Effects of different ecological restoration methods on the soil bacterial community structure of a light rare earth tailings pond

Background and Aims The characteristics of microbial communities can directly reflect the physicochemical properties of soil which is important for successful ecological restoration in the tailings pond. Methods The effects of aggregate spray seeding (S1), external-soil spray seeding restoration (S2), and naturally restored dam slope area (S3) on the structure and predicted function of soil bacterial communities and their correlation with environmental factors were analyzed. Results Our study proved that different bacterial communities were formed based on the different ecological restoration methods, and soil water content (W), conductivity (EC), porosity (SP), soil bulk density (BD), organic matter (SOM), available potassium (AK), heavy metals, biomass and diversity of vegetation were the main factors influencing bacterial community composition. In S1, Bacillaceae and Rhizobiaceae were the dominant bacteria, thus the functional abundance involved in the nitrogen cycle was higher than the others. In addition, the dominant bacteria of S1 and S2, Bacillaceae, Rhizobiaceae, and Vicinamibacteraceae, were significantly positively correlated with W, EC, SP, SOM, AK, biomass and diversity of vegetation, while negatively correlated with BD and heavy metals content. The dominant bacterial families of S3, Geodermatophilaceae and Rhodobacteraceae, were significantly positively correlated with BD and soil heavy metal content. Conclusion Different ecological restoration methods result in significant differences in soil bacterial community structure and predicted function. Aggregate spray seeding provided a double inoculation effect of Bacillaceae and Rhizobiaceae for ecological restoration of tailings pond.