秸秆还田配施腐熟剂对稻麦轮作系统氧化亚氮排放的影响及其微生物学机制

稻麦轮作系统是温室气体氧化亚氮（N2O）是重要排放源。秸秆还田显著影响土壤N2O排放。秸秆腐熟剂广泛应用于秸秆还田土壤，具有N2O减排潜力，但其影响土壤N2O排放的微生物学机制尚未系统阐明。本项目拟以长江中下游地区稻麦轮作系统为研究对象，利用静态暗箱-气相色谱法连续两年原位观测秸秆还田配施腐熟剂对土壤N2O排放的减排潜力；采用选择性抑制剂结合底物诱导呼吸法和15N同位素标记技术系统分析秸秆配施腐熟剂对土壤N2O排放关键性微生物过程的影响；通过荧光定量PCR及高通量测序技术揭示土壤硝化和反硝化微生物群落组成的响应规律。本研究有助于深入理解秸秆配施腐熟剂条件下土壤氮素迁移转化过程及其机制，为指导秸秆腐熟剂科学应用及减少农业N2O排放提供理论基础。

The rice-wheat rotation system is an important source of nitrous oxide (N2O) emissions. Straw incorporation has significant effects on N2O emission in soils. The incorporation of straw with microbial inoculants has been increasingly adopted in recent years in China and might have the potential of mitigating N2O emissions. However, the microbial mechanisms underlying soil N2O emissions under this management practice are largely unknown. Based on a 2-year in situ field measurement in a rice-wheat rotation system in the middle and lower reaches of the Yangtze River area, this study will determine the mitigation potentials of N2O emission following the incorporation of straw and microbial inoculants using the static opaque chamber-gas chromatograph method. Additionally, the selective inhibitors combined with the substrate-induced respiration method and the 15N isotope tracer technique will be used to analyze the effects of the incorporation of straw with microbial inoculants on the pathways of N2O production. Lastly, the responses of the abundance and composition of nitrifying/ denitrifying microorganisms will be revealed with the q-PCR and MiSeq amplicon sequencing method, respectively. This study will help to understand the associated mechanisms of soil nitrogen transformation process following the incorporation of straw and microbial inoculants, and provide a theoretical basis for guiding the scientific application of straw-decomposing microbial inoculants and mitigating N2O emissions.