Editorial Article
Six Times MAP for a Phosphorus the Plant Cannot Use
Phosphite fertiliser sells its phosphorus for six times what monoammonium phosphate gets for the same element. And the plant cannot use it.
That is not a paradox. Phosphorus in the +3 oxidation state cannot enter plant metabolism until it is oxidised to +5. Applied as potassium phosphite, the nutrient is, in the strictly nutritional sense, unavailable. Which means the buyer is not purchasing phosphorus at all. He is purchasing a disease claim, priced against the fungicide it displaces — and once you see that, every number in this market stops looking anomalous.
Six times, on identical element
| What one tonne of P2O5 costs, 2025 | Basis | USD per t P2O5 | vs MAP |
|---|---|---|---|
| Monoammonium phosphate | RMB 3,853.33, 61% P2O5 | 779 | 1.0× |
| Potassium phosphite | RMB 23,000, 59.05% P2O5 equivalent | 4,801 | 6.2× |
| Branded 0-28-26 liquid | USD 16,025.8/t at 28% P2O5 | 57,235 | 73.5× |
MAP rose 23.64 per cent in 2025 — one of only three fertiliser lines that rose at all — and still sells its P2O5 for a sixth of what the phosphite gets. There is no cost argument for the gap: the acid in a tonne of phosphite is the cheapest merchant acid in the phosphate complex. There is no agronomic argument either, as above. What there is, is a crop-protection value proposition that happens to be delivered in a fertiliser jug.
The top row of that table is an asking price from a single reseller and is flagged as one in the parent report. It establishes direction and order of magnitude, not a market level. The 6.2× is the number that matters.
Fifty-two per cent, from a bucket and a stirrer
| Per tonne of KH2PO3, 2025 | Input | RMB | Share of cash cost |
|---|---|---|---|
| Phosphorous acid | 0.683 t at RMB 11,000 | 7,512.9 | 68.1% |
| Potassium hydroxide | 0.466 t at RMB 7,556 | 3,524.1 | 31.9% |
| Cash cost | 11,037.0 | ||
| Price | 23,000 | ||
| Gross spread | 11,963.0 | 52.01% |
Set that against the rest of the segment: phosphorus trichloride at 3.5 per cent, thermal acid around 12, sodium tripolyphosphate at 21.78, feed phosphate at 6.76. The product made by a one-step neutralisation at atmospheric pressure earns eight times the margin of the product made in a submerged-arc furnace.
And it is barely exposed to the element. A tonne carries 0.258 tonnes of phosphorus worth RMB 6,275.6 — 27.3 per cent of price. A 10 per cent move in yellow phosphorus is 2.7 per cent of the product price and 5.2 per cent of the spread, against 2.7 times the entire margin in the chloride market. This product does not hedge phosphorus because it is not selling phosphorus.
What it is exposed to is potash. Potassium hydroxide is electrolysed potassium chloride; KCl closed 2025 at RMB 3,533.33, up 33.33 per cent, and December’s caustic sheets ran RMB 6,000–9,000. For a product where KOH is 31.9 per cent of cash cost, that is the input that actually moves the margin.
The same molecule is a pesticide in Europe and a barred fertiliser
| Date | Instrument | Effect |
|---|---|---|
| 1 Oct 2013 | Reg (EU) 369/2013 | Approved as an active substance, to 30 Sep 2023 |
| 8 Dec 2020 | Reg (EU) 2020/2007 | Extended to 31 Jan 2026 |
| Oct 2022 | Commission proposal to CEG-FP | To permit phosphite biostimulants in fertilising products — not adopted |
| 21 Feb 2024 | EBIC contribution | Industry asks for narrower wording: “inorganic phosphonate salts [phosphites]” in PFC 6 and 7 |
| 17 Nov 2025 | Reg (EU) 2025/2316 | Extended by 42 months → expiry end-July 2029 |
| 1 Jul 2026 | Consolidated 2019/1009 | Annex II still bars phosphonates from any EU fertilising product |
The 42 months is not a decision. The recitals say why: the risk assessment “has not been finalised yet by the rapporteur Member State”. Thirteen years after first approval, the Union has not finished assessing the substance. So it remains an approved pesticide and a prohibited fertiliser in the same territory, during the same period.
The Chinese half of the asymmetry runs the other way. Under the Fertiliser Registration Measures, macronutrient water-soluble fertilisers need only a filing with MARA, and potassium dihydrogen phosphate — the phosphate analogue — is exempt from registration altogether. The barrier to selling this tonne in China is a dossier; the barrier to selling it in France is an authorisation the Commission has been unable to complete since 2013.
That is the mechanism behind the gap between the merchant tonne and the branded tote. One market prices a disease claim inside a lightly-filed fertiliser; the other prices it as a plant protection product that has to clear a regulatory process still in progress.
Where the ladder puts it
On the contained-phosphorus ladder, with the element at 1.00, phosphite sits at 3.67 — above rock (0.32), dicalcium phosphate (0.70), thermal acid (0.88), MCP (0.91), PCl3 (1.05) and the salt (1.32); below only the herbicide at 5.58.
The product with the least usable phosphorus in the chain is priced above every other product in it except glyphosate. That is the sentence this market exists to prove, and it is why the tonnage is small — 145.2 kt, USD 428.4m in 2025, reaching USD 676.0m by 2033 — while the price is not. A market that small, earning a 52 per cent gross margin on a one-step reaction, will attract capacity the moment either regulator moves. That is the thing to watch: not the phosphorus price, and not the disease pressure, but which of the two authorities finishes first.