Spatial Patterns and Key Drivers of Soil Organic Carbon in Northeastern China's Discontinuous Permafrost Zone

Based on field survey data of soil organic carbon (SOC) content and remote sensing datasets including climate, vegetation and terrain, this article analyzed the controlling factors of SOC and its spatial distribution in the 0–20 cm layer of the Huma River Basin in Northeastern China using the geographically weighted regression (GWR) model and the ordinary least squares (OLS) regression model. The results show that the SOC content in this area ranged from 13.2 to 167.2 g/kg, the GWR model outperformed the OLS model, and the GWR model is a useful tool for mapping SOC in discontinuous permafrost regions. The results further show that SOC was negatively correlated with air temperature and slope, but positively correlated with precipitation and elevation. The spatial consistency of SOC with the topography in this basin indicated an important role of the latter in controlling the SOC distribution. In addition, climate warming likely promotes SOC mineralization, while wetting favors the preservation of SOC in the southern boundary of high-latitudinal permafrost regions.