Analysis of Community Diversity of Potential Potassium-Solubilizing Bacteria in Granite Weathering Soil Areas

To reveal the community structure and functional potential of potential potassium-solubilizing bacterial communities in granite weathering soil areas, this study selected two granite-rich regions, Luanchuan in Henan Province and Chicheng in Hebei Province, as the research subjects, with forestry land in Tianjin as the control. Using high-throughput sequencing, we systematically analyzed the composition, diversity, and phenotypic functional predictions of bacterial communities in different soil samples and explored the ecological distribution characteristics of potential potassium-solubilizing bacterial communities. The results showed that in granite-weathered soils, Acidobacteria accounted for 24 %, whereas their relative abundance decreased significantly to only 2 % in the control group. The alpha diversity indices of the granite weathering soil areas were generally higher than those of the control group, indicating a richer and more evenly distributed community of potential potassium-solubilizing bacteria. Non-metric multidimensional scaling (NMDS) based on Bray-Curtis distance yielded a stress value of less than 0.05, indicating a good model fit, with overall greater inter-group differences than intra-group differences, suggesting substantial grouping dissimilarity. BugBase phenotypic functional predictions revealed that in the granite weathering soil areas, potential potassium-solubilizing bacterial communities with biofilm-forming capacity, anaerobic tolerance, and Gram-positive phenotypes were more dominant. In contrast, the potential potassium-solubilizing bacterial communities in the control group soils exhibited higher proportions of phenotypes such as Gram-negative, mobile genetic element-containing, potentially pathogenic, and stress-tolerant.