Soil bacterial community structure in coal mining area and its response to different reclamation patterns

Scientific revelation of soil bacterial community stability and potential interactions between different reclamation models is essential for differentiated management and sustainable use of reclamation land. The diversity of soil bacterial communities under different reclamation modes was studied by analysis of variance and Spearman correlation based on high-throughput Illumina Miseq 16S rRNA sequencing technology. By constructing a molecular ecological network model, the stability of soil bacterial communities and the potential interaction relationships between microbiota under different reclamation modes were revealed, and the microbial populations that play a key role in the stability of bacterial community structure were clarified. The results showed that: ① There were significant differences in the diversity and richness of soil bacterial communities in different reclamation models (P<0.05), which were manifested as deep digging of shallow > gangue filling > fly ash filling. The composition of soil bacterial communities in different reclamation models was similar, Proteobacteria, Acidobacteria Actinomycetes and Bacteroides were the dominant phylum in all model soils, with their combined proportions accounting for over 70% of the soil bacterial communities in each reclamation mode. ②The significant influencing factors on soil bacterial communities varied among different reclamation models, and the change trend between some dominant bacterial phyla and influencing factors was different. Organic matter content was identified as the main influencing factor for deep digging and shallow reclaimed soil bacterial community composition, while pH played a major role in the composition of soil bacterial communities in reclaimed soil filled with gangue and fly ash. ③The soil bacterial networks in the deep digging and shallow reclamation models are complex, with closely connected communities that facilitate the transmission of substances, energy, and information. In contrast, the connectivity between nodes in the bacterial network of gangue filling soil is low, but the exchange of information within the network is slow. It has four key nodes and relatively stable network structure. The soil bacterial network of fly ash filling reclamation is the smallest, with low node connectivity. However, it responds quickly to changes in the external environment, but has the poorest network stability. The relationships between soil bacterial communities in the three reclamation models are characterized by collaborative cooperation, with the highest proportion of synergistic cooperation observed in gangue filling reclamation. This study reveals the differences in soil bacterial community structure and molecular ecological networks under different reclamation modes, providing support for the optimization of land reclamation strategies and the selection of intervention methods in areas with high groundwater levels caused by coal mining subsidence.