Effect of reclamation years on soil physical, chemical, bacterial, and fungal community compositions in an open‐pit coal mine dump in grassland area of Inner Mongolia, China

Abstract

Understanding the process of changes in substrate physical, chemical, and biological properties is critical for vegetation ecosystem reconstruction of open‐pit coal mining dumps. However, the relationships of soil chemical, biological, bacterial, and fungal characteristics in open‐pit coal mining dumps in grassland area are still unclear. The purpose of this study is to understand the changes and relationships of soil physic‐chemical, bacterial, and fungal properties under the reclamation time series of open‐pit coal mining dumps. Soil samples were collected from the waste dump reclaimed after 2, 5, 10, and 15 years in Shengli West No. 2 open pit coal mine in Inner Mongolia, China, and the surrounding natural grassland was set as a control at 0–10 cm and 10–20 cm. Soil pH, electrical conductivity (EC), soil organic matter (SOM), nutrient properties, bacterial, and fungal community structures were measured in the waste dump reclaimed after 2, 5, 10, and 15 years. The results showed that soil pH was decreased at 0–20 cm in the waste dump while SOM was increased by 1.2 times in 0–10 cm reclaimed after 15 years than that after 2 years. Soil EC was decreased by 55.5% and 58.3%, respectively, in 0–10 cm and 10–20 cm, respectively, after 10 years than that after 2 years. Soil available nitrogen, available phosphorus, and available potassium were 97.8%, 13.2%, and 60.9% lower after 15 years' reclamation than those in control. The acid phosphatase in 0–10 cm and 10–20 cm was increased by 2.2 and 2.1 times, respectively, after 15 years compared with that after 2 years. Alkaline phosphatase was decreased by 16.8% reclaimed after 15 years than that after 2 years in 10–20 cm soil. The Shannon diversity index of fungi was increased by 42.0% and 43.8%, respectively, in 0–10 cm and 10–20 cm, in the waste dump reclaimed after 15 years than that after 2 years. Soil organic matter was positively correlated with soil urease activity. Soil pH, EC, and texture had different effects on bacterial and fungal communities. Therefore, appropriate measurements should be applied to the reclamation dumps to help the soil properties of reclamation areas to recover to the natural grassland.

Trends of Global Scientific Research on Reclaimed Coal Mine Sites between 2015 and 2020

“…The input query words used before now give a much broader list of publications, most of which are completely off-topic, compared to the very narrow-focused results we obtained in 2020. When modified slightly and still using similar keywords (coal, soil, recla*), some of the most recent publications from 2023 visible in the WoS database related to the matter mainly originate from China [167][168][169][170][171][172][173], India [174][175][176], and Poland [177][178][179][180], with research coming from China definitely being the most abundant.…”

Restoration Strategies in the Heidaigou Open-Pit Mine Dump Based on Water Sources and Plant Water Utilization

“…Accordingly, the ecological restoration of mining areas has become the focus of national and local governments [9]. Determining how to carry out vegetation restoration and reconstruction on the dump formed by the accumulation of waste is of great significance for coordinating the utilization of water and soil resources in the region, restoring soil quality, and promoting the sustainable development of coal mines [7,10]. Soil water is the main source of water absorbed by plants, but the spatial distribution of soil water is not uniform, resulting in different degrees of utilization of soil water by different plants.…”