantly decreased CH4 emission, the accumulated emission was 20.04 g·m^-2, which was about 46.23% lower than that of 37.27 g·m^-2; but the N2O accumulated emission was 127.42 mg·m^-2, which was about 51.36 mg·m^-2 higher than that of flooding irrigation. The GWPs of CH4 and N2O was 4651.7 kgCO2.ha^-1, which was about 3418.35 kgCO2.ha^-1 lower than that in intermittent irrigation rice field. [Conclusion] Intermittent irrigation model can effectively decrease and control CH4 and N2O emissions, and it is one of the effective strategies to reduce greenhouse effect from rice paddies field and will contribute to alleviating global warming.