The study of soil microbial biomass and soil enzyme activity on different grassland in Hulunbeier, Inner Mongolia.

In this study,5different types of grassland(Filifolium sibiricumsteppe,Stipa baicalensis steppe,Leymus chinensis steppe,Stipagrandis steppe,Stipa kryrowi steppe)in Hulunbeier were selected as the research object to analyze the variation of the soil physicochemical characteristics,soil microorganism,soil microbial biomass,soil enzyme activity and the inter-relationship among them.The results showed that the number of microorganisms in different types of grassland were in the same changing trends:bacteriaactinomycetes fungi,but the number of each microorganism and composition reduced significantly(P0.05).The bacteria number in 5different types of glasslands was L.chinensis steppeS.baicalensis steppeS.kryrowi steppe F.sibiricumsteppeS.grandis steppe,the fungi number was S.kryrowi steppeL.chinensis steppe F.sibiricumsteppeS.baicalensis steppeS.grandis steppe,the actinomycetes number was F.sibiricum steppeS.kryrowi steppeL.chinensis steppeS.baicalensis steppeS.grandis steppe.Soil microbial biomass C,N(SMBC,SMBN)reduced significantly(P0.05)in different grasslands.The microbial biomass carbon and nitrogen in F.sibiricumsteppe soil were significantly higher than others(P0.05),soil microbial biomass C and N in S.grandis steppe and L.chinensis steppe were lower.Results also showed that soil activitiey reduced significantly(P0.05)in different grasslands with 0-10cm higher than 0-20cm in the vertical distribution.Soil activitoes of catalase and invertase activities of F.sibiricumsteppe were significantliy higher than S.grandis steppe,S.baicalensis steppe;Soil urease activity of S.kryrowi steppe was the highest and significantly different fromS.grandis steppe,F.sibiricumsteppe,soil phosphatase activity in L.chinensis steppe was the highest and significantly different from others.Correlation analysis indicated that soil microbe quantity,soil microbial biomass,soil enzyme activity and soil physicochemical characteristics in different grasslands had different degrees of correlation.The regression formula indicated that soil microbial biomass C increased with soil moisture,bacteria quantity but decreased with soil phosphatase activity;soil microbial biomass N increased with soil hydrogen peroxidase activities,but decreased with soil phosphatase activity and soil bulk.