Response of Plant Diversity and Soil Nutrient to Grazing Intensity in Kobresia pygmaea Meadow of Qinghai-Tibet Plateau

The effect of grazing intensity disturbance on plant diversity,soil chemical properties,and soil available microelements characteristics of Kobresia pygmaea meadow community in Qinghai-Tibet plateau was studied to provide scientific basis for Kobresia pygmaea meadow ecosystem protection and restoration.Results showed that vegetation coverage,number of species,plant diversity and aboveground biomass were significantly decreased along with the increasing of grazing intensity.There was significant difference between heavy grazing and control(P0.05),while no significant difference between moderate grazing and control.The influence of grazing disturbance on soil chemical properties decreased soil organic matter,available nitrogen,total phosphorus and available phosphorus in 0~30 cm soil layers,but there was no significant difference between moderate grazing and control.Total phosphorus and available phosphorus contents of soil under moderate grazing was significantly increased in 10~20 cm soil layers.The contents of soil available microelements were obviously increased with the increasing of grazing intensity(P0.05).The contents of soil available trace elements was ordered as FeMnZnCu.These results suggested that moderate grazing was an effective way to protect plant biodiversity and improve grassproductivity of Kobresia pygmaea meadow.