Prairie Strips Improving Soil Health
Returning a small part of Iowa farmland to prairie is bringing a huge number of benefits according to Iowa State University research. The STRIPS project—Science-based Trials of Rowcrops Integrated with Prairie Strips—has proven the benefits of placing prairie strips in Iowa cropland.
“We examined what benefits could be provided by strategically placing about 10 percent of prairie within agricultural watersheds,” says Lisa Schulte Moore, an associate professor of natural resource ecology and management who helped originate the project. “In part we wanted to examine whether the prairie provides greater benefits than the land area it occupies. We call these disproportionate benefits.”
The results recorded at the original test site at the Neal Smith National Wildlife Refuge near Prairie City, Iowa, have documented
- 44 percent reduction in water runoff,
- 95 percent reduction in soil loss,
- 90 percent reduction in phosphorus runoff and
- 84 percent reduction in nitrogen runoff.
Schulte Moore says these benefits have come with no per acre difference in crop yields or weed abundance in the cropped areas of the fields. A bonus: an improved habitat for beneficial insects and wildlife.
The project’s team started work on the concept in 2003, began site identification in 2004 and the strips were seeded in 2007. A diverse mix of plants includes grasses and wildflowers that produce deep root systems and stiff stems, which reduce erosion and runoff by slowing water and holding soil in place.
Over time, there have been about 50 faculty members, scientists, post-docs and graduate students involved in the project. Schulte Moore shares STRIPS leadership with Matt Helmers, in the agricultural and biosystems engineering department, and works with the team to promote the concept through demonstrations and meetings for farmers.
The STRIPS team has helped implement prairie strips on 20 farms in Iowa and one in Missouri. Those include demonstration sites at the Iowa State research farms at Armstrong, McNay, Rhodes and a Committee for Agricultural Development farm south of Ames. Schulte Moore says they are aware of at least three more STRIPS-inspired sites in Iowa.
“We are working with an additional half dozen farmers and farm landowners to implement prairie strips in Iowa this fall, and partners in adjacent states— from Minnesota to Texas and Kansas to Kentucky—also are in the process of implementing prairie strips,” she says.
One of those landowners is Gary Guthrie (’79 pest management and agronomy) near Ames. He installed 4.2 acres of strips last spring on part of an 80-acre field after hearing about the project’s results.
“I have worked in Bolivia and El Salvador. I have seen depleted soils and so I know we need to do everything in our power to maintain the soil and enhance water quality,” he says.
He is marking the 50th anniversary of his family’s ownership of the farm with the strips creation as well as implementing no-till management and cover crops.
“We need considerably more diversity in our Iowa landscape to break some of our pest and disease cycles,” Guthrie says, “I believe the prairie strips are a small part of that.”
The STRIPS project recorded a doubling of the number of birds and bird species using the areas with prairie strips compared with those in row crops. Evidence also suggests the strips could provide habitat for pollinators and other beneficial insects.
“These results need to be placed in context, however, as our initial experiment was conducted within the boundaries of a wildlife refuge that has lots of great habitat,” Schulte Moore says. “This is one of the reasons why our second phase of research, which is being conducted in agricultural settings more typical of Iowa, is so important.”
Several recent federal, state and foundation grants—including from the U.S. Department of Agriculture Farm
Services Agency and National Institute of Food and Agriculture (USDA-NIFA), Iowa Department of Agriculture and Land Stewardship, Leopold Center for Sustainable Agriculture, McKnight Foundation and Walton Family Foundation—will help the program expand its mission. The three-year, $500,000 grant from NIFA will allow
the program to widen its scope and test its methods in new geographic areas and agricultural practices.
STRIPS also represents a collaboration between the regent’s universities, Schulte Moore says. The Tallgrass Prairie Center at the University of Northern Iowa, which provides information on how to establish and manage on-farm prairies, is now providing technical service for implementing prairie strips on farms and hosted field days this season with Iowa State University staff. And biomass material harvested from the prairie strips at the Eastern Iowa Airport will be burned by the University of Iowa’s energy plant through its Biomass Energy Initiative.