Effects of Underground Mining on Soil–Vegetation System: A Case Study of Different Subsidence Areas

Abstract

The influence of coal mining subsidence on the surface ecological environment can be characterized as the evolution of a complex system. Examining the ecological damage caused by coal mining subsidence from the perspective of internal soil–vegetation system relationships is important for the ecological protection and restoration of mining areas. We investigated vegetation coverage, surface soil water and nutrient content, and vadose zone soil moisture in uniform and nonuniform areas of coal mining subsidence. Subsidence reduced vegetation coverage, surface soil moisture and nutrient content, and vadose zone soil moisture while increasing their spatial variability. These effects are more pronounced in areas with nonuniform subsidence. Subsidence also reduced the degree of soil–vegetation system correlation, which was also more pronounced in areas of nonuniform subsidence. Furthermore, a higher degree of soil–vegetation correlation was linked to decreased variability in soil moisture and nutrient content. Areas of nonuniform subsidence were characterized by greater preferential flow during rain infiltration, which contributed to the spatial variability of soil moisture and nutrient content and damage to vegetation growth. Our findings revealed that coal mining subsidence reduces both the quality of environmental factors and the degree of internal correlation between these factors, of which the preferential flow effect is an important underlying mechanism. These findings provide a theoretical basis for ecosystem management and the restoration of land damaged by coal mining subsidence.