中文摘要：

以青藏高原东北缘天祝高寒地区不同退化草地为研究对象,通过野外调查及室内测定分析,研究了植被特征、微生物量特性、微生物熵及三者之间的相关性。结果表明,随着草地退化程度的加重,植被种类减少、优势种改变,植物群落高度、盖度、地上生物量显著降低（P〈0.05）,土壤微生物生物量碳、氮减少。草地植被地上生物量从轻度退化草地（LDG）到重度退化草地（SDG）减少了88.63%;LDG中微生物量碳、氮（218.90 mg/kg、44.32mg/kg）均显著高于SDG（P〈0.05）,但中度退化草地（MDG）与SDG差异不显著;微生物熵在不同退化草地中的变化规律不明显。草地地上生物量与土壤微生物量呈显著正相关关系（P〈0.05）,与微生物熵呈负相关关系,其中微生物熵与微生物量碳的相关系数相对较高。

英文摘要：

Currently, studies of grassland degradation studies are mainly focused on soil properties, vegetation or soil microbiology separately; studies which consider all of these components are limited. This paper attemp- ted to apply the perspective of systemic theory to provide scientific evidence for grassland degradation. Various degraded grasslands, located at the northeast margin of Qinghai--Tibetan Plateau, were selected for the study. Grassland characteristics were identified and associations between vegetation and soil microorganism properties were investigated using correlation analysis. The results showed that the number of plant species reduced with increased degradation and the dominant species changed. Additionally the height, coverage and aboveground bi- omass of the plant community decreased significantly （P~0.05） with enhanced degradation. Soil microbial carbon and nitrogen content also decreased with enhanced degradation. Aboveground biomass decreases by 88.6% from lightly degraded grassland （LDG） to severe degraded grassland （SDG）. The microbial biomass of carbon （218.90 mg/kg） and nitrogen （44.32 mg/kg） 0.05）, but there was no difference between moderate tient was not affected by degradation. There was a in LDG were significantly higher than those in SDG （P〈0.05）, but there was no difference between moderate degraded grassland （MDG） and SDG. Soil microbial quo- significant positive correlation between aboveground bio-mass and microbial biomass （P〈0.05）.