Ammonium Phosphate (MAP / DAP)磷酸铵（磷酸一铵／二铵）
Ammonium phosphate is the collective term for monoammonium phosphate (MAP) and diammonium phosphate (DAP). Both are high-analysis water-soluble phosphate fertilizers and the principal phosphorus sources used in compound and water-soluble fertilizers. Both are made by reacting ammonia with phosphoric acid; the difference lies in the degree of ammoniation and therefore in the nutrient ratio.
Key points
- Typical grades expressed as N-P₂O₅-K₂O: MAP around 12-61-0, DAP around 18-46-0.
- DAP is weakly alkaline and better suited to acid soils; MAP is weakly acidic and better suited to alkaline soils — the choice should follow soil pH, not price alone.
- Both have a high proportion of water-soluble phosphorus and are common phosphorus sources in fertigation systems.
- Fluoride-bearing off-gas and phosphogypsum management are the principal environmental issues in ammonium phosphate production.
Related terms
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- Category：Straight fertilizers
- Definition basis：GB/T 10205-2011 Monoammonium phosphate and diammonium phosphate
Updated：Oct 19, 2026