Application of Inorganic Phosphorus Fertilizer

Abstract

Phosphorus deficiency has been identified as a major constraint to crop production on highly weathered, low activity clay soils in the humid and subhumid zones of sub-Saha-ran Africa. Phosphorus deficiency is further accentuated on many of the soils, especially Ul-tisols and Oxisols, because of fast reversion of soluble P into insoluble forms through reactions with iron and aluminum oxides. Phosphorus fertilization is of fundamental importance for sustaining crop production, maintaining soil fertility, and enhancing the fertility of degraded soils. Recent research indicates that the application of inorganic P through soluble and relatively reactive phosphate rock (PR) sources can be effective in increasing crop production and productivity, enhancing the replenishment of N through biological fixation, and in the maintenance of improvement of the overall fertility of soils. The effectiveness of PR and the residual value of fertilizer P from soluble and rock P sources can be enhanced by amending them with locally available organic and crop residues or by the recycling of P from rock RP through leguminous crops. It is suggested that an approach in which the use of P-efficient genotypes and P management are integrated is more practical and sustainable.