Mobility, Availability and Reaction Products of MAP, DAP, and APP Fertilizers In Acid and Calcareous Soils.

Phosphorus management has been a great concern for farmers these days. Millions of tonnes of P fertilizer are applied to agricultural soils each year and a high proportion of this applied P is rapidly converted to insoluble phosphates that plants have virtually no access. Various researches have been conducted for increasing efficiency of applied phosphorus in soil. Therefore, knowledge of the dominant solid P species present in soil following application of P fertilizers and linking that to potential P availability would help us to efficiently manage P in soils systems. X-ray absorption near edge structure (XANES) spectroscopy is an advanced, nondestructive chemical speciation technique that can be used for characterization of chemical species of P in soils.  This study aims to study fertilizer reaction products in soil. The fertilizer sources include monoammonium phosphate (MAP), diammonium phosphate (DAP) and ammonium polyphosphate (APP). The objective of this research is (i) to understand mobility and reaction products of various P sources (ii) to understand the influence of different P sources on P fractionation and available P (iii) to integrate spectroscopy with wet chemical analysis on P fertilizer use efficiency in two different acidic and calcareous soils.