Fertilizer companies are revving their engines, unveiling plans for two big new plants that aim to boost supplies of crop nutrients that have been squeezed by the war in the Middle East.

CF Industries, the largest U.S. producer of nitrogen fertilizer, broke ground yesterday on a $4 billion plant. Separately, farmer co-op CHS and fertilizer maker OCP North America said they plan to build a $450 million production facility focused on phosphate fertilizer.

Fertilizer-linked stocks generally closed lower yesterday. Shares of CF, which have gained about 60% this year, settled 1.2% lower.

Increasing U.S. fertilizer production has been a top priority for Agriculture Secretary Brooke Rollins, who said the USDA helped cut the permiting timeline for CF's plant to help expedite construction. "Probably the most important thing we can do is reshore agriculture," she said.