Clogged drippers and alkaline water are two of the biggest headaches in drip irrigation. Green phosphoric acid tackles both while feeding the crop. It delivers phosphorus straight to the root zone in a fully soluble liquid form and lowers the pH of irrigation water, helping keep drippers and lines free of mineral deposits.
Key takeaways
- Green phosphoric acid supplies soluble phosphorus through drip irrigation.
- Its low pH helps acidify hard, alkaline water and dissolve carbonate deposits.
- Typical specification: 40–45% H₃PO₄, with natural magnesium and iron content.
- It is corrosive: handle with protective equipment and ship as declared dangerous goods.
What is green phosphoric acid?
Phosphoric acid (H₃PO₄) is a liquid source of phosphorus widely used in fertigation. Fertilizer-grade green phosphoric acid is named for its apple-green colour, which comes from naturally occurring magnesium and iron. These elements provide a small bonus of secondary nutrition, while the product remains 100% soluble for drip use.
| Parameter | Typical specification |
|---|---|
| Purity as H₃PO₄ | 40–45% |
| Density | 1250–1300 g/L |
| Magnesium (Mg) | 0.7–1.5% |
| Iron (Fe) | 0.3–1.0% |
| Calcium (Ca) | ≤ 0.1% |
| pH | 0–2 |
| Solubility | 100% |
Benefits in drip irrigation
- Direct phosphorus feeding — phosphorus is placed in the root zone, where it is most needed, rather than being fixed in alkaline soils.
- Water acidification — many wells in the Gulf, North Africa and South Asia have high pH and bicarbonates. Lowering pH improves the availability of phosphorus, iron, zinc and manganese.
- Cleaner drippers — acidified water helps dissolve and prevent calcium carbonate scale, extending the life of drip systems.
- Easy dosing — as a liquid, it is simple to inject and measure.
How to use it safely and effectively
- Measure water pH first and dose to reach the target pH recommended by your agronomist, typically slightly acidic for most crops.
- Inject separately from calcium — phosphate and calcium in concentrated form produce insoluble deposits. Keep calcium liquids in a different stock tank.
- Always add acid to water, never water to acid.
- Wear protective equipment — gloves, goggles and protective clothing — and use acid-resistant pumps and fittings.
- Flush lines with clean water after each cycle.
Where it fits
Green phosphoric acid is well suited to drip-irrigated orchards, vineyards, vegetables, plantation crops such as banana, and greenhouse production. It complements solid phosphorus sources such as MAP 12-61-0 and NPK 13-40-13 in a full fertigation programme.
Packing and shipping
Because phosphoric acid is corrosive, it is packed in acid-resistant HDPE containers and shipped as declared dangerous goods, with a Safety Data Sheet (SDS) and the required labelling. Mitra Eco Exports handles this documentation for you, together with the batch Certificate of Analysis, Certificate of Origin and commercial paperwork. Freight for dangerous goods is quoted separately, so share your destination port when you enquire.
Need a quotation?
Tell us the product, quantity and destination port. Our export desk replies within 24 hours with pricing, specifications and sample availability.
Frequently asked questions
Why is it called green phosphoric acid?
Its apple-green colour comes from naturally occurring magnesium and iron in fertilizer-grade phosphoric acid.
Can phosphoric acid clean drip irrigation lines?
Yes. Lowering water pH helps dissolve and prevent carbonate scale in drippers and lines. Follow your system supplier's guidance on concentration.
Can I mix phosphoric acid with calcium nitrate?
Not in the same concentrated stock tank, as insoluble calcium phosphate will form. Use separate tanks.
Is phosphoric acid hazardous to ship?
It is corrosive, so it ships as declared dangerous goods with an SDS and proper packaging. We manage this documentation.
This guide is for general information. Application rates and product choice depend on crop, soil, water quality and local regulations; please consult a qualified agronomist and check registration requirements in your country.