南亚热带典型人工林土壤氮转化关键过程的制约因素及其调控机制

土壤N作为植物生长和森林生态系统初级生产力的最主要限制因子之一，其转化过程的改变会导致整个森林生态系统生产力和物质循环发生变化，从而影响全球气候变化。但土壤N的转化过程由于受一系列生物和非生物因子相互作用的影响，是一个极其复杂的过程。本研究以揭示人工林土壤N转化关键过程的制约因素及其调控机制为目标，选择南亚热带典型人工林类型作为研究对象，采用野外长期监测和室内控制试验相结合的方法，重点探究：（1）不同人工林类型土壤N转化的变化规律及其微生物调控的主要路径和关键控制因子；（2）特定的微生物类群与土壤N转化之间的关系；（3）关键生物和非生物因子在调控土壤N转化中的作用；（4）典型人工林土壤N库各组分的分布规律。为定向调控土壤N的转化过程，提高土壤N的有效性和降低其对环境负面效应的树种选择、经营模式和措施等方面提供重要科学依据。

Soil nitrogen as one of the main limiting factor in plant growth and forest ecosystem primary productivity, the changing of forest soil nitrogen transformation processes will cause the entire forest ecosystem productivity and material circulation, then change the global climate. However, soil nitrogen transformation in forest is an extremely complex process because of the interactive effects of biotic and abiotic factors. The objectives of this study are reveal the constraints and regulation mechanisms on the key process of soil nitrogen transformation in typical forests in the south subtropical China. By combining long-term field investigations and laboratory controlling experiments, our objectives are to explore: (1) the critical factors and main regulatory pathway of soil microbial community on the variation of soil nitrogen transformation in different forest types; (2) the relationship between specific microbial groups and soil nitrogen transformation process; (3) the roles and potential mechanisms on the regulation of soil nitrogen transformation by key biotic and abiotic factors; (4) the distribution of each component in soil nitrogen pools. The outcomes of this study is anticipated to provide scientific basis for adjustment of nitrogen transformation process, improvement of nitrogen utilization efficiency and elimination of its negative effects thought tree species selection, forestry manage model and measures.