With global urbanization and industrialization, environmental pollution and food safety problems caused by soil heavy metal pollution occur frequently. To realize the safe utilization of cultivated land resources in high-risk areas of heavy metal pollution, we present an approach to safe utilization classification and management in this study. A typical agricultural area around industrial and mining enterprises located in the economic belt of the Yangtze River Delta was chosen as the research area with cultivated soil as the research object. A total of 1,139 geochemical survey sampling sites and soil survey data were used for this research. Initially, the potential ecological risk index was used to assess the potential ecological risk of heavy metals in cultivated soil, and key soil physical and chemical indicators were chosen to assess soil resilience. Next, the safe utilization classification of cultivated land was carried out by combining the potential ecological risk of soil heavy metals with soil resilience. Then, the specific classification management strategy was developed according to ecological risk factor types and crop types. The results showed that the production and operation activities of industrial and mining enterprises in the study area contributed significantly to soil Cd and Hg pollution, and the potential ecological risk of heavy metals in the surrounding soil was high. The soil resilience of cultivated land in the study area was generally not high. The clay content and cation exchange capacity (CEC) were the main strong restrictive indicators, while CaO, soil organic carbon (SOC), and pH were the main medium restrictive indicators. Natural conditions such as topography, hydrogeology, and soil-forming parent material differed by region, resulting in different restrictive factors. There were 16 safe utilization types in the study area. Different management strategies were proposed based on various soil potential ecological risks, soil resilience, ecological risk factor types, and crop types. This study can offer fresh perspectives on the safe utilization classification and management of land resources in high-risk areas of soil pollution and serve as a reference for sustainable intensification.

In order to investigate the changes in soil enzyme activity and their influencing factors in coal mining subsidence areas with high underground water levels, in this study, we collected soil samples at different depths (SL: 0–20 cm; ML: 20–40 cm; DL: 40–60 cm) in a deep coal seam subsidence area (T1), a shallow coal seam subsidence area (T2), and control non-subsidence areas (W1 and W2) in eastern China. Soil physicochemical properties and enzyme activities were determined, and the mechanism of the latter’s response to coal mining subsidence was investigated based on correlation analysis, redundancy analysis, and structural equation modeling. The results show the following: (1) In the coal mining subsidence areas, the soil pH value (pH), soil available nitrogen (AN), available phosphorus (AP), available potassium (AK), and soil organic matter (SOM) contents were lower than those in the non-subsidence areas, while the soil water content (SWC) and bulk density (BD) were higher than those in the non-subsidence areas and increased with depth. (2) The activities of soil urease (URE), sucrase (SUC), alkaline phosphatase (ALP), and catalase (CAT) gradually decreased with depth and were all lower than those in the non-subsidence areas; the largest decreases with respect to the latter were 24.33%, 18.73%, 38.89%, and 5.88%, respectively. (3) The soil nutrient environment had a highly significant and direct positive effect on enzyme activity, with AN, AP, and SOM contents having the greatest impact. (4) Soil BD had a highly significant and direct negative effect and an indirect negative effect (by affecting nutrients) on enzyme activity. The results of this study on the effects of soil physicochemical properties on enzyme activity provide a basis for the ecological restoration of mines.

变化和驱动 土壤的机理 地下水位高的煤矿沉降区微生物群落 水平徐瑞萍a，b，#， 宋温a，b，#, 张金宁a，b， 江旭子a，b, 张慧忠a，b， 李新举a，b，*, 李俊英a，b，*a 山东农业资源与环境学院 泰安大学，271018，中华人民共和国b 国家土壤高效利用工程技术研究中心 和 Fertilizer Resources， Taian， 271018， 中华人民共和国* 通讯作者。山东资源与环境学院 农业大学， 泰安， 271018， 中华人民共和国E-mail地址： ljy3069@163.com （J. Li）， lxj0911@126.com （X. Li）#两位作者对这项工作做出了同等贡献，并且 应被视为共同第一作者