Differential analysis of inter-root microbial functional groups of major dominant plants in open pit coal mine drainage sites

The study of the soil environment of the waste dump is of great significance for environmental management and ecological restoration. At present, there is a gap in the knowledge of the influence of the soil microbial community and the corresponding ecological effect of the waste dump in Shengli Coalfield. To investigate the changes in the rhizosphere soil microbial community of the dominant plants after many years of biogeochemical restoration measures, the improvement effects of different bacterial combinations on the dominant plants in the dump were studied, and the bacterial combinations applied to the West No. 2 open-pit coal mine of Shengli Coalfield were screened. Therefore, in the first stage of this study, based on high-throughput sequencing, five dominant plant rhizosphere soils were selected to analyze the characteristics of microbial communities and predict the functions of microbial communities, taking the slope of the dump that has been restored for 15 years as the sample site. The dominant plants were selected as Astragalus adsurgens, Caragana korshinskii, Medicago sativa, Elymus dahuricus, and Brassica campes. In the second stage, through pot experiment, the dominant plants of the first stage were planted, the basic physical and chemical properties of soil and plant physiological indexes of each plant group under different microbial combinations were analyzed, and the different microbial combinations were comprehensively evaluated to screen out the best scheme of microbial combinations.The results showed that: (1) After 15 years of restoration, the soil environment was significantly improved under the biologic blanket covering measures, the soil nitrogen content was still insufficient, and the microbial community diversity was significantly increased, but the overall community structure was still similar to that of the control measures, and the slope of the dump needed longer restoration time. (2) Leguminous plants have the best improvement effect and can better adapt to the soil environment of the waste site. (3) Ascomycetes and basidiomycetes dominate the fungal community, while actinomycetes, Proteobacteria, Chloromycetes, and Firmicutes dominate the bacterial community. Specific strains adapted to the environment were found in all plant groups. (4) Different microbial communities have different development strategies, which are more conducive to adapting to the environment of the dump. (5) Different microbial agents can improve soil nutrients to different degrees, which can effectively improve the absorption capacity of plant rhizosphere for soil nutrients, and improve plant stress resistance and adaptability. (6) Among different microbial agent combinations, TH treatment and TH+BS treatment have better effects and are selected as the best scheme suitable for the Shengli coal field dump. (7) After the application of bacterioides, the diversity of microorganisms increased significantly, and the bacterial communities were mainly Proteobacteria, Bacteroidetes, Gemmatimonadota, and Acidobacteria. The fungal community is mainly Ascomycetes. In different plant groups, the abundance of bacteria and fungi in the treatment of inoculants increased to different degrees compared with the control treatment.