Planting Perennial Grasses In the Midwest to Reduce Water Pollution

By Jake Miller

Above: The root system of prairie plants compared to those of Kentucky Bluegrass (far left). The root system of prairie plants is very robust and has been shown to improve water quality when planted in a farm landscape. Photo credit: Heidi Natura, Conservation Research Institute

It’s no secret that nitrate runoff in the water supply has negative consequences for humans and wildlife alike. Teams of researchers across the U.S. are exploring ways perennial grasses can help mitigate these effects. 

One of these researchers, Eric Zach, Agriculture Program Manager for the Nebraska Park and Game Commission, and CenUSA Bioenergy Advisory Board Member has been working to help decrease nitrate runoff and improve water quality by planting switchgrass and other native grasses. His goal is simple; plant more perennials to improve water quality to benefit humans, wildlife, and the climate.

Zach and his team focus largely on promoting the use of switchgrass and other native perennials on demonstration plots planted across the Midwest. Their outreach ranges from regular public service announcements to promoting conservation reserve program (CRP) plantings.

Although its conservation benefits are clear, could switchgrass help farmers when planted as a crop?“ There are definitely ways it could benefit the producer,” said Zach. He explained switchgrass, planted on marginal land, could allow farmers to break even or even turn a profit on land that they would normally be losing money on. The switchgrass harvested from marginally productive farmland, could be used as cattle feed, sold as hay, or used as a feedstock for biofuels or bioproducts. In addition, the conservation attributes of the plant, could help prevent nutrients from running off farm fields.

“There’s a cost associated with that runoff,” said Zach. A recent lawsuit by the utilty, Des Moines Waterworks, highlights the issues over nitrate in drinking water and who should pay for water treatment. Three northwest Iowa county drainage districts are being sued by the utility because of excessive nitrate runoff from the Raccoon River, a water source that supplies over 500,000 Iowans with drinking water. 

The strategic integration of perennials into the agricultural landscape could help reduce nitrate pollution and other water quality problems and help restore a healthy, well functioning agricultural system. Native prairie grasses like switchgrass, once common across millions of acres of the Midwest and Great Plains, have thick stems and large root systems that can help reduce soil erosion and nitrate pollution significantly.