Soil physicochemical properties at different degradation levels in alpine meadows of the Tibetan Plateau

This study aimed to explore the evolutionary patterns of soil physicochemical properties at different soil degradation levels and reveal changes in soil quality characteristics during the degradation process in alpine meadows of the Tibetan Plateau. Taking Maqu County with an extension area east of the Tibetan Plateau as the study location, we utilized an indoor detection and analysis to investigate vegetation characteristics and soil physicochemical properties of alpine meadows at different degradation levels. Results showed that vegetation characteristics, including height of aboveground plant communities, coverage, aboveground biomass, and proportion of edible grass, decreased significantly (P < 0.05) as degradation levels intensified. In severely degraded soils, pH, total salt content, water-soluble calcium ions, sulfate ions, and strontium were the highest, whereas effective trace elements, organic matter, and rapidly available potassium were the lowest. Non-degraded, lightly degraded, and moderately degraded soil maintained a certain level of organic matter and pH stability. Total element content did not show a declining trend with increasing degradation. Correlation and cluster analyses showed that the main characteristics of soil quality degradation were pH, total salt content, water-soluble calcium ions, sulfate ions, available iron, and available zinc in alpine meadows. Soil salinization and calcification trends were observed with an increasing degree of degradation. The results provided a theoretical basis for understanding changes in soil nutrient cycling during degradation in the alpine meadows.