Ecological Restoration and the Dominant Effects of Rhizosphere Microbes in Carbon Cycling in Mine Areas

Rhizosphere microbes have a significant impact on carbon cycling and other biogeochemical processes, but the relationship between rhizosphere microbial communities and carbon cycling functions in different restoration modes in mining areas remains unclear. This study selected two restoration modes, natural recovery and artificial restoration, and used metagenomic methods to investigate the differences in rhizosphere soil microbial communities and carbon cycling-related functional genes. The results showed that: (1) The artificial restoration mode significantly reduced soil conductivity and salinity. The total phosphorus and available phosphorus content were 12.33% and 16.44% higher, respectively, than in the natural recovery mode. At the phylum level of rhizosphere soil microbial taxonomy, the proportion of specific microbes in the artificial restoration mode was twice that of the natural recovery mode, and the microbial community Simpson index was significantly higher in the artificial restoration mode compared to the natural recovery mode (p<0.05). (2) In the rhizosphere soil of the artificial restoration mode, the relative abundance of carbon decomposition genes related to Aromatic, Lignin, and Starch, as well as carbon fixation pathways, was higher than in the natural recovery mode. (3) In the study of microbial contributions to carbon cycling genes, significant differences in the abundance of key microbes, including Actinomycetia, Chloroflexi, Solirubrobacterales, and Thermomicrobiales, in the artificial restoration mode dominated the carbon cycling functions (p<0.05), enhancing the restoration effect of carbon cycling in the rhizosphere soil of mining areas. This not only provides a better solution for ecological restoration in mining areas but also lays a scientific foundation for the sustainable development of mining areas.