Change of soil microbial biomass carbon in different agroecosystems

The changes of soil microbial biomass carbon in different agroecosystems are studied. The results show that the effect of long-term fertilization of individual N, P is not significant, but the fertilization of manure can enhance the soil biomass carbon and the rate of biomass carbon／organic carbon. At the same time, leguminous can increase the content of biomass carbon in the course of crop rotation in aridland.