Woody plants have the advantages in the phytoremediation process of manganese ore with the help of microorganisms

Abstract

The serious ecological damage caused by mining activities cannot be ignored. The use of an environmentally friendly restoration method to rebuild the vegetation and soil environment in the mining area has attracted more and more attention. This paper aims to study soil quality as well as vegetation characteristics of four woody species including Pinus massoniana (P. massoniana), Broussonetia papyrifera (B. papyrifera), Koelreuteria paniculata (K. paniculata), Osmanthus fragrans (O. fragrans), and two herbaceous species including Setaria viridis (S. viridis) and Cynodon dactylon (C. dactylon). In addition, we further clarified the effects of B. papyrifera and K. paniculata on soil nutrients and microbial communities after restoration. The results showed that the vegetation restoration area had better soil quality and plant community diversity, and the woody plants restoration effect were better. Compared with slag, B. papyrifera and K. paniculata remediation could improve soil pH and mitigate heavy metal contamination in mining areas, but was not effective in enhancing Soil Organic Matter (SOM), Total Nitrogen (TN), Total Potassium (TK) and Total Phosphorus (TP). In addition, the abundance and diversity of soil bacterial communities were increased. Of all the study sites, Proteobacteria had the greatest dominance. Vegetation restoration resulted in an increase in the relative abundance of Acidobacteria, while a decrease in Actinobacteria, Cyanobacteria and Firmicutes. With the restoration of vegetation, the increase of pH, the change of TN, SOM, TK, TP and the mitigation of Manganese (Mn) pollution were the main reasons affecting the soil microbial community. This study has great significance for understanding the ecological changes in the mining area after artificially mediated vegetation restoration, including changes in soil environment, plant community and microbial community, and woody plants will be more encouraged for the restoration of manganese mining areas.

Keywords: Manganese mining areas; Microbial communities; Plant communities; Vegetation restoration.