Carbon sequestration microorganisms in mining area
Carbon-fixing bacteria is a potential and important factor, which improve soil fertility. However, the impact and function of rotation and fertilization on carbon-fixing bacteria community in coal-mining subsidence areas remains poorly understood. To narrow this knowledge gap, the composition and abundance of carbon-fixing bacteria were investigated using enzyme-linked immunosorbent assay (ELISA), high-throughput sequencing and quantitative PCR of the cbbL gene [that encodes ribulose-1,5-biphosphate carboxylase/oxygenase (RubisCO)] in coal-mining subsidence soil. In this study, maize monoculture (M) and maize-soybean rotation (R) cropping systems were set up, and four fertilization treatments in each cropping system, namely, CK (without fertilization), inorganic fertilizer treatment (F), organic fertilizer treatment (O), and combined organic and inorganic fertilizer treatment (OF) in a typical coal mining subsidence area. The results showed that the dominant taxa (Proteobacteria, Actinobacteria and Devosia) were significantly changed after fertilization and rotation (P < 0.05). Morever, both monoculture and rotation, soil organic carbon (SOC) and carbon-fixing bacterial biomass were significantly higher in fertilization treatments (F, O and OF) than CK (P < 0.05), but O significantly reduced RubisCO activity (P < 0.05). Carbon-fixing bacterial community structure was strongly influenced by pH, soil organic carbon, alkaline nitrogen and catalase. Our study implies that rotation and fertilization could significantly influence carbon-fixing bacterial community structure and promote soil carbon accumulation, and the fertilization treatments with manure (O) were more conducive, which indicated that carbon-fixing bacteria were greatly conducive to improve soil fertility in reclaimed mining areas and achieve carbon neutrality.