 DAP is the most widely used phosphate fertilizer. It has an analysis of 18-46-0. For most soils with pH less than 7.5, the agronomic effects of diammonium and monoammonium phosphates are equal. Some research has shown MAP to be more effective on calcareous soils where pH exceeds 7.5. DAP has a high ammonium content and can cause germination injury if used in direct contact with seed.
DAP is manufactured by reacting phosphoric acid and ammonia. It contains two ammonia molecules. In alkaline soil conditions, one of the ammonia molecules in DAP will revert to ammonia. DAP is alkaline with a high pH. |
