AMES, Iowa – Organic agriculture practices eschew many synthetic fertilizers and pesticides, putting pressure on crops that conventional farming circumvents. That means an organic farmer who doesn’t use herbicides, for instance, would value crop varieties better suited to withstand weeds.
Enter Thomas Lubberstedt, a professor of agronomy at Iowa State University. Lubberstedt and a team of ISU researchers recently received a four-year, $1 million grant from the U.S. Department of Agriculture to advance organic corn varieties. By the end of the project, the team aims to have identified elite varieties that will improve the performance of corn under organic growing conditions.
“Our main goal is to figure out whether new genetic mechanisms can benefit organic field and sweet corn varieties,” Lubberstedt said. “We want to develop traits that can do well under organic conditions.”
Iowa State University agronomists and horticulturalists have joined forces to find the best relationship between row crops and perennial cover crops.
They were awarded a National Institute of Food and Agriculture grant this year as part of the agency’s effort to support research on agricultural systems and production of biomaterials and fuels. Ken Moore, David Laird, and Andy Lenssen, all professors of agronomy, and Shui-zhang Fei, associate professor of horticulture, make up the team.
Photo: Graduate student Allen Chen uses the light box he made to take photos of perennial cover crops in a test field west of Ames in September.
The team is studying turfgrass species to be used as perennial cover crops since they do well in cooler weather, Fei said. They planted several varieties of turf grasses in field trials west of Ames this fall to see which do not compete with corn production while still providing environmental benefits.
Issue: Cover crops have significant potential to improve water quality by limiting erosion when row crops are not growing, and by limiting the loss of nitrogen by leaching. Yet widespread adoption has been limited, as the yield of subsequent-year corn crops may be negatively affected by cover crops. One reason for this is the potential for immobilization of nitrogen from soil organic matter as cover crop residues decompose.
Issue: The STRIPS project (Science-based Trials of Rowcrops Integrated with Prairie Strips) conducted at Neal Smith National Wildlife Refuge near Prairie City showed integrating tallgrass prairie vegetation into row-cropped watersheds can provide water quality benefits and increase biodiversity across several taxa. Because these studies were conducted on small watersheds at one location, there is a need to evaluate the water quality benefits of prairie strips when implemented on a full-farm scale across various locations in Iowa.
Issue: Cover crops are a recognized conservation practice to reduce soil erosion, and Iowa research has shown a winter cereal rye cover crop greatly reduces nitrate loss with subsurface drainage. However, little research has evaluated the impact of cover crops on total and dissolved nitrogen (N) and phosphorus (P) loss with surface runoff.