Monoammonium Phosphate (MAP)
Chemical Formula: NH₄H₂PO₄ Common Grades: 11-52-0 or 12-61-0
Monoammonium Phosphate (MAP) is one of the most widely used high-analysis phosphorus fertilizers in agriculture. It supplies both Nitrogen (N) and Phosphorus (P₂O₅) in a highly water-soluble form and is particularly valued as a starter fertilizer because of its excellent nutrient availability and favourable soil reaction.
MAP is produced by reacting ammonia (NH₃) with phosphoric acid (H₃PO₄) in a controlled process, followed by granulation or crystallization. The resulting product is free-flowing and suitable for direct application or blending.
Technical Specifications
| Parameter | Unit | Agricultural Grade (Typical) | High-Purity / Technical Grade |
|---|---|---|---|
| Total Nitrogen (N) | % | 11–12 | 12 min |
| Available Phosphate (P₂O₅) | % | 48–52 (commonly 52) | 60–61 min |
| Water-Soluble P₂O₅ | % | High (typically > 90% of total) | Very high |
| Moisture | % | ≤ 1.5–2.5 | ≤ 0.2–0.5 |
| Solution pH | — | 4.0–4.5 | 4.0–4.5 |
| Appearance | — | Granular (grey, brown or light-coloured) | White crystalline powder |
| Bulk Density (approx.) | kg/m³ | 950–1,000 | — |
| Particle Size (granular) | — | Predominantly 2–4 mm | Fine powder / crystals |
Typical Physical Properties
- Highly water-soluble (≈ 370 g/L at 20 °C)
- Free-flowing granules with good handling characteristics
- Creates a slightly acidic zone around the dissolving granule
Key Benefits
- High phosphorus content — One of the most concentrated solid sources of available phosphate.
- Excellent starter fertilizer — Provides immediate nitrogen and phosphorus near the seed, promoting strong early root development.
- Acidifying effect — Temporary lowering of pH around the granule improves phosphorus availability, especially useful in neutral to alkaline soils.
- Lower risk of ammonia toxicity — Safer for placement near germinating seeds compared with DAP in many situations.
- High solubility — Rapid nutrient release in moist soil.
- Versatile — Suitable for soil application, bulk blending, fertigation (soluble grades), and limited foliar use.
Recommended Applications
Highly suitable for:
- Cereals: Maize/corn, wheat, rice, barley
- Oilseeds: Soybean, canola, sunflower
- Vegetables and potatoes
- Cotton, sugarcane, and many field crops
- Orchards and horticultural crops (as basal or starter)
Preferred situations:
- Starter fertilizer placement near the seed
- Neutral to alkaline soils where phosphorus availability needs improvement
- Blending into NPK compounds
Application Methods:
- Banded or drilled near the seed (starter)
- Broadcast and incorporated
- Bulk blending with other fertilizers
- Fertigation with water-soluble grades
Rates should always be based on soil tests, crop requirements, and placement method.
Packaging Options
- 25 kg or 50 kg polyethylene-lined polypropylene bags
- 500–1,000 kg jumbo bags (FIBC)
- Bulk (loose) for large-scale industrial and agricultural use
Storage & Handling Recommendations
- Store in a cool, dry, well-ventilated warehouse protected from moisture.
- Keep bags sealed and stacked on pallets to prevent caking.
- Avoid prolonged exposure to high humidity.
- Use standard personal protective equipment during handling.
Summary
Monoammonium Phosphate (MAP) is a highly effective, concentrated source of nitrogen and phosphorus. Its high solubility, acidifying reaction, and suitability as a starter fertilizer make it a preferred choice for a wide range of crops and soil conditions, particularly where strong early root development and phosphorus efficiency are priorities.
For commercial inquiries, current availability, soluble grades, or technical data sheets, please contact us.
