Traditional buffer strips of cool season grasses or single warm season native grasses help control soil erosion, but when several dozen species of native prairie plants are thrown into the mix, the diversity of a slice of prairie blossoms into multiple benefits. Sponge-like water infiltration, top-notch habitat for pollinators, prime soil building conditions, new habitat for songbirds and other wildlife, and better water quality are among the expanded benefits.
A prairie strip may be coming to a corn or soybean field near you. Slowly but surely, demonstration prairie strips established with help from Iowa State University and others are appearing across the landscape in Iowa. And they’re catching on in Missouri, Illinois, Wisconsin, and Michigan. All these states have prairie strips on the ground based upon the work done at ISU.
Like most of the farmer early adopters of the practice, Larry and Margaret Stone, and Margaret’s brothers Dick and Bill Keith, installed contour prairie strips first and foremost for conservation purposes on a 37-acre sloping field just west of Traer, Iowa. But a quick look at their striking, parallel strips shows that strategically placed native prairie strips in corn and soybean fields can be as much an economic benefit as they are an environmental fit.
Strips get CRP benefit
“We’ve always been interested in prairie, and especially like the 90% reductions in soil and nutrient losses from the field,” Larry says. Two years ago, the Stones seeded and entered 5.5 acres of contour strips into a 10-year Conservation Reserve Program (CRP) contract as contour buffer strips, practice CP15A.
When native prairie strips can fit into buffer strips or other CRP practice guidelines, the cost/benefit ratio for prairie strips changes dramatically. In the Stone’s case, they receive annual CRP payments of $311.43/acre on the land seeded to prairie strips for 10 years. “Could you do better with $7 corn and $15 beans?” Stone asks. “Probably. But if the corn price turns out to be $3 a bushel and soybeans are $8 a bushel, CRP will look like a very good deal financially. And we know it’s a good thing for the long-term health of the land.”
The Stones’ tenant, David McKinley, was agreeable and involved in setting up the strips. The new layout didn’t exactly match the previous contour pattern but fits the hillside well. “I've teased David that we might be doing him a favor by taking 5.5 acres of crop away from him,” Stone says. “With crop prices in the dumps this year, it may be hard to break even raising corn or beans.”
The strips are progressing as the Stones expected they would at this point. “We did a frost seeding, dropping seed on top of the snow in January of 2016. The seed worked down through the snow and germinated and came up,” Stone says. “There have been a few weeds but we mowed it a lot early on and the prairie plants are taking over now. We’re rebuilding the soil where those plants have taken root, and that has a value, too.”
The Stones hired Carl Kurtz to seed the strips with what’s called the Carl Kurtz mix, containing dozens of native prairie species. “The more diversity, the better,” Stone says. “That has all kinds of advantages, for soil building, pollinators, water quality, wildlife, and more reasons. We expect the strips will be good nesting cover for songbirds and pheasants.”
A summer class of University of Northern Iowa students led by biology professor Ai Wen found 17 species of flowering plants in the Stone strips. “That’s a well-established prairie in a short time. Larry did a good job of mowing to keep weeds down and allow the prairie plants to thrive,” Wen says.
ISU professor Dr. Mary Harris, one of the principal investigators on the STRIPS team, is researching native (wild) bee use of prairie strips in Iowa. She’s helped document 300 species of native bees in Iowa, and recently found 47 bee species on Jerry Peckumn’s strip of prairie planting on his farm in central Iowa. “Jerry has a diversity of plants, and that’s what you need for pollinators,” Harris says. “You want to have 5 to 10 plants flowering at any one time to support a diversity of bees.”
Peckumn planted switchgrass 20 years ago, but replanted with a mixture of dozens of prairie plant species 8 years ago when he realized he would get more from a diverse prairie planting. He’s excited to have so many bees on the farm. “Flowers bloom all through the summer in that prairie, and that brings bees and butterflies,” he says. “Mary says the native bees are just as efficient at pollinating as honey bees.”
Reduced runoff benefits
The 200-acre farm has been in Margaret Stone’s family since the 1860’s. “It would qualify as a heritage farm if we ever did the paperwork,” Stone says. “Some of the land is in the wetland reserve, but 150 acres are cropland. The prairie strips made the most sense on this field because of its steep slopes. If we see the benefits we expect to see, reducing runoff, increasing organic matter, and more pollinator and wildlife benefits, the strips may be part of our cropping system for a long time to come,” Stone says. “We haven’t ruled out doing more prairie strips.”
The Stone prairie strips field is one of 33 prairie strips demonstration sites in Iowa, according to Tim Youngquist, a farmer liaison for the STRIPS program for Iowa State University. Youngquist says there are many more in the planning stage that will go in this fall and next spring.
Youngquist has helped farmers think through all aspects of using prairie strips, and is available to assist Iowa farmers who are considering installing strips. He’ll soon have a lot of help. A series of recent training meetings for technical service providers and certified crop advisors is leading to a cadre of certified prairie strips consultants—soon to be listed on the ISU STRIPS website—who will help farmers across the state. There is no prairie strips conservation practice in the NRCS technical guide, but ISU is working with NRCS to develop guidance on using multiple NRCS conservation practice codes like filter strip, contour buffer, habitat buffer, and pollinator habitat to establish prairie strips.
Seeking more farmers
Iowa State University has done extensive research on the value of prairie strips and their effects on the environment (see Corn+Soybean Digest story from April 2015)
ISU researchers are still looking for farmers who are willing to collaborate on research to learn more about how prairie strips work. “We’re seeing the start of a prairie strips community. We’ve learned a great deal from our collaborators and want to keep advancing the science by installing strips on new landscapes,” Youngquist says. “For instance, we recently used the services of an underground televising company to run cameras up tile lines under 10-year-old mature prairie and continuous corn fields. We found that there was no more intrusion into the tile under the prairie than what was in the continuous corn fields. This is great news because root intrusion into tile lines is often brought up as a reason to be wary of putting deep rooted perennials into a tile drained field.”
See more detailed information on ISU’s STRIPS website.
Water quality benefits
ISU research on prairie strips shows deep-rooted prairie plants increase soil organic matter and improve infiltration, while their stiff, upright stems slow surface runoff and help hold soil in place during rain events. Planting just 10% of a row-cropped watershed in native prairie, strategically located on the contours and foot slope, reduces sediment transport by 95% compared to cropland without prairie strips. Prairie strips protect water quality, reducing nitrogen and phosphorus transport by 90%.
Prairie strips can result in twice the number of bird species and three times their abundance, and the plant diversity brings natural predators of crop pests to the field.