干旱绿洲灌区农田N2O的产生及其微生物机制

Nitrous Oxide （N2O） is one of the main greenhouses, which is closely related to human beings activities. Agricultural soils are the main source for N2O emissions. It is very important to study soil N2O emissions and its microbial mechanism and take more agricultural mitigation measures to mitigate global climate and environmental risk in China. The high frequency observation of soil N2O emissions and its control factors in typical plant systems will be carried out in all year by the long-term field experiment in arid oasis irrigated region. Key functional genes amoA which participates in the process of nitrification and key functional genes nirK, nirS, NosZ which participate in the process of denitrification are regarded as target genes, the community diversity characteristics of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria(AOB) and denitrifying bacteria are to be analysed under the different mitigation measures including optimized water-fertilization, controlled release fertilizers, nitrification inhibitor and no-tillage by applying terminal restriction fragment length polymorphism(T-RELP) and real-time quantitative PCR(QT-PCR) technologies, and it will be cloned, sequenced and constructed a phylogeny tree for key functional genes of typical treatments to analyze domitant microbes. The interactive relationship among soil N2O emissions and its key environmental factors and the community diversity characteristics of soil microbes will be analyzed, and further to understand how soil microbes impacts the process of soil N2O emissions under varying environmental conditions. Effects of different adjustment measures on crop yield will be analyzed to determine which measures is most effective to reduce soil N2O emissions.

农田土壤是人类活动参与的全球N2O主要排放源，在我国开展农田土壤N20排放及其机理和减排技术的研究对缓解因温室气体排放而带来的全球气候和环境效应具有重要意义。本研究拟利用已建立的绿洲灌区农田温室气体长期监测试验，周年高频观测典型作物系统N2O排放特征及其控制因素，以参与硝化过程的关键功能基因amoA和参与反硝化过程的关键功能基因nirK、nirS、NosZ为靶标基因，通过应用末端标记限制性片段长度多态性分析和实时荧光定量PCR技术，分析水肥优化、缓控释肥、加硝化抑制剂和免耕减排措施下硝化古菌、硝化细菌及反硝化细菌的多样性特征，对典型处理关键功能基因进行克隆测序，构建系统发育树，揭示优势微生物种群。分析土壤N2O排放及其关键影响因子和土壤微生物多样性特征三者之间的交互关系，揭示土壤N2O产生的微生物机制。分析不同减排措施对产量的调控效应，为制订减少农田N2O排放综合调控方法提供科学依据。