稻田CH4和N2O排放消长关系及其减排措施

Trade-off Relationship and Mitigation Options of Methane and Nitrous Oxide Emissions from Rice Paddy Field

稻田CH4和N2O排放存在互为消长的关系,此种关系不受时间、空间及有无水稻植株的影响,考虑稻田CH4减排措施的同时必须兼顾该措施对N2O排放的促进作用。本文从水分管理、施肥管理、水稻品种、甲烷抑制剂及脲酶/硝化抑制剂、耕种方式及耕作制度等方面综述了近年来关于稻田CH4和N2O减排措施的研究,以期从农业实践中总结缓解稻田CH4和N2O排放引起的综合温室效应的生产措施。分析表明,稻田低施氮水平条件下进行中期烤田是减少CH4和N2O排放的有效措施,有机秸秆进行堆腐好氧分解后施入或在休闲期(如秋季或冬季)施入稻田表现出较好的应用前景,施用甲烷抑制剂、脲酶抑制剂及硝化抑制剂和缓释/控释肥料对降低稻田温室气体排放及提高作物产量意义重大。

A trade-off relationship was found existing between methane （CH4）and nitrous oxide （N20）emissions from rice paddy field and was not affected by seasonal variation, spatial changes and whether the crop was planted or not. Mitigation of CH4 emission would bring about more N2O emission. Effects of both CH4 and N2O emissions from rice paddy field on global warming potential（GWP）should be taken into consideration when any mitigation options are to be established. In this paper, studies focused on mitigating CH4 and N2O emissions from rice paddy fields were summarized and the rice cultivation methods which could decrease the global warming potential were proposed. Those mitigation options commonly studied and used including water regime management, fertilization, selection of rice cultivar varieties, application of inhibitors （methane inhibitor, urease inhibitor and nitrification inhibitor, etc）, tillage, rice-wheat rotation and so on. In general, midseason aeration of paddy fields with low dosage of nitrogen fertilizer after short-term drainage was one of the most promising strategies for reducing CH4 and N2O emissions. Improving organic matter management by promoting aerobic degradation through composting or incorporating crop straws into soil in autumn or winter was another one. It was also useful to apply methane inhibitor, urease inhibitor, nitrification inhibitor and slow/control-released fertilizer to increase rice yield and decreased greenhouse gases emissions from rice paddy field.