中文摘要：

采用氯仿熏蒸浸提法，以宁夏盐池荒漠草原3种典型群落（柠条、沙蒿、短花针茅）类型为研究对象，分析了不同生境（冠下、丛间）和不同土层间（0~5、5~10、10~15cm）土壤理化性质及微生物量——微生物量碳(MBC)和微生物量氮(MBN)的变化特征。结果表明：（1）3种群落土壤微生物量变化差异较大，柠条、沙蒿和短花针茅群落土壤MBC含量分别为77.00~393.18、17.27~221.71和81.05~173.37mg/kg，MBN含量分别为7.59~64.81、1.43~13.95和4.25~22.13mg/kg，MBC和MBN含量均表现为：冠下>丛间，且随土层深度的增加而降低，有明显的“沃岛效应”。（2）群落类型对土壤微生物量碳氮含量的变化有显著影响，3种典型群落类型下土壤微生物量熵（qMB）、碳氮比（C/N）、微生物量碳氮比（MBC/MBN）分别在0.76~4.10、15.02~52.50、5.34~23.07范围内变化，其比值在不同生境和不同土层深度的分布特征有明显差异。（3）3种典型群落类型的土壤MBC与SOC、MBN、qMB具有显著相关关系，土壤C/N与MBC/MBN呈显著正相关关系，表明土壤MBC、MBN具有一定的生物学指示特性，可以作为评价土壤质量的生物学指标。

英文摘要：

Chloroform fumigationextraction were employed to study the content of soil microbial biomass.We choose three typical communities which in Yanchi County of Ningxia desert grassland as the research object,to determine the changing characteristics of soil basic physical and chemical properties and soil microbial biomass carbon and nitrogen,in different soil layers(0-5,5-10,10-15cm)of two soil habitat in different communities(Caragana korshinskii,Artemisia ordosica,Stipa breviflora),The results show that:(1)the study area of C.korshinskii community,A.ordosicacommunity and S.brevifloracommunity of soil microbial biomass carbon(MBC)concentration range were77.00-393.18,17.27-221.71and81.05-173.37mg/kg,soil microbial biomass nitrogen(MBN)concentration range were7.59-64.81,1.43-13.95and4.25-22.13mg/kg,At the same time,the soil MBC and MBN have the same rule the content is continuously reduced with the depth increase which performed“fertile island”and the canopy content is higher than that in plexus in the same depth.(2)Community types had significant effects on the changes of soil microbial biomass carbon and nitrogen contents.Under the3typical communities,the content of the soil microbial biomass(qMB),carbon nitrogen ratio(SOC/TN)and microbial biomass carbon and nitrogen ratio(MBC/MBN)range were0.76-4.10,15.02-52.50and5.34-23.07,respectively.Analysis showed that the ratio in different habitats and different depth of soil layers has obvious difference,besides,the correlation of MBC,MBN,SOC,C/N and qMB in the soil of the3typical communities reached significant or extremely significant level.(3)Considering the soil MBC,MBN and soil nutrient indexes have the same change trend,the soil MBC,MBN can evaluate the quality of the soil as a biological indicator on a degree.