Effects of lignite dust on organic carbon mineralization and bacterial community in reclaimed soil in mining area

After coal dust sinks to the surface, it can significantly increase the content of soil organic carbon and change the soil physicochemical properties and soil microbial community structure. This article explored the mechanism of the effect of organic carbon input from coal dust on soil organic carbon mineralization and bacterial community structure through soil cultivation experiments with the addition of lignite dust. The results showed that under the influence of lignite dust, the amount and rate of CO₂ mineralization in soil increased by 55.02% and 54.58% compared to the control group on day 5; the contents of readily oxidation carbon (ROC) and microbial biomass carbon (MBC) in soil decreased by 40.75 and 141.39 mg/kg, respectively, compared to the maximum values after the end of cultivation. The addition of lignite led to a significant decrease in the relative abundance of Proteobacteria, while the relative abundance of Acidobacteria, Actinobacteria, and Firmicutes increased. The organic components input from lignite dust can produce stimulating effects in the short term. Its decomposition process by soil bacteria can also promote the accumulation of soil CO₂ mineralization, increasing the diversity and variation of soil bacterial communities. The organic carbon in lignite dust greatly participates in the turnover process of soil organic carbon pool.