DAP is used as fertilizer. When applied as a plant nutrient, it temporarily increases soil pH, but in the long run, the treated soil becomes more acidic than before upon nitrification of ammonium. It is not compatible with alkaline chemicals as the ammonium ion is more likely to convert to ammonia in a high pH environment. The average pH in solution is 7.5-8. Typical formulation is 18-46-0 (18% N, 46% P2O5, 0% K2O).
DAP can be used as a fire retardant. It lowers the combustion temperature of the material, lowers the maximum weight loss rates and results in an increase in residue or coal production. These are important effects in fighting forest fires as they lower the pyrolysis temperature and increase the amount of coal formed. may result in the build-up of available fuel and cause a fire. It is the largest ingredient in some popular commercial fire suppression products.