Relationship between plant communities, characters, soil physical and chemical properties, and soil microbiology in alpine meadows.

This study examined the relationship between soil physical and chemical properties,soil microbial quantity,soil enzyme activities,and ecosystem function in alpine meadows.There were obvious discrepancies in the soil characteristics of different vegetations.Soil bulk density,soil moisture,soil organic matter,soil total nitrogen and soil available nitrogen were significantly different in the 0-40 cm soil layer in Kobresia tibetica swamp meadow from those in a K.humlis meadow,K.pygmaca meadow,and a Potentilla froticosa shrub.The changes in community composition and plant species diversity resulted from variations in soil properties.Bacterial and fungal quantities showed a positive linear correlation with community biomass in four grasslands(P0.05),while actinomycete quantities showed no significant relationship with community biomass.The quantity and composition of soil microbes were influenced by different community biomass in different vegetations.Although aboveground biomasses showed significant correlation with different enzyme activities.These enzymes(urease,protease and phosphatase) were involved in soil carbon and nitrogen cycles.Soil enzyme activities influenced not only community biomass,but also plant species diversity(plant species richness) and community composition.