关键词: 免耕, 晚稻, 稻－鸭种养, CH4排放, 减排措施, 经济评价

Abstract: 【Objective】The rice-duck ecological system is one of the cream practices from the traditional Chinese agriculture. Study on the effect of reducing methane-emission of this practice could provide theoretical and practical basis for further development and utilization of this classical agricultural technique.【Method】The effect of reducing methane-emission and the economic benefits of rice-duck ecological system were studied by adopting a field experiment and economic methodology. 【Result】The daily variation of CH4 emission in late rice paddy field was basically consistent with the daily variation of air temperature. The highest emission occurred at the full tillering stage of late rice with a rate of 24.1 or 32.2 or 40.5 mg·m-2·h-1 in no-tillage area with duck and no-tillage area without duck and conventional-tillage area without duck, respectively. The inhibition of methane-emission was apparently effective in the rice-duck ecological system during the initial tillering stage and the full tillering stage. Compared to the no-tillage area without duck, methane-emission decreased by 2.333 g·m-2. While compared to the conventional-tillage area without duck, methane-emission decreased by 4.723 g·m-2 growth. During the production period of late rice, the amount of methane-emission in no-tillage area with duck was 3.373 g·m-2 less than that of no-tillage area without duck, and 5.59 g·m-2 less than that of conventional-tillage without duck area. The economic significance was analysed. Farmers adopting the rice-duck ecological system obtained 2 166 and 4 207 yuan/ha more income than those who adopted a no-tillage without duck technique or conventional-tillage without duck technique, respectively. In addition to the reduction of the environmental pollution by methane emission, the farmers who adopted the rice-duck ecological system achieved economic benefits of 5 000 yuan/ha, which is 2 206 and 4 274 yuan/ha more than those who adopted a no-tillage without duck technique and a conventional-tillage without duck technique, respectively. 【Conclusion】The rice-duck ecological system not only increased the economic benefits of farmers, but also reduced methane emission in rice paddy field A sustainable agricultural production mode is formed.

Key words: No-tillage, Late rice, Rice-duck system, Methane emission, Mitigation options, Economic evaluation