Iowa researchers study ground cover, corn

By Kris Bevill
Web exclusive posted July 11, 2008 at 11:30 a.m. CST

Researchers at Iowa State University have been studying the possibilities of using certain types of ground cover to replace corn stover, allowing the stalks and leaves to safely be removed from fields for use in ethanol production.

The three-year research project is being paid for by the SunGrant Initiative, which receives its funding through the U.S. Department of Transportation, the U.S. DOE and the USDA.

"The issue is this – how do you harvest corn stover in a way that sustains the productivity of the environment for producing future corn?" said Ken Moore, Iowa State University agronomy professor and lead researcher for the project.

Corn stover has traditionally been left in the fields after harvest as a way to slow wind and water erosion and to re-supply the soil with organic material. Now, as ethanol producers look at corn stover as a possible feedstock for ethanol production, research is needed to determine an alternative source of ground cover and nutrient enrichment for farmers' valuable corn fields.

The most promising solution researchers have looked at so far is planting a ground cover of grasses between rows of corn that will remain in the field year-round. The "living mulch" is capable of performing all the functions that corn stover does and could possibly offer additional benefits as well. According to Moore, grasses will help keep weeds down, which will result in less need for herbicides. He added that when the grasses are combined with certain types of fungi, the number of insects will be reduced, which means less insecticide will also be used by the farmer.

Other possible benefits of this ground cover method, which have yet to be researched, include the possibility of carbon credit collection and year round benefits for wildlife. Kendall Lamkey, agronomy professor and department chair at Iowa State University, is the co-principle investigator for the project. He said the researchers haven't explored the impact living mulch could have on wildlife, but that the ground cover would certainly be similar to Conservation Reserve Program acreage.

The combination of plants is not new. In fact, Moore pointed out that nature does exactly this sort of thing all the time. "You see prairies that have these complementary mixtures of multiple species that grow and share space. In a way we are sort of simulating the grassland systems that were originally here, but in a very simple way."

"The whole point of this research is to get roots in the ground," said Lamkey, adding that the research began last fall and no conclusions have been made yet. However, he is optimistic about the study so far.

There are challenges involved in co-planting ground cover with corn. The largest obstacle to overcome is to find a way to maintain corn yields. Current research shows that corn yields are lower. Lamkey said that is because corn is not a competitive species and "doesn't like to be growing with anything else in the field." However, he is focused on finding a type of corn that will withstand competition, specifically early in the growing season when corn is at its most vulnerable stage.

Other challenges being researched include finding which types of grass will not compete with the corn and what sort of agronomic practices will work best.

"I think that by the end of the project [in 2010], I am optimistic that we'll be able to identify the one or two species of grass that we really need to work with for the living mulch," Lamkey said. "I am also fairly optimistic that we'll be able to indentify inbred corn lines that do well in these systems."