Abstract:【Objective】 Explore the impact of grazing enclosure on plant community structure and soil water conservation function of alpine steppe on the Qinghai Lake region, and It is significant to accurately evaluate the effect of grazing enclosure on the restoration of degraded grassland in Qinghai Lake. 【Methods】 Four sample plots (free-grazing, enclosure for 4 years, enclosure for 7 years and enclosure for 14 years) were set in the alpine steppe on the north shore of Qinghai Lake and the effects of enclosure measures on the number of vegetation species, biomass, functional groups, soil bulk density, water holding capacity and porosity was analyzed by the combination of field monitoring and indoor experiments in present research. 【Results】 (1) With the increasing of enclosure times, the number of species in the alpine steppe on the north shore of Qinghai Lake was decreased, the vegetation cover, above-ground biomass, below-ground biomass was first increased and then decreased. The percentage of grasses in the community gradually increased, which improved the feeding value of plant on the north shore of Qinghai Lake. (2) The effects of grazing exclusion on soil moisture characteristics of alpine steppe on the north shore of Qinghai Lake are mainly concentrated in the 0-20 cm depth. With the extension of grazing exclusion years, soil bulk density at 0-20 cm decreased gradually, soil saturated water holding capacity, capillary water holding capacity, field water holding capacity and total porosity at 0-10 cm first increased and then stabilized. (3) Soil bulk density is the most important soil water characteristic factor which affecting the vegetation community structure on the alpine steppe in the north shore of Qinghai Lake. 【Conclusion】 Short-term grazing exclusion measures are conducive to the recovery of degraded grassland ecosystems along the north shore of Qinghai Lake, and it was an effective measures to improve the degradation of grasslands in this area, but scientific grazing exclusion should be carried out to avoid prolonged grazing exclusion.
