August U.S. wholesale fertilizer prices split sharply between the two workhorse corn inputs, with monoammonium phosphate (MAP) reaching $960 per ton while 28% urea ammonium nitrate solution (UAN28) posted a monthly decline, according to AgroLatam's market reporting.

The split leaves growers, cooperatives and ag retailers heading into fall application with one input line near a multi-year high and another measurably softer than the spring.

What does the MAP price tell us?

MAP is the granular phosphate source most commonly used as a corn starter in row-crop fertility programs. The $960-per-ton wholesale print represents a level that has tightened steadily through the past two seasons as global phosphate supply has been pulled by demand from Brazil, India and North America and constrained by Chinese export quotas and the absence of Russian and Belarusian product from key Western markets.

For application budgeting, MAP at $960 per ton places a meaningful load on variable-cost lines. A fall MAP application at typical agronomic rates of 150 to 200 pounds per acre — a standard starter volume for corn following corn and in variable-rate programs — pushes phosphate-only cost per acre into the $72-to-$96 range before seed, herbicide and nitrogen lines are counted.

The $960 figure also signals that phosphate has decoupled from nitrogen pricing for an extended stretch, an unusual condition for a fertilizer complex that historically moves on correlated global commodity drivers.

Why is UAN28 slipping?

UAN28 is the liquid nitrogen solution used for side-dress and fertigation on corn and as the carrier for many post-emergence herbicide programs. The August decline reported by AgroLatam runs in the opposite direction of phosphate and reflects weaker side-dress demand during the spring and early summer application window. High winds and wet soils in parts of the Corn Belt delayed sidedress timing, depressed in-season demand and allowed retail and wholesale tanks to build.

That inventory build, combined with lower natural gas reference values at Henry Hub through mid-summer, set up the August pullback. UAN28 trades primarily on barge-loaded supply out of the U.S. Gulf and river distribution systems; its economics respond closely to natural gas, ammonia and global urea values.

What the divergence signals

The simultaneous move in opposite directions points to a fertilizer market responding to product-specific fundamentals rather than a single supply shock. Phosphate remains structurally tight; nitrogen has loosened on inventory and energy.

How retailers and growers should read the split

Cooperative and retail buyers of MAP will continue absorbing elevated phosphate costs through fall bookings. UAN28 buyers with spring 2026 needs may have a short window to lock tonnage at lower prices if the August weakness extends into late summer.

What to watch next

The next directional signal for both products will come from the USDA Agricultural Retail Fertilizer Prices report, which surveys dealer-paid prices for ammonia, urea, UAN28, MAP, DAP and potash across the Corn Belt and Cotton Belt. Firming natural gas into Q4 winter heating or renewed Chinese phosphate export restrictions would lift both ends of the complex; softer global phosphate demand from India and Brazil could pull MAP off its high without necessarily pulling UAN28 down further.

For now, the August tape shows a U.S. fertilizer market with two opposing lines in the budget: phosphate firmer than it has been in years, nitrogen easing into fall.