Ammonium sulphate: Cycles

Why a by-product crashes harder in a glut

What this tab covers How its prices and margins move: past booms and busts with price levels, the spread or margin that the industry watches, the drivers of the cycle and the metrics to track.

AS prices follow urea and the wider nitrogen market but at a discount per unit of N, plus some value for sulphur. Because supply is mostly by-product, it does not fall when prices fall, so AS weakens sharply in gluts and only partly tracks nitrogen spikes. Chinese caprolactam expansion has added a structural surplus since about 2020, absorbed by Brazil, Southeast Asia and, in 2025, Europe ahead of CBAM. Sulphur deficiency in soils is lifting underlying demand (CRU). The floor is near zero for by-product producers; the ceiling is the cost of N plus S from urea and sulphur.

The spread to watch AS price per unit N versus urea per unit N

AS at $277/t (Feb 2026) is about $1,320/t N (0.21 N); urea at $472/t (World Bank, Feb 2026) is about $1,026/t N. The AS premium per unit N reflects its 24% sulphur, worth roughly $70/t of AS at $300/t sulphur (indicative).

Booms and busts

2021-2022
The nitrogen price spike lifted AS with urea; China's export inspections and curbs on fertiliser from late 2021 limited supply.
India's AS import price averaged $309/t in 2022 (IndexBox); World Bank urea peaked at $925/t (Apr 2022)
2023
Nitrogen prices fell and Chinese exports rose, so AS prices halved.
India import price averaged $175/t in 2023, down 43% (IndexBox)
2025
China exported a record of just over 21 Mt; EU buyers rushed 1.53 Mt in before CBAM, a record.
EU December 2025 imports 522 kt, up 316% y/y (S&P Global)
2026
The Hormuz near-closure spiked urea, but ample Chinese AS capped European prices; China halted customs inspections for some fertiliser exports in March (Argus).
caprolactam-grade AS $277/t FOB NW Europe (19 Feb 2026, Platts); World Bank urea $857/t (Apr 2026)

What drives the cycle

Chinese caprolactam output. Sets by-product supply; caprolactam ran at about 80% in 2026 (Argus).
Urea prices. AS competes with urea for nitrogen value.
Brazilian soy and sugarcane demand. Brazil is about 70% of Latin American demand by value (GMI).
Sulphur deficiency and sulphur prices. Makes the S content worth more; sulphur prices spiked in 2025-2026.
EU CBAM and trade policy. Changes import timing and origin into Europe.

Metrics to track

Metric	Why it matters	Where to track it
AS caprolactam-grade FOB NW Europe; standard and granular FOB China; CFR Brazil	main benchmarks	S&P Global Platts, Argus, CRU
China AS exports by month	dominant supply	China General Administration of Customs
Urea FOB Middle East	nitrogen anchor	World Bank Pink Sheet; Argus