Research results available for five completed projects

Thursday, January 9, 2014

AMES, Iowa – What happens when you add diversity to Iowa’s conventional corn-soybean cropping system? An Iowa State University agronomist has found that you can reduce herbicide inputs, maintain and even improve weed suppression, enhance soil quality by several measures, plus boost grain yields.

Read about this research project and several others, in summaries of final reports submitted to the Leopold Center for Sustainable Agriculture. All projects were funded as part of the Center’s long-running competitive grants program. Summaries of five recently completed grant projects and links to related sources are available on the Leopold Center website at:

The cropping system research began in 2002, conducted by ISU agronomy professor Matt Liebman at the ISU Marsden Farm in Boone County. This 22-acre field experiment assesses agrichemical input use, yields, weed dynamics, economic characteristics and soil functions of diversified and simpler (two-year) crop rotation systems. The diversified corn-soybean systems are three- and four-year rotations that include perennial legume species (oats) and organic matter amendments, such as manure. In 2008, two contrasting technology packages were added to the experiment to compare transgenic and non-transgenic corn and soybean.

Since receiving a Leopold Center research grant to set up the experiment, substantial additional funds to maintain the plots have come from the USDA’s National Research Initiative and Agriculture and Food Research Initiative.

The latest round of completed projects includes a successful education and outreach program for landowners, conducted by the Drake University Agricultural Law Center. The Sustainable Agriculture Land Tenure (SALT) Initiative examined farm leases, conservation easements, estate planning and other tools that landowners can use to manage their land in a more sustainable, resilient and profitable manner. The Initiative has worked with the ISU Beginning Farmer Center, the Women, Food and Agriculture Network and Practical Farmers of Iowa to reach landowners as well as those interested in farming the land.

Recently completed projects also evaluated a decade of local food systems work in northeast Iowa and efforts to bring local food to three rural school districts in the region. Another research project found that soil in organic corn and soybean fields had a greater abundance of naturally occurring pathogens that can kill insect pests and suppress pest outbreaks than soil in conventionally managed fields.

The project titles are:

Each completed research project listed above has a multi-page summary of findings and a one-page brief that are available to download in an easy-to-read format.

Another publication shows abstracts from more than 300 projects funded by the Leopold Center from 1996 through 2013. The abstracts are listed by topic and year of completion. Get the publication, Abstracts of Recent Leopold Center Projects, by title at:



Jeri Neal, Ecology Initiative, (515) 294-5610,

Craig Chase, Marketing and Food Systems Initiative, (515) 294-7836,

Mary Adams, Policy Initiative, (515) 294-5832,

Laura Miller, Communications, (515) 294-5272,