[Effect of Dicyandiamide on N₂O Emission in Fallow Paddy Field and Rape Cropping]

The emissions of greenhouse gas in winter are often neglected, and the latest research results showed that N₂O emissions in fallow paddy field and winter oilseed rape are still large, research on mitigating the N₂O flux and the mechanism behind them is of significance for mitigating N₂O emissions from agricultural soil. By using static chamber techniques and molecular biology techniques, the N₂O emission as well as the community composition and abundance of ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) from fallow paddy field, rape cropping with and without DCD treatment in Taoyuan agricultural ecological experiment station of the Chinese Academy of sciences were measured. The results showed that the addition of DCD significantly inhibited N₂O emissions in fallow paddy field and rape cropping by 36.7% and 23.6%, respectively. The application of DCD in fallow paddy field inhibited the abundance of AOA and AOB by 59.3% and 73.7%, respectively, but only changed the community structure of AOA. The addition of DCD in rape cropping only changed the community structure and inhibited the abundance of AOB. This research showed that DCD application could effectively mitigate the N₂O emissions in fallow paddy field and winter rape cropping under different mitigation mechanisms.