Nitrogen Use Efficiency, Nitrogen Fertilizers, NUE, Nitrogen and the EnvironmentAmmonium Phosphates 
Nitrogen Use Efficiency
 

Nutrient Content, %
Source N P2O5 K2O CaO MgO S Cl Form Cost/lb N
Monoammonium phosphate (MAP) 11 48-55   2 0.5 1-3   solid  
Diammonium phosphate (DAP) 18-21 46-54           solid  


From Havlin, Beaton, Tisdale and Nelson (1999)

Ammonium Phosphates
Monoammonium (NH4H2PO4) and diammonium (NH4)2HP04 phosphates are considered to be more important as sources of P than N.