Modification of soil phosphorus pools and soil bacterial community by the application of phosphate-solubilizing bacteria-loaded biochar in saline soils

Saline soils pose challenges for phosphorus (P) availability and plant growth. Biochar and phosphate-solubilizing bacteria (PSB) have been used as soil amendments, but their combined effect in saline soils and their influence on the soil bacterial community remain understudied. This study investigated the potential of PSB-loaded biochar to improve P availability and enhance plant growth in saline soil conditions. Results showed that PSB-loaded biochar treatment significantly increased P availability and plant biomass compared to individual treatments. Analysis of the microbial community revealed notable shifts in bacterial composition, with Firmicutes exhibiting a strong positive correlation with labile P fractions, soil PSB abundance, and alkaline phosphatase activity. Some other native soil bacteria, such as Brevundimonas and Parapedobacter, were also enriched in the PSB-loaded biochar treatment group and positively correlated with soil P availability. These findings highlight the potential of PSB-loaded biochar to improve P availability and shape the soil microbial community in saline soils. The utilization of the biochar-immobilized microbial strains offers a promising approach for sustainable agricultural practices in saline environments.