American farmers are expected to plant several million fewer acres of corn in 2026 than they did in 2025, as the closure of the Strait of Hormuz throttles a key fertilizer trading corridor, along with the energy and raw materials needed to produce and transport fertilizer.The closure is disrupting deliveries of about one-third of the world’s traded agricultural fertilizers. Fertilizer prices are rising, and farmers worldwide are cutting back on fertilizer use or shifting to less fertilizer-intensive crops.Corn is one of the most fertilizer-intensive and widely grown crops in the United States, but the disruption extends far beyond a single crop or a single nation.AdvertisementAdvertisementThese changes are often discussed as a threat to global food supplies – and they are.But as researchers who study agricultural nutrient cycles and nutrient pollution of our waterways, we suspect that the picture is more complicated, and in some ways more hopeful, than the headlines suggest.That is because decades of farmers using more fertilizer than they needed have quietly built up large reserves of nutrients in the soil, which crops can draw on, even when farmers aren’t applying fertilizer. Indeed, research has shown that in highly intensive agricultural systems, fertilizer application can be cut substantially with little to no effect on crop yields.A legacy of overuseFor decades, farmers in the United States and around the world have steadily increased the amount of fertilizer they use, seeking to produce enough crops to feed a growing population. Despite several years of encouragement to apply less, farmers consistently apply more nitrogen and phosphorus than their crops actually need, our research suggests.AdvertisementAdvertisementThe nutrients that are not taken up by plants accumulate in soils, providing large stores of nitrogen and phosphorus long after they were first applied. They also leach into groundwater or run off into rivers and lakes, driving dangerous algal blooms, coastal dead zones and greenhouse gas emissions.But in the current crisis, they may also serve an unexpected purpose.Excess fertilizer that runs off farmland with rainfall can cause algae blooms, like this one in Lake Erie in 2017. AP Photo/Paul SancyaLatent nutrients in the groundAs shortages and price hikes force farmers to use less fertilizer, crops may be able to draw on legacy nutrient reserves already in the ground.Our analysis of phosphorus use across U.S. croplands found that in parts of the central Midwest and livestock-dominated regions in the East, soil phosphorus reserves are large enough to maintain crop production levels without as much new fertilizer.AdvertisementAdvertisementIn these nutrient-saturated systems, reduc …
