Diammonium phosphate (DAP) is the world’s most widely used phosphorus fertilizer. It’s made from two common constituents in the fertilizer industry, and its relatively high nutrient content and excellent physical properties make it a popular choice in farming and other industries. DAP (NH4)2HPO4: Fertilizer grade DAP Contains 18% Nitrogen and 46% Phosphorus (P2O5).. DAP is manufactured by reacting Ammonia with Phosphoric acid under controlled conditions in fertilizer plants. Packaging: In bulk or bags / 25KG / 50 KG