Planting prairie grasses and flowers along edges of crop fields reduces soil loss and chemical runoff

Prairie strips, photographed by Christopher Gannon of Iowa State University

Polluting runoff from farm fields in the Midwest could be mitigated by small patches of native prairie grasses and flowers planted along the edges of fields, say researchers at Iowa State University. “What we've been able to document over a decade worth of research on prairie strips is that by converting just a little bit of that crop area to prairie strips we get very substantial benefits,” ISU professor Lisa Schulte Moore told Amy Mayer of Harvest Public Media.

The benefits include reducing soil loss by 95 percent, reducing phosphorus runoff by 77 percent, reducing overall nitrogen loss by 70 percent, attracting pollinators and increasing the number and diversity of birds. The research was done at 47 farm sites in Iowa, Missouri, Illinois and other states.

Moore's study, published in Proceedings of the National Academy of Sciences, "also included a survey to assess attitudes toward conservation and prairie strips in particular," Mayer reports. "It found strong support for the practice," and not much difference between farmers and non-farmers in Iowa. Farmers' top reasons for supporting the idea are improving water quality and preventing soil loss.

"Farmers have come under increasing pressure to prevent nutrients such as nitrogen and phosphorus, which they apply to fields to enhance crops, from washing off their fields and into streams and rivers," Mayer notes. "Water flowing into the Des Moines Water Works, for example, has required treatment due to unacceptable levels of nitrates. The size of the Gulf of Mexico dead zone, an oxygen-starved area where much aquatic life cannot survive, relates to the amount of farmland nutrients flushing down the Mississippi River from the upper Midwest."