基于高频协同观测的土壤CO2、CH4、N2O通量变化耦联关系及解耦机制研究

The process of soil CO2, CH4 and N2O flux is a hot topic in the field of climate change research. At present, there is already a deep understanding of the single greenhouse gas flux and the environmental regulation mechanism. The ecological system management programme selected based on a single greenhouse gas emission mechanism may cause the increase of the other two kinds of gas emissions. To avoid this, the relationship between the three gas fluxes, namely the coupling relationship, should be studied. There are obvious differences in meteorology and soil conditions between Changbaishan and Dinghushan forest ecosystem. In this study, we will take these two ecosystems as examples to obtain high-frequency flux data using soil greenhouse gases automatic multi-channel continuous monitoring system. Taking correlation coefficient as an indicator of the coupling relationship, we will analyze the dynamic changes of the coupling relationship on different time scales, summarizes the environmental conditions when coupling and decoupling occur, and identifies the integrated regulation mechanism of coupling/decoupling of moisture, temperature and soil parameters. Using pot experiment in lab, explores the carbon and nitrogen cycle processes and mechanism underlying the flux coupling and decoupling. Study on the coupling relationship between fluxes is an enrichment of the mechanism of carbon and nitrogen cycle. Moreover, it can provide theoretical support for the trade-off management to reduce the total emissions of the three greenhouse gases.

土壤CO2、CH4、N2O通量过程机理是气候变化的热点研究领域。目前对单种温室气体排放的过程机理已形成较为深入的认识。但仅基于单种温室气体排放机理选择的生态系统管理方法，可能导致其他两种气体排放量升高。为避免这一点，需要研究三种温室气体通量间关系即耦联关系。长白山与鼎湖山森林生态系统的气象及土壤等条件具有明显差异，本研究将以这两个生态系统为例，利用土壤温室气体全自动多通道连续监测系统获取高频通量数据，以土壤通量间相关系数作为耦联关系的指示性指标，揭示通量间耦联关系在不同时间尺度上的动态变化；归纳发生耦联与解耦时的环境条件；辨析水热、土壤等环境条件对耦联/解耦的综合调控机制；结合控制实验，探讨引起耦联与解耦的碳氮循环过程机制。对通量间耦联关系的研究，既是对碳氮循环过程机理的丰富；也可为制定减少三种温室气体总排放的权衡式管理措施提供理论支撑。