The use of synthetic nitrogen and manure fertilizer on Iowa’s 22.7 million acres of corn and soybeans has increased dramatically over the last four decades. So too has the amount of nitrogen that runs off farm fields into waterways, including the state's groundwater sources.
If current trends continue, Iowa will spend between $41 and $333 million over the next five years for continued nitrate removal from drinking water. Nearly three-quarters of this expense is borne by small rural communities.
Preventing this pollution at its source is possible and starts with reducing overapplication of nitrogen fertilizer and improving management of animal manure. Farmers can also adopt science-based farm practices—such as planting cover crops or perennial buffer strips, reducing tillage, incorporating diverse grains into the traditional crop rotations, and integrating livestock and crop production—that build up soil health while reducing the amount of nitrogen that runs off their land.
State and federal policies, including those promoting research, technical assistance, and incentives, are needed to help Iowa’s farmers adopt such practices on a large scale.
Citation
Boehm, Rebecca. 2021. Dirty Water, Degraded Soil: The Steep Costs of Farm Pollution, and How Iowans Can Fix It Together. Cambridge, MA: Union of Concerned Scientists. https://www.ucsusa.org/node/13929
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