Ammonium phosphate fertilizers first became available in the 1960s, and DAP rapidly became the most popular in this class of products. It’s formulated in a controlled reaction of phosphoric acid with ammonia, where the hot slurry is then cooled, granulated and sieved. DAP handles and stores well. The standard nutrient grade of DAP is relatively high, at 18-46-0, so fertilizer products with lower nutrient content may not be labeled DAP.

DAP also acts as a fire retardant. For example, a mixture of DAP and other ingredients can be spread in advance of a fire to prevent a forest from burning. It then becomes a nutrient source after the danger of fire has passed. DAP is used in various industrial processes, too, such as metal finishing. And, it’s commonly added to wine to sustain yeast fermentation and to milk to produce cheese cultures.