| The experiment was conducted to determine the influence of banning grazing on alpine meadow soil organic carbon, physio-chemical properties and enzyme activities at Ice Valley, Qilian Mountain. The results showed that the vegetation coverage, soil biomass and organic matter content of alpine meadow soil were decreased significantly after grazing for three years. Organic matter content, organic carbon density, total porosity, aggregate, field capacity, NPK content and enzyme activity at 0～20 cm layer was decreased, and soil bulk density, CaCO3 and soluble salt content was increased. Compared with grazing, the soil bulk density, CaCO3 and soluble salt content at 0～20 cm layer in area of grazing prohibition were increased by 14.15%, 6.35%, and 1.27%, and organic matter content, organic carbon density, total porosity, aggregate, and field capacity by 29.76%, 22.82%, 9.45%, 6.49%, and 7.69%, respectively; while the urease, sucrase, phosphatase and calatase activities and total NPK was reduced by 33.77%, 26.11%, 42.00%, 29.31%, 25.97%, 15.56% and 12.17%, respectively. In conclusion, the influencing depth of grazing on organic carbon, soil bulk density, total porosity, field capacity decreased, soluble salt content, NPK and enzyme activity was 0～20 cm soil depth, whereas that on aggregate was 0～40 cm soil depth. |