Effects of Different Vegetation Types on Soil Microbial Functional Genes and Enzyme Activities in Reclaimed Coal Mine

Abstract

Long-term coal mining has seriously damaged soil structures and ecological environments. Reclaimed vegetation could effectively improve the ecological environment. There have been many studies on soil physical-chemical characteristics and microbial community structure, but there are few on soil functional microorganisms in mining areas. In this study, soil physical and chemical properties, soil enzyme activities, and the abundance of functional genes in carbon, nitrogen, phosphorus, and sulfur cycling were determined in five reclaimed lands of different vegetation types (Platycladus orientalis, Picea asperata, Pinus tabuliformis, Pinus sylvestris, and Sabina chinensis) in the Jinhuagong mining area, Datong City, Shanxi province. The results showed that the restoration types produced significant effects on soil physical and chemical properties, soil enzyme activities, and the abundance of 75 functional genes. The highest contents of total carbon, total nitrogen, and total sulfur were in the S. chinensis site. The activities of dehydrogenase and urease were the highest in P. asperata, and the lowest alkaline protease activity was in P. asperata. The alkaline protease activity was the highest in P. sylvestrist. The abundance of functional genes in the P. asperata forest was the highest, but the diversity index was significantly lower than that in other plots, which might be due to the fact that the total abundance of ureC, acsA, and mct in P. asperata accounted for more than 52%. Soil urease was significantly correlated with the abundance of six functional genes. The β diversity of the functional microbial community was significantly different among the different vegetation types, indicating that functional genes could better explain the effects of vegetation types on microbial function. The highest and lowest integrated fertility indexes were found in the P. sylvestris and P. orientalis plots, respectively. In conclusion, soil functional genes are sensitive indicators signifying the effects of different reclamation types on soil microorganisms, and P. asperata and P. sylvestris are more suitable for reclamation in this mining area.