Leopold Center for Sustainable Agriculture

Leopold Center study looks at value of perennials for dealing with climate change

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March 18, 2010

AMES, Iowa -- Global climate change and its effects on crop growing conditions pose major questions for the future on Iowa farms. Researchers at Iowa State University are looking at how perennials (plants that continue growing from year-to-year from the same roots) might be used within annual corn and soybean cropping systems to cope with weather extremes such as more frequent droughts or flooding.

The team hopes that their findings will show how to manage the variations in seasonal water use by different plants as well as document how diversified systems can lead to long-term improvements in water and soil quality. The project is supported by the Ecology Initiative of the Leopold Center for Sustainable Agriculture through a long-term investment begun in 2007.

Matt Helmers, associate professor in agricultural and biosystems engineering, is leading the research project at the Agronomy and Agricultural Engineering Research Farm west of Ames where the perennial crops site was started in 2005.

“We’re trying to understand how different vegetation affects the soil moisture,” he explained. “Right now we think that a mixture of perennial species in waterways, CRP ground and buffers would help reduce runoff during certain rainfall events. If some plants don’t do well under one of the conditions, the ones that do might make up for them.”

The team tests soil moisture in 48 plots every week at six different depths within the plant root system. During the growing season they test more frequently, after each rainfall. The research plots have 16 different combinations of monoculture and diversified plantings including native perennials (big bluestem, stiff goldenrod, false blue indigo Canada wild rye and switchgrass); cool-season grasses (brome grass) and annuals (corn and soybeans with and without winter cover crops).

The water use characteristics of many of the native perennial plants also are being monitored to assess how they use water when compared to the annual crops of corn and soybeans. Researchers hope that the mixture of native perennials among the annuals speeds the process of water infiltration into the soil. This would reduce water runoff that can take with it large amounts of soil and nutrients.

Co-principal investigators on the project are Heidi Asbjornsen, associate professor in the department of natural resource ecology and management, and Amy Kalieta, associate professor of agricultural and biosystems engineering. ISU graduate student Emily Hancheck took measurements and is summarizing three years of information that has been collected for this project. 

For more info contact:

Matt Helmers, Agricultural and Biosystems Engineering, (515) 294- 6717, mhelmers@iastate.edu

Jeri Neal, Leopold Center Ecology Initiative, (515) 294-5610, wink@iastate.edu

Laura Miller, Leopold Center Communications, (515) 294-5272, lwmiller@iastate.edu

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