Diesel Prices Are Surging, But a Bigger Fertilizer Crisis Could Be Right Behind It

Mon, 14 Sep 2026 19:19:36 GMT

Diesel prices are climbing fast, and farmers are feeling it in real time. U.S. diesel prices have surged 60% since the start of the war in Iran. With another 30 cent jump in just a week, the national average for diesel stands at $6.18 per gallon. It’s adding fuel to inflation, and for farmers, it’s hitting at the worst possible time, right in the middle of harvest.

But diesel may not be the only input keeping farmers up at night this fall. Fertilizer prices are climbing too, and there are warning signs that a much bigger crisis could be forming beneath the surface, as a sulfur shortage could be next. Sulfur is a key ingredient used in inputs like phosphate, and one major fertilizer supplier says farmers could face more than just higher prices. If the situation doesn’t improve, they may not be able to find it at all.

The Next Crisis Could Be Sulfur

As farmers look at higher fall fertilizer prices for essential inputs, including anhydrous ammonia, one fertilizer that farmers may not be watching closely enough, yet, is sulphur.

Ben Pratt, vice president of public affairs for Mosaic Company, says sulfur prices have blown past anything he’s seen in his career.

“I’ve been at Mosaic 15 years, and in all that time, sulfur has typically traded somewhere between $100 and $300 a ton,” Pratt says. “At this moment, because of the closure of the Strait of Hormuz and other conflicts rattling the world, sulfur prices are well north of $1,000 a ton. They’ve multiplied fivefold.”

Sulfur is the raw material that makes phosphate fertilizer possible. Pratt says every ton of phosphate Mosaic produces requires four-tenths of a ton of sulfur.

“So if we don’t have sulfur, we can’t make phosphate fertilizer, period,” Pratt says.

That math showed up in Mosaic’s latest earnings report, with revenue down about 6% year over year. Pratt says the company has had to idle plants because production isn’t profitable at today’s sulfur pricess, including a facility in Louisiana, a partial idling of a large Florida plant, and most of its phosphate production in Brazil.

From Higher Prices to an Actual Shortage

Is this just a price problem, or could farmers be looking at an outright phosphate shortage? Pratt says due to the lack of sulphur available today, phosphate production has been severely slashed.

“Let’s just talk numbers for one second,” Pratt says. “Typically, the global phosphate fertilizer market every year is 75 million tons. That’s how much phosphate fertilizer global farmers consume every year. Our best estimates are that producers around the world will probably make about 45 million tons this year, because they either can’t get or can’t afford sulfur. There is a looming crisis out there, and it’s not too far removed, it becomes a food crisis.”

Pratt says that means farmers should not just brace for higher phosphate fertilizer prices in the months ahead, but also the possibility that some areas may see a shortage.

“They could be looking at higher fertilizer prices, or they could be not able to find it at all,” Pratt says. “If we’re not able to produce phosphate fertilizers here, and our big competitors in other parts of the world are either slowed down or not producing, that’s a pretty dire situation.”

And the tension in the Strait of Hormuz and the Black Sea doesn’t seem to be easing anytime soon , meaning the sulfur squeeze could get worse before it gets better.

The Flip Side of Higher Grain Prices

Here’s the uncomfortable irony in all of this: the same global disruptions partially boosting grain prices over the past month, could also be setting up a yield problem down the road.

“I think this is one of the reasons that drive grain prices up, is the expectation that yields around the world are going to suffer because there won’t be enough fertilizer,” Pratt says.

He says the possible food supply crisis isn’t just a headline, it’s now a real risk.

Anhydrous Prices Are Also Climbing Fast

It’s not just phosphate seeing a surge in prices. One Missouri retailer told U.S. Farm Report in early September that farmers looking to book anhydrous ammonia right now are paying $950 a ton. Back in February, it was around $875. And at the end of last year, anhydrous was hovering closer to $770 a ton. And there’s talk prices

Josh Linville, who tracks fertilizer markets for StoneX, says the run-up starts with supply.

“We’re starting out with supplies tight,” Linville says. “When we look at our fertilizer year, starting inventories, and that starts on July 1st, we thought they were snug. We underestimated how tight they were.”

Linville says it’s not one problem causing the price spike. He says it’s several, stacking on top of each other around the globe.

“We went to the summer, grain prices were terrible and fertilizer prices were terribly high,” Linville says “Unfortunately, there’s so many problems around the world. Depending on what product you’re talking about, you talk about nitrogen, it’s a Strait to Hormuz, it’s Russia-Ukraine war, it’s European production issues.”

For years, nitrogen prices tracked natural gas prices in lockstep. That relationship still holds, just not with the natural gas benchmark most Americans watch.

“There’s still a decent correlation to natural gas, just not the Henry Hub, not the U.S. gas,” Linville explains. “The correlation is honestly tighter to the Dutch TTF over in Europe, because Europe is our swing producer around the world. Right now their values are closing in on $25, when normal is $4, $5 or $6. There’s a chance we lose more production over there. And if they lose their production, they’re going to start calling for more tons. The U.S. is a natural supplier over there.”

Is This Manipulation or the Just the Market?

Mosaic is one of the fertilizer companies that’s been in the crosshairs of this administration’s trade actions. Mosaic argues the temporarily suspended countervailing duties on Moroccan phosphate are hurting domestic competition; USDA argues the opposite. Either way, fertilizer prices and availability have become a focal point in Washington.

Darren Hudson, the Combest Endowed Chair and director of the International Center for Ag Competitiveness at Texas Tech, says the data doesn’t point to domestic price-fixing.

“That’s always hard to say yes or no. It is probably not, based on looking at the data. It doesn’t appear to be something where the U.S. price is out of alignment from world price,” says Hudson.

Hudson says manipulation typically shows up as a divergence between U.S. prices and global prices. That’s not what’s happening here. Instead, it’s a global production problem creating a domino effect, one where farmers, and everyone else relying on diesel and fertilizer, are the ones paying the price.

Watch the full Farm Journal report as U.S. Farm Report takes a deep dive into the sulfur shortage unfolding, as well as what it means for farmers.