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Trials pit prairie grass against runoff

Cover crops are getting a lot of attention lately, and for good reason; they're a way to sustain soils, prevent erosion, and provide a home for better crop yields. Now there's a new player in the conservation game, and it doesn't stray far from what was once the most common resident of the soils in much of the nation's center.

A farmer in southwest Iowa is turning to native prairie grasses to foster better conservation on his farm. Yet the grasses are just a part of a broader system in the 50 acres he's testing on his Taylor County, Iowa, farm.

In late June, Seth Watkins planted this small plot to strips of prairie grass as part of the Science-based Trials of Rowcrops Integrated with Prairies (STRIPs) program operated at Iowa State University. The system, which research shows could reduce the amount of sediment runoff from farm fields by up to 90%, uses the deep roots and rigid stems of the native grasses to trap the sediment that would otherwise run off and create problems like erosion ruts and heavy algae growth in a pond adjacent to the acres where Watkins planted the grasses.

“My hope is that if the strips work as well as I believe, the ruts will go away and the pond will be clear again,” he says in a report from the Leopold Center for Sustainable Agriculture at Iowa State University.

Watkins operates 2,800 crop acres and a 600-head cow-calf operation in the rolling hills of southwest Iowa, land that is best suited for this type of system, experts say. It's not immediate, though; it takes time for the grasses to get established and start developing root systems that can trap sediment.

"Prairie plants spend their first few years putting more roots in the ground than shoots in the air," says Iowa State University agronomist Matt Liebman. "You have to control weed competition, typically by mowing in the first year or two."

If you're interested in trying a system like the one Watkins is introducing on his farm, Liebman recommends contacting your local Natural Resources Conservation Service (NRCS) office and asking for information on the "contour buffer strip standard" and "filter strip standard for hillsides and sloping land."

Looking down the road, NRCS conservationist Doug Davenport says this type of system will allow land to remain in production while making a considerable dent in the amount of nutrient and sediment runoff from crop acres. Research thus far has shown that planting 10% to 20% of a watershed to prairie grass can almost completely eliminate this type of runoff.

"We've never had the best land use be something people could actually make a living doing," Davenport says.

“My gut tells me it’s a good practice," Watkins says. "If other people are going to buy in, they’re going to need some hard data."

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