Di-Ammonium Phosphate (DAP) Download DAP Product Update . It is a highly unstable compound with the formula (NH 4) 3 PO 4. The NBC presented competitive effects on growths of maize and ryegrass as a commercial fertilizer diammonium phosphate in pot experiments. Experiments conducted to investigate the effects of Ca2+ concentration on P removal from synthetic solutions containing 3.5 mg PO43−-P l−1 in the presence of cow bone showed that the residual P concentration dropped by 10% or more when the Ca2+ concentration was increased from 20 to 50 mg l−1 (Jang and Kang, 2002). Phosphate Fertilizers 4. A related "double salt", (NH4)3PO4 (NH4)2HPO4 is also recognized but is too unstable for practical use. (2009). Key Benefits. For example, nucleation is believed to be initiated by the formation of a metastable precursor, characterized by an amorphous phase consisting of calcium phosphates at a Ca/P molar ratio of between 1 and 1.5 (Zoltek, 1974). Aluminum (as Al, Two processes have been used to produce triple superphosphate: run-of-the-pile (ROP-TSP) and granular (GTSP). Diammonium phosphate is a salt of weak base (3