Abstract: By using dilute plate counting and chloroform fumigation methods, this paper studied the quantitative characters of soil microbes, microbial biomass, and organic matter under the vegetations Kobresia tibetica, K. pygmaea, K. humulis, grass, forb, and Potentilla fruticosa shrub in alpine meadow ecosystem. The results showed that in 0-40 cm soil layer, the numbers of bacteria and actinomyces and the contents of microbial biomass C and organic matter were the highest in K. tibetica meadow, while the fungal number was the highest in P. fruticosa shrub meadow. The microbial biomass C and organic matter contents in K. tibetica meadow were obviously higher than those in the other five meadows. Path analysis indicated that there were varied degrees correlations among different bio－environmental factors, and the numbers of soil microbes as well as the contents of soil microbial biomass C and organic matter had significant correlations with soil moisture content, indicating that soil moisture could be a key factor regulating the metabolism of soil microbes and the transformation of substances in alpine meadow ecosystem.

Key words: Changhaishan, Wudalianchi, Volcanic ash soil, Zero point of charge, Long-rang tropospheric eolian dust