Microbial-mediated coal gangue reclamation: enhancing alfalfa growth with potassium and phosphorus-solubilizing bacteria

Large accumulations of coal gangue (CG) pose significant environmental challenges, including land occupation, soil degradation, water contamination, and air pollution. Therefore, the ecological and sustainable utilization of CG is urgently needed. This study aimed to isolate microorganisms from various environmental samples that are capable of solubilizing potassium and phosphorus in CG. The bacteria exhibiting the greatest solubilization potential were identified and characterized, and their effects on alfalfa growth were evaluated in pot experiments using soil mixtures of CG and sandy soil. The findings indicated that Bacillus pseudomycoides and Bacillus amyloliquefaciens significantly improved alfalfa germination rates, whereas Citrobacter freundii and Bacillus velezensis were effective in enhancing its growth. These results suggest a promising approach for the clean and sustainable utilization of CG through the application of these microorganisms