中国东部不同气候带森林土壤有机质分解温度敏感性的垂直变异规律与机制: 联网研究

The temperature sensitivity (Q10) of soil organic matter (SOM) decomposition, as an important indicator to descript the response degree of response of SOM its decomposition rate to temperature change, has been widely concerned by scientists and the public. Much effort has been made to improve our understanding on the latitudinal and longitudinal variation (or patterns) inof Q10 in the world. However, few studies to date have tried to investigate its vertical variation, especially lacking on the understanding of the ecological process and underlying mechnisms along the vertical gradients are no fully understoodclear. Furthermore, there is still lacking of no any network researches have conducted to explore the their general mechanisms of Q10 in different climate zones, and it is still not clear whether the underlying mechmisms to control SOM alom along vertical gradient is similar or different with the conterparts of latitudinal and longitudinal gradients. In this work, with the help of continuous automatic variable temperature culturing and continuous automatic measurement technique (a self-dependent innovation technology be authorized patent), we will conduct a comprehensive experiment and analysis for the vertical variations in Q10 among five typical forest vertical gradients (forests in cold temperate zone, warm temperate zone, mid-subtropical zone, south subtropical zone, and tropical zone, respectively) along the North-South Transect in Eastern China (NSTEC). Furthermore, we will analyze the differences of Q10 along the vertical gradient among different climate regions, and reveal the similarities and differences of underlying mechanism (substrate vs. microbes vs. soil texture). Our findings would provide useful information about vertical variations in Q10 and its underlying mechanism, and also provide theoretical basis for scientifically predicting the response and adaptation of forest SOM to future climate change in China’s forests.

土壤有机质分解的温度敏感性（Q10）是刻画其分解速率对温度变化响应程度的重要指标。Q10时空变异性及其内在机制一直是土壤学、生态学和全球变化科学的核心科学问题。科学家已深入探讨了Q10的经纬度格局、影响因素与调控机制；然而，Q10的海拔梯度变异的研究较少，尤其缺乏跨区域、大尺度联网研究，其影响机制是否与经纬度相似，仍不清楚。本项目将采用联网研究思路，沿中国东部南北样带（NSTEC），分别在寒温带、暖温带、中亚热带、南亚热带、热带选择五个典型的垂直梯度明显的森林样带，辅以自主研发的连续自动变温培养+连续自动测试技术，开展垂直梯度的Q10变异性联网研究，深入揭示森林土壤Q10垂直梯度变异规律、不同气候区差异及其内在影响机制的异同（基质vs.微生物vs.土壤质地）。研究结论将改进人们对Q10垂直变异规律及其机制认识的不足，为科学预测中国东部森林土壤有机质对未来气候变化的响应与适应提供理论依据。

土壤有机质分解温度敏感性（Q10）研究是土壤学、生态学和全球变化科学等的长期核心科学问题之一。本项目将通过中国东部森林样带（NSTEC）不同气候带土壤有机质分解速率及其温度敏感性垂直格局的联网研究，辅以自主研发的土壤温度敏感性培养和测试新技术，深入揭示森林土壤温度敏感性垂直变异特征及其区域差异；同时，利用配套测试的土壤质地、土壤有机质组分等数据，深入探讨土壤温度敏感性垂直变异的内在机制，为科学地预测中国东部森林土壤有机质分解对未来气候变化的响应与适应提供理论依据。. 项目主要研究进展与成果包括：1）创新性地发展了土壤有机质分解温度敏感性研究新的培养与测定模式，即连续变温培养与连续测定模式（VCD模式），克服了经典模式的多个主要缺陷；2）开展了VCD模式的多点比对研究，从测试稳定性、数据拟合精度和可重复性等多个角度证明VCD模式的先进性，并将其发表在土壤生物学国际著名期刊《Soil Biology and Biochemistry》，从方法学上引领国类外相关研究；3）通过联网研究，揭示了中国森林土壤有机质分解温度敏感性和最适温度的空间变异规律及其影响机制；4）探讨了模拟氮沉降和酸沉降对温带针阔混交林土壤呼吸及其温度敏感性的影响及其作用机制；5）揭示了寒温带针叶林SOM分解温度敏感性随沼泽水位变化的响应与变化规律。. 通过执行本项目，我们共发表了SCI论文11篇（第一标注5篇）、CSCD论文7篇（第一标注3篇）。其中，部分论文发表在国际相关学科的主流期刊，如《Soil Biology and Biochemistry》、《Trends in Ecology and Evolution》、《Geoderma》、《Catena》、《Plant and Soil》、《Oikos》、《Agriculture and Forest Meteorology》、生态学报等。