Relative Efficiency of Ammonium Polyphosphate as Measured by Wheat Yield, P Uptake and Fractionation Studies

Pot culture and laboratory studies were carried out to compare liquid ammonium polyphosphate (APP), diammonium phosphate and chloride-free NPK-5:52: 21 (NPK) as P sources for wheat on a P deficient sandy loam soil (Ustochrept) of Hisar district. Grain and straw yield of wheat significantly increased with all the three sources of P but DAP and APP were at par whereas chloride free NPK was statisically inferior to the other two sources. Higher amounts of saloid P and Al-P were recovered under DAP and APP, however, Fe-P and Ca-P were more formed under Cl-free NPK. Olsen's available P was maximum under DAP followed by APP and least under Cl-free NPK.