[目的]探讨耕作方式和施氮肥对稻田CH4排放的影响.[方法]设常耕、免耕两种耕作方式和施氮、不施氮两种施氮模式共4个处理,研究其CH4排放随水稻生长的动态变化和日变化的规律.[结果]各处理稻田CH4排放表现为双峰型模式,峰期分别出现在分蘖期和抽穗期.水稻拔节前,免耕明显降低稻田CH4的排放通量.水稻拔节后,免耕稻田CH4排放通量高于常耕稻田.免耕水稻全生育期稻田CH4排放量比常耕减少32.35％.两种耕作方式下,与不施氮处理相比,施用氮肥提高稻田CH4排放通量2.73～3.26倍.常耕、免耕稻田CH4排放的日变化存在差异.免耕稻田CH4排放通量峰值出现较晚,低谷期出现较早,日变化幅度较小.[结论]免耕水稻全生育期稻田CH4排放通量比常耕低,施用氮肥显著提高稻田CH4的排放.%This research aimed to explore the effects of tillage pattern and nitrogen fertilizer on CH4 emission from rice field. [ Method]The changes in rice growth daily variations of CH4 emission under two kinds of farming methods (conventional tillage and no-tillage), and two kinds of N levels(N and no-N)in fields were explored and analyzed. [Result]The CH4 emission of each treatment generally displayed a bimodal peak pattern, which was at the tillering stage and heading stage, respectively. Before rice elongation, the no-tillage treatment clearly reduced the CH4 emissions flux from rice fields. After rice elongation, the.. CH4 emission flux from no-tillage rice fields was slightly higher than that of the conventional tillage rice fields. The no-tillage treatment reduced the CH4 emissions flux by 32.35% in total compared to that from the conventional tillage treatment during rice growing period. In both farm lands, the nitrogen fertilizer dramatically increased the CH4 emissions by 2.73-3.26 times compared to no-nitrogen fertilizer treatment. The diurnal variation of CH4 emissions from the rice fields significantly differed from eachother under different tillage patterns. The peak of CR, emissions flux from the no-tillage rice fields appeared later, while the dip occurred earlier; its diurnal variation also changed slightly. [ Conclusion ]The CH4 emission flux from no-tillage rice fields was lower than that from the conventional tillage rice fields throughout the rice growing period. Nitrogen fertilization significantly improved the paddy CH4 emissions.
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