Analysis of Soil Carbon, Nitrogen and Phosphorus Storage and Sequestration Effects in Alpine Grassland with Different Degradation Levels in Maqu County, China

Soil nutrient storage and sequestration effects are closely related to the stability of alpine grassland ecosystems, and the study of soil nutrient storage and sequestration effects in alpine grasslands with different degradation levels is of great significance to the recovery of alpine grassland vegetation. On this basis, four alpine grasslands with different degrees of degradation (non-degraded, lightly degraded, moderately degraded, and heavily degraded) were selected in Maqu County, Gannan, and soil samples were collected from 0–10, 10–20, 20–40, and 40–60 cm, respectively, and analyzed for nutrients in terms of storage and sequestration effects. The results showed that soil water content decreased with increasing degradation, while soil pH, bulk density, and conductivity tended to increase. The storage and sequestration effects of soil organic carbon decreased with increasing degradation. And the storage and sequestration effects of soil total nitrogen and total phosphorus were smallest for moderately degraded soils in the 10–60 cm soil layer. Soil water content and soil bulk density were co-influences on soil organic carbon, total nitrogen, and total phosphorus storage. For the soil organic carbon sequestration effect, soil total nitrogen sequestration effect and soil pH were the two most important influencing factors, and the soil total nitrogen and total phosphorus sequestration effect were greatly influenced by soil organic carbon sequestration effect. In addition, soil bulk density was also the main influencing factor of soil total nitrogen sequestration effect, and the impact of soil total nitrogen sequestration on soil total phosphorus sequestration was also greatly influenced.