While nitrogen price increases have captured widespread attention, phosphate fertilizers have staged a quiet, multi-year climb that is now accelerating into major expense increases for producers. University of Illinois agricultural economist Nick Paulson noted that rising sulfur prices and global supply chain disruptions have become the primary driving forces behind surging phosphate costs.
Sulfur’s Role in Phosphate Production
Addressing market dynamics with University of Illinois Extension’s Todd Gleason, Paulson explained the core economics behind common phosphate fertilizers like DAP (diammonium phosphate) and MAP (monoammonium phosphate). While anhydrous ammonia production depends heavily on natural gas as a feedstock, phosphate manufacturing relies centrally on two key components: phosphate rock and sulfur, combined with anhydrous ammonia to supply the nitrogen component.
Of these raw ingredients, sulfur has emerged as the most volatile input. Because sulfur is primarily produced as a byproduct of petroleum and gas refining, disruptions in the energy sector directly limit sulfur availability. High energy prices, trade policy disputes, and widespread conflict have severely pressured global sulfur supplies.
Persistent Upward Price Momentum
Paulson outlined sulfur’s steep price trajectory over the past two years:
- Early 2024: Sulfur traded below $100 per ton.
- Throughout 2025: Prices climbed steadily, reaching $300 to $400 per ton.
- Spring to Late Summer 2026: Prices surged from $400–$450 per ton in early March to more than $1,000 per ton by mid-summer.
A significant share of globally traded sulfur originates in the Middle East and must pass through maritime bottlenecks such as the Strait of Hormuz. War in the region, coupled with infrastructure damage at refining and processing facilities, has choked supply lines. Because refining infrastructure cannot be restored rapidly, Paulson cautioned that sulfur price pressures are likely to linger across multiple years rather than resolve quickly. Even though the United States produces considerable volumes of sulfur domestically, it remains linked to global commodity pricing shocks.
Decision Points for Farmers This Fall
The full impact of $1,000-per-ton sulfur may not yet be completely reflected in current retail DAP and MAP pricing, suggesting a higher-than-average probability that phosphate prices could climb further rather than pull back.
This environment leaves growers facing tough risk-management decisions heading into fall application:
- Evaluate Soil Reserves: Unlike nitrogen, phosphate applications can occasionally be delayed by utilizing existing soil reserves, giving producers leeway if soil tests show adequate fertility levels.
- Weigh the Risk of Delay: Postponing applications carries the risk of facing even higher fertilizer prices next season if manufacturing adjustments and geopolitical pressures continue to elevate costs.
- Rely on Soil Testing: Rather than blanket applying or guessing replacement rates, farmers should use recent soil test results to apply only what is strictly necessary to maintain desired nutrient targets.
Detailed agronomic strategies for managing phosphate rates and interpreting soil test levels ahead of fall field work will be addressed by University of Illinois soil fertility specialist John Jones. Producers can review the complete economic analysis penned by Paulson, Gary Schnitkey, and Carl Zulauf by visiting farmdocdaily.illinois.edu.
