TSP (triple superphosphate) and SSP (single superphosphate) are phosphate fertilizers that supply phosphorus without nitrogen. TSP is concentrated, at about 46% P2O5. SSP is weaker, at about 16 to 20% P2O5, but it also carries sulphur and calcium. Both are made by treating phosphate rock with acid.
TSP and SSP at a glance
| TSP | SSP | |
|---|---|---|
| Full name | Triple superphosphate | Single (or normal) superphosphate |
| Phosphate (P2O5) | About 46% | About 16 to 20% |
| Sulphur (S) | Very little | About 11 to 12% |
| Calcium (Ca) | About 15% | About 18 to 20% |
| Nitrogen | None | None |
| Made with | Phosphate rock and phosphoric acid | Phosphate rock and sulphuric acid |
| Main form | Granular | Powder or granular |
How superphosphates are made
SSP was the first commercial mineral fertilizer, developed in the 19th century. Ground phosphate rock is mixed with sulphuric acid. The reaction turns insoluble rock phosphate into monocalcium phosphate, which plants can use, and leaves calcium sulphate (gypsum) in the product. That gypsum is why SSP contains sulphur and calcium, and why its phosphate content is lower.
TSP uses phosphoric acid instead. Because phosphoric acid brings extra phosphorus and there is no gypsum diluting the product, TSP ends up roughly two and a half times as concentrated as SSP.
Which one to choose
Choose TSP when
- You need phosphorus but not nitrogen, for example on legumes or where nitrogen is applied separately.
- Freight and handling cost matter: you move far fewer tonnes per unit of phosphorus.
- You blend your own NPK and want a phosphate source that adds no nitrogen.
Choose SSP when
- The soil is short of sulphur, or the crop needs a lot of it: oilseeds, legumes such as groundnut and soybean, and pastures.
- Calcium supply is useful.
- Local production makes it cheap, which is the case in several countries, including India, Brazil and Australia.
TSP and SSP vs DAP and MAP
DAP (18-46-0) and MAP (11-52-0) also supply concentrated phosphorus, but they add nitrogen as ammonium. The choice depends on whether that nitrogen is useful, and on the soil:
- DAP releases some free ammonia as it dissolves, which can harm germinating seed if placed too close. It is the world’s most traded phosphate fertilizer.
- MAP is less likely to release free ammonia and suits more alkaline soils.
- TSP contains no nitrogen, so it suits legumes and blends where nitrogen is supplied separately.
- SSP brings sulphur and calcium as well as phosphorus.
See our guides to DAP fertilizer and MAP fertilizer.
How to apply superphosphates
Phosphorus moves very little in the soil, so placement matters. Superphosphates are usually applied at or before planting, either banded near the seed row or broadcast and worked in. Base the rate on a soil test and the crop’s removal. Because the phosphate in superphosphate is water-soluble, it is available quickly, but on strongly acid or alkaline soils some becomes fixed over time.
Trading and specifications
When you ask for an offer, specify:
- Product: TSP or SSP, and powder or granular.
- Total and water-soluble P2O5: both matter, as they show how much phosphate is available to plants.
- Sulphur and calcium for SSP.
- Moisture, free acid and particle size.
- Packaging: bulk, jumbo bags or 50 kg bags.
- Quantity, destination port and Incoterm.
Our guide to requesting a bulk commodity quotation explains how to set out an enquiry. For phosphate producers and trade data, see the DAP and MAP suppliers database.
Sourcing through Agromer
Agromer has traded agricultural commodities internationally since 1985 from Saint-Avertin, France. Our main fertilizer range is urea, NPK, DAP and potash, with organic products. TSP and SSP are not standard lines, but you can send an enquiry with your specification and we will tell you plainly whether we can help.
Frequently asked questions
What is TSP fertilizer?
Triple superphosphate, a phosphate fertilizer with about 46% P2O5 and no nitrogen. It is made by treating phosphate rock with phosphoric acid.
What is the difference between TSP and SSP?
TSP has about 46% P2O5. SSP has about 16 to 20% P2O5 but also contains sulphur and calcium, because it is made with sulphuric acid.
Is TSP better than DAP?
Neither is better in every case. DAP adds nitrogen as well as phosphorus. TSP adds only phosphorus and calcium, which suits legumes and blends where nitrogen is supplied separately.
Which crops benefit from SSP?
Crops that need sulphur as well as phosphorus, such as oilseeds, groundnut, soybean and pastures.
What does 0-46-0 mean?
It is the grade of TSP: no nitrogen, about 46% phosphate as P2O5 and no potash.
Is superphosphate water-soluble?
Most of the phosphate in TSP and SSP is water-soluble monocalcium phosphate, so it is available to plants quickly.