Sustainable phosphorus management: Leveraging phosphate solubilizing bacteria for enhanced rice growth

Phosphorus (P) is a crucial limiting nutrient in soils, directly impacting plant growth and yield. Its availability to plants is generally low due to high fixation, poor solubility and slow diffusion rates. Over 80 % of the P applied to soil in agricultural systems becomes fixed as insoluble phosphates, with less than 20 % being utilized by crops. This leads to an accumulation of P in the soil. Continuous farming with fertilization contributes significantly to this P buildup. Research on P budgets shows that the amount of insoluble P in soil far exceeds what crops need, suggesting a significant opportunity to reduce inorganic P fertilization by tapping into these native P reserves. However, the natural solubilization of these reserves is minimal. Improving P solubilization could help unlock this unavailable P for plant use. Phosphate-solubilizing bacteria (PSB) have gained prominence due to their potential to reduce the need for P fertilizers, mitigate environmental pollution and boost agricultural productivity. This review explores the diversity of PSB, the mechanisms they use to solubilize native soil P, their effectiveness in various environmental conditions and their impact on crop productivity and P use efficiency, particularly in rice systems.