Effect of Grazing Disturbance on Soil Microbial Biomass and Respiratory Quotient in Mountain Forest of Arid Valley Ecotone in Upper Reaches of Minjiang River
This study focused on the responses of microbial biomass and respiratory quotient of 4 vegetation types to grazing disturbance at the upper reaches of Minjiang River. These vegetations were Robinia pseudoacacia, Artificial Poplar, Grassland and Berberis shrub. Three grazing disturbance intensity were set with different distances from sample plots to grazing-path. Then analyzed soils under different treatments. The results showed that at different vegetation types, the values of soil organic carbon(SOC) and microbial biomass corbon(MBC) decreased with the increasing grazing intensity; the values of qCO2 of surface soil increased by 15.14%~100.54% with the increase of grazing pressure(except moderate disturbance in shrubs). These data illustrated that grazing disturbance accelerated the turnover rate of microorganisms, decreased the utilization rate of SOC, increased emission content of CO2 and decreased preserving rate of soil carbon.