Field of Dreams: Healthy soils are a necessity for agriculture and water quality in Iowa

During the recent nationally televised baseball game at the Dyersville Field of Dreams, the gorgeous aerial views of Iowa’s expansive, emerald fields of corn elicited a sense of pride in many of us. We truly live in a special place, where farming is the lifeblood of the state and a source of so much bounty.

Earlier that same week, I had read about the auction of 2,000 acres of prime Iowa farmland placed under a permanent conservation easement by the well-known Garst family. It provided us with one example of what it is going to take for Iowa to maintain that agricultural productivity, while protecting its waters and remaining native ecosystems.

Of course, few have the resources of the Garsts. But in truth, many ordinary Iowa farmers of modest means are improving their land through the use of soil health practices like no-till farming, cover crops, rotational grazing, and others. They are still a minority, but they have found tremendous benefits in the increased resiliency of their crops and pastures during drought and the resistance of their soils to erosion during Iowa downpours. They’ve spent less on fuel and fertilizer, and many have enjoyed higher crop yields than their county averages.

Prior to large-scale agriculture, Iowa had some of the best soils on Earth. But our cultivated topsoils have lost on average half their original thickness and Iowa continues to lead the nation in the rate of soil erosion from agriculture by a significant margin.

To protect what is left and to begin to reverse that loss, soil health practices need to become the rule rather than the exception. Such practices regenerate the soil by building organic matter and by increasing the amount of porosity (tiny open pathways) in the topsoil, which is critically needed so rainwater can seep into the ground rather than becoming runoff that carries sediment, fertilizers and pesticides to Iowa’s streams.

Plowing and discing before planting a crop damages soils and inhibits the infiltration of water. No-till prevents such damage, and planting cover crops after the harvest builds soil organic matter. Organic matter is terrific at holding onto water in the topsoil for gradual use by plants, and it is critical for maintaining soil fertility, thereby reducing the need for nitrogen fertilizer.

The latest data show that from July 2018 to June 2019, Iowa farmers applied slightly more than two billion pounds of nitrogen fertilizer, the chief source of the nitrates that are polluting our rivers and drinking water. This is simply an unsustainable and destructive way of nourishing crops. Furthermore, building organic matter with cover crops also sequesters carbon in the soil — which reduces carbon dioxide in the atmosphere — and provides habitat for pollinators.

Organizations like the Practical Farmers of Iowa, Midwest Cover Crops Council and several others have been educating farmers about no-till and cover crops for many years. The Iowa Farm Bureau encourages the use of no-till but needs to do much more to promote cover crops. One-third of Iowa fields are currently under no-till, and only about 4 percent are planted in cover crops. It’s definitely progress. But both these numbers must increase significantly statewide through both voluntary efforts, and regulatory action if necessary.

Healthy soils are the only way forward to having both clean water and farms that are productive and resilient to extreme weather events in an unpredictable future.

Kathleen Woida, Ph.D., is a former state geologist for the USDA’s Natural Resources Conservation Service in Iowa, and author of “Iowa’s Remarkable Soils: The Story of Our Most Vital Resource and How We Can Save It,” University of Iowa Press, 2021. kathleen-woida@uiowa.edu