Response of vegetation characteristics and soil nutrients to grazing in mountain meadows on the north slope of the Tianshan Mountains

Experimental plots with different grazing intensities were set up in mountain meadows on the northern slope of the Tianshan Mountains to study the effects of forbidden grazing (CK), light grazing (LG), and heavy grazing (HG) on vegetation characteristics (plant species composition, biomass, and diversity) and soil physical and chemical properties, to provide a scientific basis for the sustainable utilization of mountain meadows. The results showed that the height, coverage, species richness, and diversity index of montane meadow communities on the northern slope of the Tianshan Mountains decreased significantly with increased grazing intensity (P < 0.05). Under heavy grazing, the dominant perennial grasses and cyperaceae are gradually replaced by poisonous grass and miscellaneous grass. With increased grazing intensity, the biomass of grasses, leguminous forages, sedges, and forbs decreased significantly, aboveground biomass of forbs increased significantly (P < 0.05), and above-ground and below-ground biomass decreased. Soil water content, soil organic carbon, and soil total nitrogen decreased with increased grazing intensity, whereas soil bulk density increased significantly (P < 0.05) and soil total phosphorus and total potassium did not change significantly. The results of redundancy analysis showed that soil water content, bulk density, organic carbon, total nitrogen, and total phosphorus were significantly correlated with vegetation characteristic factors; soil bulk density, organic carbon, and total phosphorus were the main driving factors affecting the vegetation characteristics of the community. It is concluded that grazing has an important impact on the vegetation characteristics and soil nutrient content of mountain meadows, and heavy grazing exacerbates grassland vegetation and soil degradation.