WASHINGTON—The Iran war has significantly constrained the global fertilizer trade through the closure of the Strait of Hormuz. It has limited supply, driving up agricultural input prices and affecting planting decisions and crop yields worldwide, ultimately hurting consumers. In particular, the closure has affected nitrogen fertilizer, for which more than 30 percent of global trade passed through the strait before the war. But crops require phosphate and potassium fertilizers, as well. While the strait is not a major chokepoint for these fertilizer types, the global fertilizer market is nonetheless affected, with diammonium phosphate prices up by 10 percent in April, and the price of muriate of potash—a potassium fertilizer—up nearly 20 percent in the first quarter of 2026 compared with a year earlier.
In the United States, nitrogen fertilizer production nearly doubled between 2010 and 2020, and the country is a major global producer of phosphate rock, used to make phosphate fertilizer. For potassium fertilizer, however, the United States is mostly dependent on imports, and its production in the United States has remained stubbornly steady, leading to an increase in imports over time. To ensure US farmers have enough of this important fertilizer for their crops going forward, Washington should advance an internationally minded policy approach toward mined nutrients, paying special attention to a main source of potassium fertilizer—potash.
