The Proposed Mechanism Underlying the Synergistic Effects of Bacillus velezensis and Coal Gangue (CG) on Wheat Growth

Abstract

The synergistic application of coal gangue (CG) and microorganisms has the potential to promote plant growth, yet the underlying mechanisms remain inadequately understood. This study examined the effects of co-applying Bacillus velezensis and CG on wheat growth through pot experiments. The growth parameters of wheat, the physicochemical properties of the soil, enzyme activity, and the microbial community composition were assessed. The combined treatment led to a significant enhancement in wheat growth, with plant height and root length increasing by 32.1% and 35.4%, respectively. Soil nutrient status was markedly improved, with increases in total nitrogen, total phosphorus, total potassium, organic matter, and humic acid. Key soil enzyme activities were also elevated. Microbial community analysis revealed an increase in soil microbial richness and significant enhancements in the generation of phytohormone IAA and ACC deaminase, which were 1.59 and 1.89 times higher than in the control respectively. In conclusion, the combined application of B. velezensis and CG promoted wheat growth by synergistically improving soil fertility, enhancing enzyme activities, and enriching beneficial microbial communities. This study provides a theoretical foundation and a practical strategy for the agricultural utilization of coal gangue and the remediation of infertile soils.