Beneficial Microorganisms for the Sustainable Use of Phosphates in Agriculture

Phosphorus (P) is vital for plant growth. However, most added soluble P forms insoluble phosphates. Therefore, inorganic P (Pi) accumulates in soils. Soil organic P (Po) is another important reserve (20 to 80% of total soil P). To be available for plant Po must first be mineralized by soil microorganisms. The variability of the results of inoculation trials with P solubilizing microorganisms (PSMs) clearly reflects the complexity of the interactions occurring in the soil-plant-microbes-fauna ecosystem. Important points overlooked in previous studies will be presented and perspectives of the use of PSMs to allow the plant to benefit from soil reserves in Pi and Po will be discussed.