Prairie strips show promise as effective conservation tool
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Published
4/8/2015
“We’ve seen dramatic environmental improvements with as little as 10 percent of the land in prairie strips placed on the contours of row-cropped watersheds,” said Lisa Schulte Moore, associate professor of natural resource ecology and management at Iowa State University (ISU).
Improvements from strategically placed prairie strips include a 95 percent reduction in sediment transport, 90 percent reduction in phosphorus and total nitrogen transport and 60 percent reduction of surface water flow from ISU’s experimental sites, which are cropped on a corn-soybean rotation using no-till. Positive results can be measured in the first year after a prairie strip is installed.
This spring, the ISU project team is working with the Iowa Department of Agriculture and Land Stewardship (IDALS) and the U.S. Department of Agriculture’s Natural Resources Conservation Service to add 25 prairie strip demonstration sites at commercial farms across Iowa, along with the Whiterock Conservancy near Coon Rapids and Cedar Rapids’ Eastern Iowa Airport.
Tim Smith, who farms 800 acres near Eagle Grove, is participating in one of the 2015 demonstration sites. “Our most precious assets are our soil and water, and we need to protect them,” he said. “The more I heard about the benefits of prairie strips, the more I wanted to try them on my farm.”
Keeping soil, nutrients in place
Prairie strips are placed perpendicular to the flow of water with spacing and configuration designed to fit farming and machinery needs. There is the potential that the strips can be moved as sediment is deposited on the upslope edge or machinery needs change, making them a flexible alternative to terraces for certain slopes and soil types.
“Prairie strips could involve as little as 1 percent of the land in a field or 10 to 15 percent or more, depending on the topography and soil type,” said Schulte Moore, who is working closely with landowners to determine how many acres of prairie strips are needed on various soil types.
Prairie strips include a diverse mix of warm-season and cool-season native grasses, along with wildflowers. The stiff, upright stems and deep roots of prairie plants slow the flow of water and encourage infiltration, keeping soil and nutrients in the field where they are needed. With minimal upkeep, diverse prairie communities are able to withstand drought and intense rain.
It’s a plus that prairie strips rank among the least expensive in-field management practices. “They cost approximately $40 per treated acre per year for establishment and management,” said Matt Helmers, an ISU Extension agricultural engineer, who noted this cost is spread over a 15-year average.
Prairie strips can include big bluestem, Canada anemone, black-eyed Susan, partridge pea and more, along with early-season plants that benefit pollinators.
Smith said he is also seeding extra milkweed in his prairie strips for monarch butterflies, which depend on milkweed for nutrition. In addition, Smith has Conservation Reserve Program (CRP) ground with filter strips along with 550 acres of cover crops.
Part of conservation tool box
Cost-share funding for prairie strips is available through various programs, including the Environmental Quality Incentives Program (EQIP). Smith received a grant from Trees Forever to help install his prairie strips. “I view conservation as a total system,” he said. “Prairie strips can be an important part of this system.”
Prairie strips show that farmers can find cost-effective solutions that provide substantial environmental benefits while ensuring good crop production. “We’re really excited about prairie strips’ potential,” Schulte Moore said. “They could become a major tool in the toolbox to provide a practical solution for helping Iowa farmers meet conservation and yield objectives.”
For more information about ISU’s prairie strip research, log onto www.nrem.iastate.edu/research/STRIPs.
Maulsby is a freelance writer in Lake City.