By Ed White and Sumit Saha

WINNIPEG, MANITOBA, May 7 (Reuters) - High fertilizer prices will remain for months and probably into 2027 regardless of how soon the Iran war ends, the world's biggest potash producer says.

And despite high prices for all fertilizers even before the Iran conflict began, American farmers are not cutting back on nitrogen and potash, Nutrien President Ken Seitz told his company's first-quarter results call.

"We are not seeing that," said Seitz about strong global potash demand and expected nitrogen fertilizer use for this year's U.S. planting season. "Farmers are looking to maximize yield."

Nutrien delivered better-than-expected earnings on its Q1 potash and nitrogen fertilizer sales, but said phosphate earnings have been hit by soaring sulfur prices. Sulfur is a key component in phosphate making and high prices are expected to crimp phosphate margins for an extended time.

Global fertilizer prices have been pushed higher by the Iran war, with the Middle Eastern Gulf providing more than 30% of the world's urea nitrogen fertilizer, and about 25% of both world ammonia and sulfur exports.

That has been hurting farmers who needed to buy nitrogen and phosphate fertilizers in the last two months and is worrying Southern Hemisphere farmers who will soon need to purchase fertilizer for their next crop.

Seitz said it is impossible to predict how long it will take for Gulf fertilizer, natural gas and sulfur shipments to return to pre-war levels, since some facilities have been damaged, the shipping situation is a mess, and restarting production facilities can be difficult.

Nutrien is not planning to restart its Trinidad nitrogen fertilizer facilities, Seitz said. Struggles with natural gas supplies and port access made the company shut them down in 2025. The company is focused on selling them, Seitz said.