[Characteristics and Assembly Process of Reclaimed Soil Microbial Communities in Eastern Plain Mining Areas]

Understanding how soil microorganisms respond to land reclamation is essential to evaluating the success of ecological restoration actions in disturbed mine soil. However, the microbiological mechanism referred to as productivity reconstruction of the reclaimed soil is still unclear. To shed light on this mechanism, a total of 75 soil samples were collected for 16S rRNA amplicon high-throughput sequencing. The five sampling sites contained four reclamation plots (reclaimed 8 a, 11 a, 14 a, and 17 a) and 1 non-reclaimed plot, which served as the control sampling site. The microbial community composition, potential functions, and assembly mechanisms were also analyzed. The results showed that:①the richness of the microbial community increased with the reclamation time and was higher than that of the control site. However, the community diversity and evenness decreased with the increasing reclamation year (P<0.05). ②Acidobacteria, Chloroflexi, Proteobacteria, and Bacteroidetes dominated in the reclaimed soil, and the relative abundances of the first two phyla were significantly higher than that of the control (P<0.05), whereas the latter two presented the opposite trends (P<0.05). ③ Eight functions, including coenzyme transport and metabolism, translation, ribosomal structure, and biogenesis, showed a positive succession in the reclamation sites and enhanced with increasing reclamation years. ④ The molecular ecological networks of the microbial community in the plain mining area were well modular, whereas the key microbial groups belonged to the Acidobacteria and Bacteroidetes. The microbial communities were dominantly assembled with the deterministic process, and the homogeneous selection contributed the most, which might have been mainly controlled by the local special environment. The results presented herein will undoubtedly aid in the establishment of success indicators of ecological restoration activities in disturbed mining soil. These findings also provide the theoretical basis for improving the productivity and ecological services of reclaimed soil.