中文摘要：

为揭示放牧扰动对冷蒿Artemisia frigida根际土壤微生物量碳（MBC）,微生物量氮（MBN）和基础呼吸等的影响,以内蒙古典型草原为对象,采用氯仿熏蒸浸提法和LI-7000 CO-2/H-2O分析仪,对轻度（LG）和重度（HG）放牧处理后的冷蒿根际土壤进行了MBC,MBN和基础呼吸及其相关性等研究。结果表明：随着放牧强度的增加,土壤MBC,MBN质量分数和基础呼吸速率均呈现先升高后降低的趋势,而且根际土壤值均高于非根际土壤,根际与非根际土壤中微生物量氮质量分数增加幅度高于微生物量碳;冷蒿根际土壤中MBC,MBN和基础呼吸速率与有机质、全氮、碱解氮、全钾呈显著（P〈0.05）或极显著（P〈0.01）正相关。这些土壤养分是影响MBC和MBN等的主要因素。表明放牧处理改变了冷蒿根际土壤中微生物量碳、氮质量分数及基础呼吸速率,轻度放牧能够促使冷蒿根际土壤微生物量和微生物基础呼吸速率显著增加,冷蒿根际能够缓解重度放牧对土壤微生物造成的影响。

英文摘要：

Artemisia frigida is a common plant,esp ecially in degraded grasslands,on the Inner Mongolian steppes.To reveal the effects of grazing disturbance on soil microorganisms of the A.frigida rhizosphere,soil microbial biomass carbon（MBC）,microbial biomass nitrogen（MBN）,and basal respiration and correlation were discussed,by the chloroform fumigation extraction method and the LI-7000 CO-2/H-2O system.Rhizosphere soil of A.frigida（ARS） and non-rhizosphere soil（NRS） under three grazing intensities,no grazing（CK） plot,light grazing（LG） plot,heavy grazing（HG） plot,were chosen as experimental sites in the Inner Mongolian steppes.Results showed that compared with the control group,the soil microbial biomass carbon,nitrogen and basal respiration after light grazing treatment increased by 22.7%,45.0%,17.2%,respectively.These bio-indicators in A.frigida rhizosphere soil were higher than non-rhizosphere soil of A.frigida（P0.05）.Also,the increasing rate of MBN in rhizosphere and non-rhizosphere soil was higher than that of MBC.In the rhizosphere soil of Artemisia frigida,MBC had a positive correlation with organic matter（r=0.737）,total N（r=0.798）,available N（r=0.945）,and total K（r=0.697）.The MBN had a positive correlation with organic matter（r=0.906）,total N（r=0.915）,available N（r=0.937）,and total K（r=0.691）.The basal respiration had a positive correlation with organic matter（r=0.507）,total N（r=0.446）,available N（r=0.805）,and total K（r=0.898）.The light grazing treatment can contribute to a increase to microbial biomass and basal respiration rate.This study provided a theoretical basis for further exploring of ways that A.frigida could help resist grassland degradation.