Global oil and gas prices have skyrocketed following the US attack on Iran last weekend. But another key global supply chain is also at risk, one that may directly impact American farmers who have already been squeezed for months by tariff wars. The conflict in the Middle East is choking global supplies of fertilizer right before the crucial spring planting season.

“This literally could not be happening at a worse time,” says Josh Linville, the vice president of fertilizer at financial services company StoneX.

The global fertilizer market focuses on three main macronutrients: phosphates, nitrogen, and potash. All of them are produced in different ways, with different countries leading in exports. Farmers consider a variety of factors, including crop type and soil conditions, when deciding which of these types of fertilizer to apply to their fields.

Potash and phosphates are both mined from different kinds of natural deposits; nitrogen fertilizers, by contrast, are produced with natural gas. QatarLNG, a subsidiary of Qatar Energy, a state-run oil and gas company, said on Monday that it would halt production following drone strikes on some of its facilities. This effectively took nearly a fifth of the world’s natural gas supply offline, causing gas prices in Europe to spike.

That shutdown puts supplies of urea, a popular type of nitrogen fertilizer, particularly at risk. On Tuesday, Qatar Energy said that it would also stop production of downstream products, including urea. Qatar was the second-largest exporter of urea in 2024. (Iran was the third-largest; it’s also a key exporter of ammonia, another type of nitrogen fertilizer.) Prices on urea sold in the US out of New Orleans, a key commodity port, were up nearly 15 percent on Monday compared to prices last week, according to data provided by Linville to WIRED. The blockage of the Strait of Hormuz is also preventing other countries in the region from exporting nitrogen products.

“When we look at ammonia, we’re looking at almost 30 percent of global production being either involved or at risk in this conflict,” says Veronica Nigh, a senior economist at the Fertilizer Institute, a US-based industry advocacy organization. “It gets worse when we think about urea. Urea is almost 50 percent.”

Other types of fertilizer are also at risk. Saudi Arabia, Nigh says, supplies about 40 percent of all US phosphate imports; taking them out of the equation for more than a few days could create “a really challenging situation” for the US. Other countries in the region, including Jordan, Egypt, and Israel, also play a big role in these markets.

“We are already hearing reports that some of those Persian Gulf manufacturers are shutting down production, because they’re saying, ‘I have a finite amount of storage for my supply,’” Linville says. “‘Once I reach the top of it, I can’t do anything else. So I’m going to shut down my production in order to make sure I don’t go over above that.’”

Conflict in the strait has intensified in the early part of this week, as the Islamic Revolutionary Guard Corps have reportedly threatened any ship passing through the strait. Traffic has slowed to a crawl. The Trump administration announced initiatives on Tuesday meant to protect oil tankers traveling through the strait, including providing a naval escort. Even if those initiatives succeed—which the shipping industry has expressed doubt about—much of the initial energy will probably go toward shepherding oil and gas assets out of the region.

“Fertilizer is not going to be the most valuable thing that’s gonna transit the strait,” says Nigh.