Researchers Restore Iowa Farmland to Prairie to Save Water Quality

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As the Iowa Department of Agriculture and Land Stewardship pushes for better conservation practices to improve the quality of Iowa's waterways, farmers and stakeholders are looking for solutions that balance agricultural productivity and smart stewardship. At Iowa State University, scientists are experimenting with one practice that hits all of the above, and is cost-effective.

Most of Iowa used to be prairie, and now, most of Iowa is farmland. With shallower roots, corn and soybeans don't do quite as good a job as tallgrass prairie at keeping the soil together, which leaves both soil and fertilizer vulnerable to washing off the farm. Runoff is money out of a farmer's pocket, and causes headaches for everyone downstream.

But that's where a team of researchers at Iowa State University are exploring the targeted use of the original perennial prairie grass to keep the field on the farm.

Project lead and ISU Associate Professor Lisa Shulte Moore says, "By being really precise about putting the prairie in key places in the landscape, that we can get these disproportionate benefits."

Shulte Moore says the amount of land taken out of production and put into prairie ground doesn't need to be very much. That's what the STRIPS team did at the Neal Smith National Wildlife Refuge in Jasper County in 2008, and the results are surprising.

She says, "By putting 10 percent prairie in, we see a 95 percent reduction in soil loss from agricultural fields. We see a 90 percent reduction in phosphorus loss, an 84 percent reduction in nitrogen loss and a 44 percent reduction in total overland flow."

Reducing runoff keeps costly inputs on the field, but not all of the benefits that the STRIPS team has unearthed are measured in dollars and cents.

ISU Agricultural specialist Tim Youngquist says farmers in the countryside are taking note, "Now, if you're concerned about keeping your nutrients and your soil in the field, I mean, I think that's something that most farmers are concerned about, you can help water quality, you can create habitats for pollinators; you can create habitats for game birds like pheasants, things like that, so, just the nature of the benefits really gets you so much more than what you'd see with a traditional grass buffer or a waterway or something like that."

Since the project's inception ISU researchers have worked closely with the U.S. Fish and Wildlife Service at the Neal Smith Refuge.

FWS Biologist Pauline Drobney says the project was atypical, "It was an odd project, but it seemed to be a good fit, because we're talking about conservation here. And we did, the Refuge staff had a mandate to try to find research that blended conservation and agriculture. So this is a perfect fit that way."

But Drobney says it was difficult to argue with the data. By the end of November, 20 farmers are expected to have implemented prairie strips into their operations.

A trend Youngquist believes will continue, "With the flexibility of the prairie strips and just, you know, making a small change to the landscape and getting that big impact, I think that's going to appeal to a lot of people. So I see it just continuing to expand."

The STRIPS team at Iowa State estimates the average annual cost of treating a field with prairie strips falls somewhere between $24 and $35 per acre. Roughly 90 percent of that price tag is the opportunity cost of taking the land out of production and into prairie strips, but researchers note Conservation Reserve Program contracts from USDA can lower the total cost by as much as 80 percent.