[Soil Carbon Restoration and Its Influencing Factors in Coal Mining Areas of Yellow River Basin: A Meta-analysis].

Coal mining has caused notable disturbance and destruction to the ecosystem, leading to intensified regional carbon emissions. Ecological restoration of abandoned coal mines can improve the physical and chemical properties of damaged soil and increase soil carbon storage. Therefore, ecological restoration of coal mine areas is crucial for improving regional carbon sink levels and environments. Currently, most studies on ecological restoration in Chinese coal mining areas are scattered across the major coal-producing provinces in the Yellow River Basin. Its effect on soil carbon sequestration at a basin scale must be crucially elucidated. In this study, we focused on changes in soil physicochemical properties and enzyme activities after vegetation restoration using an integrated analysis method, combined with climate and soil characteristics in the Yellow River Basin's coal mining areas to reveal the major factors affecting soil carbon restoration. Our results showed that： ① Soil physicochemical properties and enzyme activities were improved significantly after ecological restoration； however, some differences were present among different soil layers. ② Soil organic carbon （SOC）, total nitrogen, and alkali-hydrolyzed nitrogen increased by 62.2%, 40.5%, and 36.0%, respectively, showing an overall increasing trend with increasing restoration years. From the perspective of vegetation type, mixed forest had the largest increment in SOC. ③ The increase in nitrogen and phosphorus content improved soil fertility and helped to increase soil carbon input from vegetation litter, thus promoting the restoration of the soil organic carbon pool. In addition, average annual temperature and precipitation along with soil type also played important roles affecting soil C restoration. In the future, based on climate and soil characteristics of specific mining areas, suitable vegetation types should be selected from a perspective of C sequestration to enhance C sink of the whole basin.