Influence of Grazing Intensity on the Soil Organic Carbon and Microbial Biomass Carbon of Meadow Steppe in Zhaosu Area

The influence of grazing intensity,including the control(0 cattle/hm2),light grazing(0.38 cattle/hm2),moderate grazing(0.64 cattle/hm2) and heavy grazing(0.90 cattle/hm2) on the soil organic carbon,soil microbial biomass carbon and soil microbial quotient in Zhaosu Meadow Steppe by plot control grazing experiment during 2-years was studied.The result showed that during the short grazing period the content of soil microbial biomass carbon and soil microbial quotient of 0-30 cm appeared the trend of first increasing then decreasing with the increase of grazing intensity.The grazing intensity has smaller influence on content of soil organic carbon under grazing in a short period(P0.05),but it had more significant influence on soil organic carbon,which indicated that the response to grazing of soil microbial biomass carbon was more sensitive than that of soil organic carbon.The content of soil microbial biomass carbon under moderate grazing was higher than that of CK,light grazing and heavy grazing(P0.05),and the soil microbial biomass carbon content of 0-10 cm,10-20 cm,20-30 cm in proper sequence was 1074.77,667.94 mg/kg and 392.54 mg/kg.Whether grazing or not,the content of soil organic carbon,soil microbial biomass carbon and soil microbial quotient all significantly decreased with increase of soil depth.