Effects of surface mining on soil nutrient in and around mining area in desert steppe

In order to study the degree and scope of influence of surface mining on surrounding soil factors, the typical mining area and surrounding area of desert grassland in Inner Mongolia, which was located in the ecologically fragile area, were taken as the research area, and soil samples were collected from the mining area and different distances from the mining area to analyze the characteristics of soil nutrient changes in the mining area and surrounding area. The results show that the contents of organic matter (SOM), available potassium (AK) and available phosphorus (AP) in the soil in the study area are at a low level, and the soil quality is poor. The contents of organic matter (SOM), available potassium (AK), available phosphorus (AP) and alkali-hydrolyzed nitrogen (AN) increases significantly with the increase of distance from the mining center(P < 0.05). It indicates that the surface mining affects the accumulation of organic matter and available nutrients in soil, but the pH value and total nitrogen (TN) content of soil do not change significantly. According to the statistical analysis of soil nutrient auto-correlation, total phosphorus (TP), available phosphorus (AP) and available potassium (AK) shows strong spatial auto-correlation, total nitrogen (TN) has moderate spatial auto-correlation, and the spatial auto-correlation of alkali-hydrolyzed nitrogen (AN), organic matter (SOM) and pH value is weak. The soil nutrients in the area 1.0 km to 2.0 km from the mining area and the surrounding area are significantly lower than those in the natural grassland (contrast), and the soil nutrients in the area 5.0 km away from the mining center are basically similar to the natural grassland, indicating that the soil nutrients in the area 5.0 km away from the mining center are basically not affected by mining activities.