土壤温室气体的时空变异性及尺度效应

Soil respiration is the second largest carbon source from land to the atmosphere. Therefore, changes in soil greenhouse gases can significantly affect the current atmospheric levels of greenhouse gases, which affect the climate change. On the other hand, the soil has a huge capacity of carbon sequestration. However, soil greenhouse gases, distributions of soil carbon and nitrogen, and the related processes are with highly temporal and spatial variability and scale dependency. Therefore, it is a huge challenge to quantitatively describe soil carbon and nitrogen cycling, soil greenhouse gas distributions, and their impact on the climate change. In this project, we will study effects of the key soil physical, chemical, and biological properties and processes on spatial and temporal variability and scale dependency of soil greenhouse gases. We will develop statistical and theoretical models to characterize the variability and scale dependency of soil greenhouse gases. Economic analysis will be combined into the study of soil carbon sequestration and soil greenhouse gases to provide better research methods (e.g., the design of optimal sampling strategy and selection of key parameters) and wider research horizons. This study will provide a theoretical basis to determine the best land management practices to increase soil carbon sequestration, reduce emissions of soil greenhouse gases, and to have the integrated ecological, environmental, and economic benefits.

土壤呼吸是从陆地到大气中的第二大碳源，因此，土壤温室气体的变化能显著地影响当前大气中温室气体的含量，从而影响气候变化，而另一方面土壤具有巨大的碳汇能力。然而，土壤温室气体和土壤的碳、氮分布及其相关过程具有高度的时空变异性和尺度效应，从而为定量描述土壤碳、氮循环过程，土壤温室气体的变化规律及其对气候变化的影响带来巨大挑战。该项目将深入研究影响土壤温室气体的时空变异性及尺度效应的关键土壤物理、化学和生物特性和过程，建立表征土壤温室气体的时空变异性及尺度效应的统计模型和理论模型，将经济分析结合到土壤温室气体和土壤碳汇的研究中以提供更好的研究方法（如设计最佳采样策略、选择关键参数等）和跨学科的综合视野。这一研究将为制定最佳土地管理策略，以达到提高土壤固碳能力、减少土壤温室气体排放的综合生态、环境和经济效益提供理论基础。

土壤呼吸是从陆地到大气中的第二大碳源，因此，土壤温室气体的变化能显著地影响当前大气中温室气体的含量，从而影响气候变化，而另一方面土壤具有巨大的碳汇能力。为了表征土壤温室气体和土壤的碳、氮分布的高度时空变异性和尺度效应，定量描述土壤碳、氮循环过程，我们建立了全球生态系统呼吸数据库，并开展了大量实验室和较小尺度的田间试验和数值模拟实验。通过这一项目，我们在陆地生态系统CO2平衡过程与气候变化的互反馈研究，陆地生态系统呼吸温度敏感性及影响因素，不同活性土壤碳库呼吸的温度敏感性及土壤呼吸激发效应研究，生物炭电化学活性对反硝化作用和N2O排放的影响，以及提高土壤固碳、减少土壤温室气体排放的管理策略等方面都取得具有一定创新性的研究成果。基于这些成果，已发表41篇学术论文（包括39篇SCI论文）。这些研究成果为制定最佳土地管理策略，以达到提高陆地生态系统的综合生态、环境和经济效益提供理论依据。