不同种类秸秆添加对稻田NH3挥发的影响机制OA北大核心CHSSCDCSTPCD

The incorporation of straw into paddy fields has an impact on the volatilization of NH3,but the underlying emission patterns and regulatory mechanisms require systematic investigation.In this study,using the Nanjing 46 rice variety and the original soil from a typical single-season rice paddy in the Taihu region,we employed the continuous airflow enclosure method to monitor NH3 volatilization flux,soil physicochemical factors,and rice yield under the application of three types of straw(rice straw:RS;wheat straw:WS;corn straw:MS)at two different application rates(straw weight:soil weight=0.5％and 0.8％).Additionally,we used molecular biology techniques to couple environmental factors with the abundance of nitrogen cycling-related functional microorganisms to reveal the response mechanisms of NH3 volatilization to different types and application rates of straw,and to decipher the key factors influencing this process.Consequently,we identified the most suitable type and application rate of straw for returning to rice paddies to achieve optimal yield increase and emission reduction.The experimental results show that the type of straw and the interaction between the type of straw and its application rate have significant impact on NH3 volatilization in paddy soil.Overall,compared with CK,the change in NH3 volatilization due to straw application ranges from-33.2％to 27.3％.Different types of straw have different effects on NH3 volatilization in paddy soil.At low application rates,compared with CK,the application of RS and WS has no significant effect on NH3 volatilization,while the application of MS significantly increases NH3 volatilization by 21.1％;at high application rates,the application of RS significantly reduces NH3 volatilization by 33.2％.Different straw application rates also have different effects on NH3 volatilization in paddy soil.Under RS and MS treatments,the NH3 volatilization in paddy fields decreases by 31.2％and 32.8％,respectively,with the increase of application rate,while WS treatment shows the opposite trend;under the interaction of different straw types and different application rates,RS-0.8 treatment significantly reduces NH3 volatilization in paddy soil by 33.2％.The pH of paddy water,total nitrogen(TN)concentration,soil microbial biomass carbon content(MBC),and the abundance of soil ammonia-oxidizing archaea(AOA)and ammonia-oxidizing bacteria(AOB)communities are the main influencing factors causing differences in NH3 volatilization in paddy soil under different straw types and amounts.Compared with other treatments,RS-0.8 treatment significantly increases the abundance of soil AOA and AOB communities and significantly reduces the TN content of paddy water.The comprehensive effect significantly reduces NH3 volatilization in paddy fields by 33.2％and significantly increases rice yield by 22.9％.Taking into account both NH3 volatilization and rice yield,the application of rice straw at a rate of 0.8％in the rice planting system with straw returning shows the best emission reduction and yield-increasing effect.