Abstract: [Objective and Method]Taking the degraded Seriphidium transiliense desert grassland in northern Xinjiang as an example, the soil microorganisms and enzyme activities of the different degraded series (moderate degradation grassland, severe degradation grassland and extreme degradation grassland) are analyzed. [Result]The results showed that the number of bacteria was the largest, which was dominate, and followed by actinomycete and fungi in the degraded grassland. At 10-20 cm soil layer, the differences of the number of bacteria, actinomycete and the total number of microorganisms were notable among the degraded grassland, and the difference of the number of fungi was shown only between severe degraded grassland and extreme degradation grassland. Compared with the moderate degradation grassland and severe degradation grassland, the activities of soil alkaline phosphatase, dehydrogenase and invertase were notablely increased at 0-10 cm soil layer in extreme degraded grassland. Catalase Activity in severe degradation grassland was significantly less than that in the extreme degradation grassland. Urease activity had significant difference only at 10-20 cm soil layer among the degraded grassland. At 10-20 cm ,20-30 cm soil layer,the activity of catalase and dehydrogenase was increased with the increasing of grasslan degradation degree.But urease and invertase activity were degressive. [Conclusion]Therefore, when monitoring the evolution of soil quality of degraded grassland, the sensitive soil biological indicators are: bacteria, actinomycete, alkaline phosphatase, dehydrogenase, invertase.

摘要： [目的]确定北疆退化草地中起重要作用的土壤微生物.[方法]以北疆伊犁绢蒿荒漠退化草地土壤为研究对象,对土壤微生物和酶活性进行分析.[结果]退化草地土壤微生物的组成中,细菌数量最多,占绝对优势,放线菌次之,真菌最少.在10～20 cm土层,草地退化梯度间,细菌、放线菌、微生物总数差异显著,真菌在重度退化与极度退化下差异显著.在0～10 cm土层,极度退化草地土壤碱性磷酸酶、脱氢酶、转化酶的活性均比中度、重度退化草地土壤酶的活性有显著提高.过氧化氢酶活性重度退化草地显著小于极度退化草地.脲酶活性仅在10～20 cm土层各退化梯度间差异显著.在10～20 cm、20～30 cm土层,过氧化氢酶、脱氢酶活性随着草地退化程度的加剧而升高,脲酶、转化酶的活性变化与之相反.[结论]在监测退化草地土壤质量演变时,敏感的土壤生物指标有:细菌、放线菌的数量,碱性磷酸酶、脱氢酶、转化酶活性.