Fertilizer Costs Firm Into the US Fall Window as Nitrogen and Phosphate Tighten Ahead of Harvest
US retail fertilizer prices rose for six of eight major nutrients in the second full week of September, with anhydrous ammonia running 22% above a year earlier, while heavy rain across the western corn and soybean belts complicates the start of harvest and the fall application schedule.
DTN's weekly retail survey for the second full week of September 2026 showed six of eight tracked fertilizers higher than a month earlier and none moving 5% or more, the threshold DTN treats as significant, for a second consecutive week. DAP averaged $925 a ton, MAP $967, potash $495, 10-34-0 liquid $718, anhydrous ammonia $945 and UAN32 $458, while urea at $659 and UAN28 at $421 were the only two nutrients to ease. On a per-pound-of-nitrogen basis urea averaged $0.72, anhydrous $0.58, UAN28 $0.76 and UAN32 $0.72.
The year-over-year picture is where the pressure shows. Seven of the eight nutrients now cost more than in September 2025, led by anhydrous ammonia up 22%, with 10-34-0 up 8%, MAP up 5%, DAP and potash up 2% and urea up 6%; only UAN32 is cheaper, down 3%. Independent US retail tracking puts urea 46-0-0 at $907.80 a short ton with a 90-day gain of 24.4% and ammonium sulfate at $770.20, up 27.3% over the same 90 days, while anhydrous ammonia has retraced about 10.5% in the most recent week from a higher peak.
Supply, not demand, is doing the work. StoneX fertilizer vice president Josh Linville noted that a proposed US arrangement to import Belarusian potash would have limited effect because Lithuanian, Latvian, Polish and Ukrainian transit routes remain closed and Russian corridors can only move limited tonnage, and argued the market needs relief in phosphate and nitrogen rather than potash. Chinese export restrictions on phosphate rock and processed phosphates have constrained global phosphate supply through much of 2026, while nitrogen costs remain levered to natural gas and petrochemical feedstock markets disrupted earlier this year.
Weather adds a timing risk. USDA meteorologist Brad Rippey said heavy rains over the past week were affecting areas of the western corn and soybean belts, a pattern that can delay field work and compress the window in which growers can apply fall nitrogen and phosphate. With row-crop margins already thin to negative for a fourth consecutive year, a 6% to 22% increase in nutrient costs against last season raises the likelihood of reduced application rates or a shift toward crops with lower fertility requirements for 2027.