Long-term stacking coal promoted soil bacterial richness associated with increased soil organic matter in coal yards of power plants

Purpose Coal exploitation inevitably brings a chain of ecological problems, e.g., land destruction and biodiversity decrease. Most previous studies have investigated the ecological effect of coal mining process and the ecological restoration after coal mining practice. However, no study has concerned about the potential influence of long-term stacking coal process on soil microbial communities, the pivotal components to maintain the health of terrestrial ecosystems. This study aims to investigate the influence of long-term stacking coal on soil microbial communities, as well as the time effect. Materials and methods We collected soil samples from coal yards of four power plants (representing four stacking time: 10, 28, 31, and 71 years) in Huainan city. Soils in the lawn near each coal yard were also selected as control at four sites. Soil microbial communities were analyzed via 16S and 18S rRNA gene sequencing. Results and discussion Our results showed that long-term stacking coal significantly (P < 0.05) increased soil organic matter (SOM), and thus facilitated soil bacterial richness and the shifts of bacterial community composition. We also detected significant (P < 0.05) increase of SOM, bacterial richness, and community dissimilarity with stacking time, indicating a substantial time effect. Meanwhile, predicted functional data implied that stacking coal activated anaerobic microbial communities by forming an anaerobic environment in soils. Conclusions Together, these data provide basic knowledge of the potential influence of long-term stacking coal on soil microbial communities and reinforce the role of SOM in shaping bacterial community composition and richness.