放牧对草地土壤微生物的影响

土壤质量是草地生态系统生产力可持续发展的关键所在。健康的土壤必定拥有丰富的物种多样性、活跃的生命体、高效的内部养分循环及较好的抗干扰能力。土壤微生物作为土壤系统中各种生物进程的主要推动者，其作用不可小觑。因此，我们可以利用土壤微生物的数量、群落结构和多样性等特征监测土壤质量。本文综述了放牧对草地土壤微生物数量、生物量、群落结构和多样性的影响。指出通过了解土壤微生物与放牧行为间的关系，如何评估土壤质量，选取适宜的放牧梯度，完善草地管理模式，并介绍了土壤微生物群落结构和多样性研究方法的利弊。解决两个关键问题：1）土壤微生物的各种特征是如何响应放牧行为的。2）如何通过这些指标评价土壤质量，然后提出合理的放牧模式，改善和维护草地的生产力。

The impacts of grazing on the soil microorganism population of grassland

Soil quality is crucial to sustainable development of grassland ecosystems and to their productivity. Healthy soil must have rich species diversity,active microorganism populations,an efficient internal nutrient cycle and good buffering against disturbance.Soil microorganisms are the main driver of various biological processes and are therefore very important in soil systems.Hence,soil microbial community characteristics such as population numbers,community structure and species diversity can be used as a measure of soil health. The present paper summarizes the effects of grazing on the grassland soil microbial populations,community structure and diversity.We propose that it is essential to understand the impact of grazing management on soil microorganisms.A methodology is introduced for evaluation of soil health,and selection of a suitable grazing level to improve grassland management,and the advantages and disadvantages are discussed.Two key ques-tions are addressed;namely the responses of the soil microbial community to grazing activity,and how to use these indicators to evaluate soil quality and propose a reasonable grazing practice to sustainably improve the productivity of grassland.