氮沉降背景下放牧对草地土壤线虫的影响及其作用机制

Nematodes are an important kind of soil fauna, which is an important part of the process of mineralization of nutrient elements. Nitrogen deposition and grazing both affect soil nematode through altering soil conditions and plant communities, and effects of grazing on nematode could be influenced by nitrogen deposition that changes plant composition and nutrient concentration. So, it will improve our knowledge of maintenance mechanism of the process and function in grassland ecosystem and its response to global change to study the effects of grazing on nematode and its functions under the background of nitrogen deposition. We’ll perform this study on Hulunber grassland with controlled filed experiments, to examine the effects of nitrogen addition and grazing styles (control, cattle grazing, sheep grazing, and mixed grazing) on soil nematode, including community properties (abundance, richness, diversity, composition, maturity index, channel index) and functional properties (enrichment index, structure index, functional footprint) and to analyze the relationship between nematode community and soil carbon and nitrogen cycling. Structure equation modeling (SEM) will be used to examine the effects of nitrogen addition and mixed grazing on nematode through plant community and soil conditions. This work will expand the theories related to ecosystem structure and functions, and provide scientific guideline to grassland management.

土壤线虫是碳氮等关键营养元素矿化的参与者和生态系统重要的分解者。放牧对土壤线虫群落具有重要的调节作用，氮沉降能够通过改变植物群落结构和营养含量而影响家畜采食行为，而有关氮沉降背景下放牧对土壤线虫的作用还缺少相关研究。因此，本项目以温带草甸草原为对象，研究施氮和放牧对土壤线虫多度、丰富度、多样性、物种组成等群落特征以及成熟度指数、通道指数、富集指数和结构指数等功能特征的影响，并通过分析施氮对家畜采食行为的作用，结合放牧对植物生产力、群落结构、营养含量和土壤理化性质的影响，试图阐明施氮和放牧对土壤线虫群落的作用规律，揭示氮沉降背景下放牧调节土壤线虫群落及其功能特征的内在机制。本研究能够加深对草地生态系统功能维持机理及其对全球变化响应机制的理解，为草地管理及生物多样性保护提供重要的科学依据。

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