Spatial pattern and its driving forces analysis of soil available nitrogen, phosphorus, and potassium in semi-arid grassland surface coal mining areas

Mining activities not only provide a large amount of material basis for socio-economic development but also cause great damage to the environment. It is of great significance to study the spatial variation characteristics of soil Available Nitrogen (AN), Available Phosphorus (AP), and Available potassium (AK) in mining areas for land reclamation and ecological protection. Currently, research on soil AN, AP, and AK in mining areas is lacking in large-scale survey, sampling, spatial pattern, and driving force research for surface coal mines in semi-arid grassland areas, and it is not possible to comprehensively grasp the distribution characteristics and driving forces of soil AN, AP, and AK in surface coal mines. Given this, this study took the Shengli Coal Field in Xilinhot City, the hinterland of Xilingol Grassland, as an example to study the spatial pattern and driving forces of soil AN, AP, and AK in the semi-arid grassland surface coal mining areas. The results showed that: (1) There was no strong spatial correlation among AN, AP, and AK in the soil of the study area, and the spatial pattern heterogeneity was strong. The content of AN, AP, and AK in southeast soil was relatively low. (2) The influence degree of each factor on the spatial pattern of AN was ranked as follows: NDVI > Agriculture > Water > Town > Mining > Industry; (3) The influence degree of each factor on the spatial pattern of soil AP was ranked as follows: NDVI > Mining > Water > Industry > Town > Agriculture; (4) The influence degree of each factor on the spatial pattern of soil AK was ranked as follows: NDVI > Town > Agriculture > Water > Mining > Industry; (5) The interaction between two factors presented two relationships: nonlinear enhancement and dual-factor enhancement. The interaction between various factors was higher than that of a single factor.