Every year, Midwestern farmers have to apply fertilizer and every year the price of it seems to go up.

Fertilizer accounted for more than 30 percent of the input costs in the last growing season, according to information from the office of U.S. Sen. Charles Grassley, the Republican who is Iowa’s senior senator.

He is joining fellow senators Joni Ernst, R-Iowa, and Tammy Baldwin, D-Wisconsin, on legislation that would require the U.S. Department of Agriculture to look into fertilizer pricing. That agency would be required to report its findings to Congress within one year of the measure being signed.

“Farmers’ bottom lines thin as the price of fertilizer rises,” said Grassley, who is a farmer.

“With fertilizer being one of the ag industry’s highest input costs, it’s problematic farmers have such a limited window into market fluctuations,” he added. “Our bill will provide farmers in Iowa and across the Heartland with needed transparency and certainty as they navigate production costs.”

Ernst placed at least some of the blame for rising fertilizer costs on Democratic President Joe Biden.

“Bidennomics has been tough on all Iowans, especially our farmers and rural communities,” she said in a written statement. “On top of rising prices for everyday goods, Iowa’s ag community is facing all-time high fertilizer costs. Sen. Chuck Grassley and I are teaming up to force Biden’s USDA to create more transparency around why fertilizer costs are so high and how we can work to bring them down.”

The bill introduced by the three senators is called the Fertilizer Research Act. It is endorsed by the Iowa Corn Growers Association and the Iowa Soybean Association, according to Grassley’s office.

According to the bill, the USDA must include these items in its report:

• A description of impacts on the fertilizer market that influence price

• Market trends in the past 25 years

• A description of imported fertilizer market impacts

• Impacts of anti-dumping and countervailing duties

• A study of fertilizer industry concentration

• A study of emerging fertilizer technologies

• An analysis of whether current public price reporting is sufficient for market transparency.