Bacterial community structure in reclaimed soil filled with coal wastes in different reclamation years

摘要

Soil microbe is the core component of soil ecosystem and the soil microbial community structure plays a key role in the formation of soil fertility. Therefore, it is important to study soil microbial community structure and monitor the quality level of reclaimed soil, and it has practical guiding significance to improve the soil quality through microbial measures in ecological restoration. In this study, the soil samples (RS) from the reclaimed land filled with coal gangue with different reclamation years in Xuzhou mining area were compared with soil samples (CS) from normal farmland which were not affected by coal mining subsidence. Illumina PE250 sequencing method was used to determine the sequence numbers of six levels of bacteria phylum, class, order, family, genus and species bacterial and analyzed the vertical structure and time structure of bacterial community. (1) Compared with CS samples, the number of bacteria species and the bacterial diversity in RS samples decreased. (2) RS belonged to Firmicutes and Proteobacteria at the phylum level. After the disturbance of the reclamation project, Firmicutes increased and transferred from 20-40 cm to 0-20 cm soil layer. Bacilli had an absolute advantage at the class level. Quantity of Bacilli in the 0-20 cm soil layer was higher in RS than in CS samples, and with the increase of the reclamation years the quantity of Bacilli in 20-40 cm soil layers of RS samples decreased while in 0-20 cm soil layer had no changing trend. RS belonged to Lactobacillales and Bacillales at the order level. Desulfuromonadales played an important role in the remediation of heavy metal pollution and the quantity in 0-20 cm of RS was 74.81% -99.59% less than that in CS samples. (3) In RS samples, Bacillus, Enterococcus and Streptococcaceae were the dominant family, while Bacillus, Enterococcus and Lactococcus were the dominant genus, and Bacillus sp. JH7, Enterococcus faecium and Lactococcus piscium were the dominant species. All of these in RS samples were less in number than CS samples especially in 0-20 cm soil layer. The quantity of these in 20-40 cm soil layer of RS decreased with the increase of the reclamation years.