氧化亚氮（N2O）是一种重要的温室气体，由于当前全球排放量在不断增加，使其在生态环境研究中备受关注。沟渠湿地是我国农业系统N2O排放的重要来源之一，有关沟渠湿地中N2O排放与水位变化的关系还缺乏了解。本项目模拟亚热带农区沟渠湿地，通过野外长期定位试验，利用漂浮静态箱-气相色谱和顶空平衡方法，研究沟渠湿地不同水位下N2O排放特征和水溶N2O浓度及二者内在关系；动态监测影响N2O排放的环境参数，结合多元回归模型，揭示沟渠湿地N2O排放关键驱动因子；采用实时定量PCR和T-RFLP技术，探讨沟渠湿地硝化反硝化微生物种群数量与群落结构对水位变化的响应及其与N2O排放的耦合机制。开展本研究有助于深入认识农业湿地N2O排放规律，同时为我国沟渠湿地系统N2O减排提供科学依据。

Nitrous oxide (N2O) is a powerful greenhouse gas. N2O emission is growing in a global scale, so numerous researches have been focused on global climate change. The vegetated ditch is an important source of N2O emission in agricultural systems. To date few studies have reported the relationship between N2O emission and water level in the vegetated ditch. This research constructs a simulated vegetated ditch, and a long-term field trial will be carried out in the subtropical agricultural areas. Using the static floating chamber-gas chromatography and empty balance method, N2O emission characteristics and dissolved N2O concentrations are studied under different water levels in the vegetated ditches. Then the environment parameters affecting N2O emission are dynamically monitored, and the key environmental factors driving to N2O emissions are revealed through multivariate regression model. By real-time quantitative PCR and T-RFLP technique, the coupling mechanism between the population and community structure of nitrifying and denitrifying microorganisms and N2O emissions under different water levels are studied. To conduct this research helps to understand the law of N2O emissions in agricultural wetlands, simultaneously providing theoretical basis for reduction of N2O emission in vegetated ditches.