Effects of functional microbial agents on the microbial community and fertility of reclaimed soil in a coal mining area

Low soil fertility is the main factor limiting ecological restoration in coal mining reclamation areas. To improve the nutrient status and microbial community structure of reclaimed soil in coal mining areas, we tested a management strategy combining functional microbial agents, NPK, organic fertilizer, and straw to amend reclaimed soil. We selected corn as the crop for our greenhouse pot experiment, with a cultivation period of 80 days. Greenhouse pot trials were conducted with six treatments: no microbial agent (NMA), including CK (NPK), M (organic fertilizer and NPK), and S (straw and NPK); microbial agent (MA), including B (microbial and NPK), BM (microbial agent, organic fertilizer and NPK fertilizer), and BS (microbial agent, straw and NPK fertilizer). The results showed that the adding microbial agents changed the community structure of bacteria and fungi, and significantly changed the indicator microbial composition. The MA treatment group had an increase in five bacterial microbial network modules related to C and N functionalities such as Proteobacteria and Nitrospirae. In comparison to the B treatment, the combination of microbial agents with organic materials (BM and BS) significantly enhanced soil nutrient contents, including soil organic carbon (SOC), total nitrogen (TN). Therefore, the addition of functional microbial agents (Sphingomonas leidyi, Paenibacillus amylolyticus, and Paenibacillus mucilaginosus), especially in combination with organic materials, can significantly improve the contents of carbon, nitrogen and phosphorus nutrients, bacterial functional activity, and beneficial bacterial abundance in reclaimed soil, which is essential for the rapid improvement of reclaimed soil fertility in coal mining areas.