Study on CH4 and N2O emissions from water-saving irrigation in Phaeozem paddy fields in cold areas

摘要

Increasing greenhouse gas emissions and water shortage are two main problems associated with cultivation of rice. Soil moisture control is not only a core technology in water-saving irrigation, but also a decisive factor of greenhouse gas emissions. The CH4 and N2O emission fluxes from intermittent irrigation and flooding irrigation in Phaeozem paddy fields in cold area were measured in-situ to provide a theoretical basis for studying the regulation of CH4 and N2O emissions and comprehensive assessing the effect of intermittent irrigation on the environment and control of greenhouse gas emissions. During the rice growing period, CH4 emissions peaked at the tillering stage, whilst N2O emissions peaked twice at the tillering and milky ripening stages. The accumulated emission of CH, from the implementation of flooding irrigation in paddy fields was 6.46 gm(-2), whilst that from intermittent irrigation was 5.47 gm(-2). The accumulated emission of N2O from the implementation of flooding irrigation in paddy fields was 36.88 mgm(-2), whilst that from intermittent irrigation was 68.47 mgm(-2). The global warming potential of CH4 and N2O was 1362.7 1kgCO(2)ha(-1) from intermittent irrigation in paddy fields, a value 108.12 kgCO(2)ha(-1) lower than that from flooding irrigation. Intermittent irrigation can thus be used to effectively decrease and control the combined greenhouse effect of CH, and N2O emissions from rice paddy fields.