Effects of different vegetation restoration types on soil bacterial communities and ecosystem functions in mining area

To investigate the characteristics of soil bacterial communities and ecosystem functions of different reclaimed vegetation types in reclaimed mine sites, we selected the surface soils of vegetation areas with no vegetation cover (CK), herbaceous plants (GL), poplar (GPL), and mixed forests (ML) as the research objects in this paper, and analyzed the characteristics of soil bacterial community diversity and composition and potential functions of soil bacterial communities in different vegetation types through high-throughput sequencing of 16S rRNA genes, and fitted a comprehensive fertility index through principal component analysis (PCA) to comprehensively evaluate the quality of soil fertility in various aspects. The results showed that: (1) There were significant differences ( p  < 0.05) in soil physicochemical characteristics among different vegetation types, with ML mixed forests having the highest organic carbon and total nitrogen contents and the lowest electrical conductivity. Soil effective phosphorus and effective potassium were highest in the GL herbaceous area, with significantly higher soil sucrase and urease activities. (2) Soil bacterial community characteristics differed significantly ( p  < 0.05) among vegetation types, with higher soil bacterial community diversity in GL herbaceous plants and lower diversity but highest co-occurrence network complexity in ML mixed forests; (3) KEGG enrichment analysis showed that the abundance of pathways related to carbon, nitrogen and sulphur metabolism were all higher in the soil of GL herbaceous plants, and lowest in GPL poplar; (4) The results of the integrated fertility index fitting showed that the integrated fertility index of soil ponds was highest in the soil of GL herbaceous plants, and lower in the other types of soils. In summary, different vegetation restoration types were able to improve soil quality and soil bacterial community diversity, and the herbaceous-restored surface soil had higher levels of fertility and bacterial community function, providing empirical data for subsequent vegetation restoration in the area.