Study of NN2OO Emission at Drawdown Area in Zhuyi River, Three Gorges Reservoir

三峡成库后，根据其“蓄清排浑”的运行方案，水库周围形成垂直落差达30 m、总面积达348.93 km2的消落带。三峡水库消落带具有湿地生态系统的诸多特征，但在“反季节性”水库干湿交替和近岸农民高强度垦殖等多重因素影响下，其生态特征与过程甚为复杂，特别是温室气体产生和排放目前研究仍有限，消落带N2O释放的主要影响因素也尚不明晰。本研究选取三峡上游支流朱一河河湾消落带为研究对象，通过1年的野外试验，对N2O排放通量和环境氮素的变化进行了现场连续监测。结果表明，消落带是三峡上游支流朱衣河河湾温室气体N2O的重要排放源，夏季是N2O排放最大的时期；温度和土壤含水率是朱衣河河湾消落带N2O排放的主要影响因素，N2O排放通量随温度的升高呈指数增加，土壤含水率在35%~60%之间，N2O排放显著。 There are some drawdown areas around the three gorges reservoir. Drawdown areas of the three gorges reservoir have many characteristics of wetland ecosystem. However, the ecological cha-racteristics are very complex. The greenhouse gas production and emissions are seldom studied in this zone. This study selected the drawdown area in three gorges upstream tributaries Zhuyi River as the research object. The N2O emission flux and the change of environmental nitrogen had been studied continuously. The results showed that the drawdown areas were the important source of N2O emission in Zhuyi river and summer was the biggest period of N2O emission. Temperature and soil moisture content were the main influencing factors of N2O emissions in drawdown area.