Biosolubilization of Phosphate Rock Using Organic Amendments: An Innovative Approach for Sustainable Maize Production in Aridisols - A Review

Abstract

Phosphate rock is naturally occurring cheaper mean of phosphorus (P) availability but having drawback of poor solubility. Pakistan is a resource poor country. Economy of Pakistan mainly relies upon agriculture. Phosphorus (P) application (like other essential nutrients) is compulsory for getting higher yield. But availability of P is compromised in those soils having high pH and high calcium content. As at higher pH, conversion of P to plant unavailable forms take place. Chemical P fertilizers are needed to be applied at higher rate to fulfill crop demand. Farmers are unable to apply adequate levels of fertilizers due to poor economy and unavailability of fertilizers at the time of crop requirement. Among alternative cheaper sources of P, one is use of phosphate rock (PR). Pakistan is blessed with huge reserves of PR but poor solubility at higher pH makes it unsuitable for application as such. Thus, solubility of PR needs to be enhanced in a sustainable way. This review documented possible modes of PR dissolution for release of P. Possible means of PR dissolution and resultant P release include use of different organic amendments (e.g. farm yard manure, press mud, poultry dropping etc.), phosphorus solublizing bacteria and fungi as well as employment of plant growth promoting rhizobacteria etc