Review on Mechanisms of Phosphate Solubilization in Rock Phosphate Fertilizer

Phosphorous (P) is an indispensable element for all life forms. Even though P is applied to the soil mostly in fertilizer, it has been found to be inefficient, because only a small portion of the applied P which is supplied is actually utilized by the plant. Therefore, there is a critical need to increase the solubilization of P in order to make it readily available for plants. Various methods of solubilizing P from Rock Phosphate (RP) are discussed in detail in this review article, which includes physical treatments, chemical treatments, and application of microorganisms as well. One of the main methods of P solubilization is the application of organic acids. Since citric acid is a tricarboxylic acid, it can act as a very good chelating agent to chelate with metal cations. Therefore, usage of citric acid to solubilize P from RP and mechanism are briefly discussed in this article. Further, methods for P solubilization such as colorimetric, volumetric, and gravimetric methods have been discussed in brief.