Material Insights · Understanding the Material World

DAP and MAP and Sulfur

Phosphate fertiliser plants burn sulphur to make the sulphuric acid that dissolves phosphate rock, using about 0.4 tonnes of sulphur per tonne of DAP. Sulphur supply is set by oil and gas processing rather than by fertiliser demand, so sulphur price spikes, such as the rise from under USD 100 to over USD 1,000 a tonne between 2024 and 2026, pass straight into DAP costs.

DAP and MAP (chemical) and Sulfur (commodity): 4 relationships.

How they are linked

1. Acid feedstock

Physical flow · Strong · Sulphur to DAP and MAP

Sulphur is burned to sulphuric acid, which reacts with phosphate rock to make phosphoric acid, the base of DAP and MAP; the sulphur leaves the process mainly in phosphogypsum.

  • about 0.4 t sulphur per tonne of DAP
  • 60 to 75% of US sulphuric acid consumption historically used for phosphate fertiliser

Because each tonne of DAP needs so much acid, phosphate fertiliser is the largest single use of sulphur and sulphuric acid. Plants sited next to smelters or using smelter acid avoid buying elemental sulphur, but most large phosphate complexes burn imported sulphur.

Sources: farmdoc daily, University of Illinois; US EPA

2. Price link: main demand

Cost and price · Strong · Both ways

Phosphate fertiliser demand is the main driver of sulphur and acid demand, so swings in fertiliser markets move both prices together.

  • 0.26 monthly change correlation
  • 0.66 12-month change correlation
  • 0.53 fitted elasticity

The yearly link is strong while the monthly link is moderate, because sulphur and DAP contracts reset at different times and each has its own supply shocks. The proxy used here is the acid price, which tracks sulphur closely.

Sources: Material Insights (World Bank, FRED, IMF data)

3. Sulphur cost in DAP

Cost and price · Rising · Sulphur price to DAP cost and price

With about 0.4 t of sulphur in each tonne of DAP, every USD 100 rise in the sulphur price adds about USD 40 to the cost of a tonne of DAP, which producers try to pass on.

  • under USD 100 to over USD 1,000 sulphur price per ton, 2024 to mid-2026
  • about USD 850 DAP price per short ton, US Corn Belt, autumn 2025 and again in August 2026
  • USD 116 to 310 Tampa sulphur contract price per long ton, start of 2025 to October 2025

Sulphur passed USD 200 a short ton by spring 2025 and USD 400 by the end of 2025, then climbed above USD 1,000 in 2026 amid Middle East supply disruptions linked to the conflict in Iran and export curbs by China and Russia. DAP prices rose far less in percentage terms, so non-integrated producers buying sulphur on the spot market saw their margins squeezed.

Sources: farmdoc daily, University of Illinois; USGS

4. Supply set by oil and gas

Shared risk · Asymmetric · Refinery and gas output to sulphur supply

Most sulphur is recovered as a by-product of oil refining and natural gas processing, so supply depends on hydrocarbon output and shipping from the Gulf, not on fertiliser demand.

  • about 84 Mt world sulphur production, 2025
  • 19 Mt China's sulphur production, the largest, 2025
  • 3.7 Mt India's sulphur production, 2025

When fertiliser demand rises, sulphur supply cannot respond, so prices jump instead. New sulphur demand from phosphate projects is expected mostly in Africa and west Asia, while supply stays tied to refinery runs and gas processing.

Sources: USGS

For investors

Key learnings

  1. Sulphur is a by-product with inelastic supply, so when fertiliser demand rises its price can multiply, as it did from 2024 to 2026.
  2. At about 0.4 t of sulphur per tonne of DAP, sulphur has become a large swing cost for phosphate producers that buy it rather than make it.
  3. Producers with their own sulphur or acid, such as those integrated with refineries, gas plants or smelters, are protected when sulphur spikes.

What to track

  • Sulphur price, Middle East FOB and China CFR: A sharp rise squeezes non-integrated phosphate producers (Weekly · Argus, CRU; quarterly Tampa contract)
  • DAP price minus sulphur, rock and ammonia costs: A shrinking spread signals production cuts at high-cost plants (Monthly · World Bank Pink Sheet and trade press)
  • Shipping through the Strait of Hormuz: Disruption cuts Gulf sulphur exports, the largest traded source (Daily · shipping trackers, news)

For policymakers

Key learnings

  1. India imports much of the sulphur and sulphuric acid its phosphate plants use, so sulphur spikes raise domestic DAP costs and the subsidy bill.
  2. Refinery expansion in India adds sulphur recovery, which can be directed to fertiliser plants to cut import exposure.
  3. Sulphur supply depends on oil and gas output, so a long-term fall in fossil fuel refining would tighten sulphur supply for fertilisers.

What to track

  • Sulphur and sulphuric acid imports: Rising import bills show cost pressure on domestic phosphate plants (Monthly · DGCI&S)
  • Nutrient Based Subsidy rates against input costs: A gap between subsidy and cost discourages domestic DAP production (Each season · Department of Fertilizers)
  • Domestic refinery sulphur output: More domestic sulphur reduces import exposure (Monthly · PPAC, refinery reports)

India

India produced about 3.7 Mt of sulphur in 2025, but its phosphate fertiliser plants also rely on imported sulphur and acid, so sulphur price spikes feed into domestic DAP costs.

Sources

  1. Price correlation, Material Insights, Material Insights (World Bank, FRED, IMF data)
  2. Sulfur and increasing phosphate fertilizer prices, farmdoc daily, University of Illinois (2026)
  3. Mineral Commodity Summaries 2026: Sulfur, USGS (2026)
  4. Sulfuric acid supply chain profile, US EPA (2023)