Bare soil is a common sight in Iowa in the wintertime. Corn and soybeans, Iowa's dominant cropping systems, are summer annuals that leave soil exposed to erosion, nutrient loss and weed invasion during the rest of the year. A project funded by the Leopold Center for Sustainable Agriculture at Iowa State University 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 Ph.D. student Stefan Gailans. The project is featured in the Leopold Center's latest video, On the Ground with the Leopold Center.
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 a perennial species, can help interrupt weed cycles, reduce pests and mitigate soil erosion from wind and water.
Canola has economic viability as well as environmental benefits
To study canola's economic viability and environmental benefits, the ISU research team established three different cropping rotations: conventional corn/soybean and two alternatives with spring and winter varieties of canola. In the alternative systems, the canola is double-cropped with either spring or winter wheat and interseeded with red clover.
Canola actively takes up sunlight and nutrients during times of year when corn and soybeans 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 to changing market forces.
"I grew up on a farm in Iowa," says Wiedenhoeft. "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."