Microbial mechanisms enhancing soil phosphorus bioavailability through vermicompost application for sustainable agriculture

Although the chemical and biochemical pathways of phosphorus (P) mobilization following vermicompost application are relatively well-documented, the microbial processes that drive the release of sparingly-soluble P remain insufficiently explored. Consequently, this study examined key microbial mechanisms that enhance soil-P bioavailability in response to vermicompost application. First, vermicompost-derived microorganisms can mobilize inorganic P by releasing solubilizing compounds such as protons, siderophores, and carboxylates. Second, vermicompost-derived microorganisms mobilize organic P by exuding phosphatases. Resident soil microorganisms can also contribute to these processes when they are stimulated by the changed soil properties following vermicompost application, including pH and the concentrations of mineral nitrogen (N) and organic carbon (C). Additionally, microbial cell lysis can increase dissolved P concentrations in the soil solution, particularly as microbial biomass expands with vermicompost-derived organic matter inputs. Moreover, the study further explored how microbial mineralization of organic P is facilitated by carboxylates and the C:N ratio in vermicompost. Interactions between vermicompost-derived microorganisms and resident soil microbial communities are crucial, as competition or cooperation between them can significantly affect inorganic-P solubilization and organic-P mineralization. The rapid advancement of multi-omics technologies and the development of synthetic microbial community approaches provide opportunities to identify and optimize efficient P-solubilizing microorganisms. Future research should focus on elucidating microbial interactions and long-term effects of vermicompost-derived microorganisms on soil-P cycling, particularly in agricultural systems. This will provide a foundation for developing tailored, highly efficient P-solubilizing microbial inoculants, effectively translating theoretical insights into practical applications for sustainable agriculture.