Effects of Different Land Utilization Methods on Soil Aggregate Stability and Organic Carbon Content in Alpine Grassland

[Objective] The soil aggregate stability and differences in organic carbon distribution for Bayanbulak alpine grassland, Xinjiang Wei Autonomous Region under different land utilization methods were analyzed in order to provide a theoretical basis for the evaluation of soil aggregate organic carbon and other ecological functions in this region. [Methods] Three land utilization methods for an alpine grassland in Bayinbuluk were evaluated: reclamation, abandoning farming to grazing, and grazing. Soil aggregates were screened by dry screening and wet screening, mean weight diameter (MWD), geometric mean diameter (GMD), percentage of aggregate destruction (PDA), and soil organic carbon (SOC) contents of soil aggregates were measured and calculated to quantify differences in soil aggregate stability and organic carbon in an alpine grassland under different land utilization methods. [Results] ① Under the three land utilization methods, soil aggregates in an alpine grassland were primarily large aggregates (≥0.25 mm). In the subsurface (10—20 cm) soil, the PDA for the treatment of abandoning farming to grazing was significantly lower than that of the grazing treatment (p0.05). In addition, the soil PDA values of the remaining soil layers in the treatment of abandoning farming to grazing were significantly greater than those observed for the reclamation treatment and the grazing treatment (p0.05). The PDA values of the other soil layers in the reclamation treatment were significantly greater than in the grazing treatment. ② The SOC content, soil aggregate organic carbon content, and the contribution rate of soil aggregates in the treatment of abandoning farming to grazing were significantly less than those in the other treatments (p