Abstract:[Background] Phosphorus is one of the essential nutrients for crop growth, and phosphorus deficiency in soil can reduce the yields of crops such as maize. Phosphate-solubilizing bacteria can convert insoluble inorganic or organic phosphorus in the soil into soluble phosphorus, which is easily absorbed by crops. This process helps improve soil quality and subsequently promote crop growth. [Objective] To isolate and identify efficient phosphate-solubilizing bacteria from the black soil in northeast China, enhance soil quality, and promote maize growth, providing elite microbial strains for the development of microbial inoculants suited to the black soil environment in northeast China. [Methods] The culture method was employed to isolate microbial strains, and then the phosphate-solubilizing ability and indole-3-acetic acid secretion ability of the isolates screened out were characterized. The effects of phosphate-solubilizing bacteria on soil quality were studied based on the physicochemical properties of soil. Furthermore, pot experiments were carried out to study the effects of the strains on maize growth. [Results] A total of 16 phosphate-solubilizing bacterial strains were isolated from the black soil in northeast China. Among them, Staphylococcus sp. GL-HT-43 and Enterobacter sp. W-H-13 were applied to the black soil planted with maize, which significantly increased maize plant height, biomass, and chlorophyll content. Additionally, the two strains notably increased the levels of inorganic carbon, organic carbon, organic matter, and total phosphorus in the black soil. These results suggested that GL-HT-43 and W-H-13 had advantages in reducing fertilizer dependency, promoting maize growth, and enhancing the fertility of black soil. [Conclusion] The efficient phosphate-solubilizing bacterial strains GL-HT-43 and W-H-13 promote maize growth and improve the quality of black soil. These strains demonstrate great potential for the development of phosphate-solubilizing microbial inoculants.
