Leopold Center for Sustainable Agriculture

Researchers evaluate canola as a 'third' Iowa crop

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By MELISSA LAMBERTON, Communications research assistant

As winter approaches, the green and gold patchwork of corn and soybean fields disappears from Iowa’s landscape, leaving vast tracts of bare farmland. The state’s two dominant crops are summer annuals that expose soil to erosion, nutrient loss and weed invasion during the rest of the year. A project funded by the Leopold Center’s Ecology Initiative hopes to change that with canola, a winter annual and a potential “third” crop for Iowa agriculture.

Mary Wiedenhoeft, professor in agronomy at Iowa State University, initiated the project in 2009 with Stefan Gailans, a Ph.D. student in ISU’s Graduate Program for Sustainable Agriculture. They hope to determine whether a winter or spring variety of canola is more suitable for Iowa agriculture.
“Canola is quite foreign to Iowa, so one of the major aspects of this project is that it’s an example of alternatives that farmers can look to when they want to try something different on their own farm,” Gailans said.

The researchers established three different cropping rotations: conventional corn/soybean and two alternatives with spring and winter varieties of canola (see table). In the alternative systems, the canola is double-cropped with either spring or winter wheat and interseeded with red clover, a perennial legume that provides nitrogen to subsequent crops in the rotation.

The source of healthful vegetable oil, canola offers farmers a marketable annual crop that helps protect ecosystem resources. Increasing crop diversity—specifically, with annuals that fill in the gaps when corn and soybean aren’t growing, or with perennial species—can help interrupt weed cycles, reduce pests and mitigate erosion from wind and water.

Canola can offer economic benefits, too. It actively takes up sunlight and nutrients during times of year when corn and soybean aren’t growing. That allows farmers to take advantage of spring and fall growing seasons, generating revenue while keeping more cover on the ground. The additional nitrogen and organic matter held in the soil improves next year’s corn crop, and the added diversity makes the farm more resilient in the face of shifting market forces.   

A canola oil processing facility already exists in Cherokee, Iowa, and canola prices generally have been increasing over the last decade.

“I grew up on a farm in Iowa,” Wiedenhoeft said. “I really want agriculture to be able to continue in Iowa. I want it to be productive but I also want it to be sustainable in relationship to the environment.”

Back to Leopold Letter Fall 2011