Diammonium phosphate

Diammonium phosphate (DAP) is one of a series of water-soluble salts which can be produced when ammonia reacts with phosphoric acid. DAP is used as a fertilizer and a fire retardant. When applied as plant food, it temporarily increases the soil pH, but over a long term the treated ground becomes more acidic than before. It is incompatible with alkaline chemicals because its ammonium ion is more likely to convert to ammonia in a high-pH environment.

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Diammonium phosphate