Nitrous oxide emission from paddy fields in China

The main research results of nitrous oxide (N2O) emission from paddy fields in China were summarized. Paddy fields are an important source of N2O emission. Denitrification process exists not only in the upper flooded cultivated layer in paddy fields but also in the underground saturated soil layer. The cropping system with rice–wheat rotation and the water regime with mid-season aeration (MSA) in paddy fields of China are not only the controlling factors of N2O emission but also the main factors influencing methane (CH4) emission. There is a trade-off relationship between N2O and CH4 emissions from paddy fields. Straw amendment reduced N2O emission but promoted CH4 emission. Therefore, effects of both CH4 and N2O emissions from rice fields on the global warming potential (GWP) should be taken into consideration when any mitigation options are to be established.