Iowa Lawmakers Push for Fertilizer Pilot Program to Improve Water Quality

By Cami Koons

A bill advanced from the House Agriculture Committee Wednesday that would establish a pilot program to reduce the average, statewide use of commercial nitrogen fertilizer. 

House Study Bill 165 was amended in the committee to task the Iowa Department of Agriculture and Land Stewardship with the administration and development of the pilot program. The program would work with farmers to evaluate crop production strategies that “enhance nitrogen management” in the state. 

Rep. Jon Dunwell, R-Newton, said the amendment calls for a $2 million appropriation from the fiscal year 2026 general fund. This would create a dispersal fund for the program and incentives to participating farmers who would be paid at least $5 per farmed acre that is involved in the program. 

“I appreciate … the way it recognizes farmers who love the land, who love our water, are interested in innovating different ways to make sure that those are protected, as well as enhancing crop production,” Dunwell said in support of the bill. 

Dunwell said the goal of the pilot program is to reduce the statewide average use of commercial nitrogen fertilizers by 15%, or 30 pounds per acre.

An earlier version of the bill tasked IDALS to implement a commercial fertilizer study, rather than a pilot program, to “determine innovations that may be practically incorporated as part of crop production practices.” 

According to a recent study from Iowa State University, the amount of nitrogen fertilizer needed to “maximize the profitability” in corn production has increased by about 1.2%, annually, for the past three decades. 

The study, which looked at corn production in the Midwest, attributes the increased need to the “nutrient demands of higher yields.” 

Researchers said the trend is also likely to continue, and that rising optimum nitrogen rates would be “even higher” if it weren’t for increased use of nutrient efficiency practices like crop rotation, improved drainage, spring fertilizer application, and more informed application tools. 

IDALS recently updated its nutrient reduction strategy, which included several practices aimed specifically at reducing overall nitrogen application. The department also promoted a new, free calculator developed by the Iowa Nitrogen Initiative that helps farmers determine the best rate of nitrogen application for their farm. 

These efforts from IDALS were part of the department’s participation in a larger, 12-state task force to address the growing size of the hypoxia in the Gulf of Mexico by reducing nutrient levels in the Mississippi River Basin.

The efforts also seek to reduce nutrient levels from nonpoint source polluters in Iowa waters. 

Rep. Megan Srinivas, D-Des Moines, championed HSB 165 and its amendment in the committee for the impacts it would have on water in the state. 

“It’s a good bill with a good intention for Iowa’s water quality and … its sustainability for the future,” Srinivas said.

The bill moves next to the full House for debate.

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