Researchers explore ground cover substitute

By Ryan C. Christiansen
If researchers can find a species of grass that will live harmoniously with corn, that grass might provide the "living mulch" they are looking for to help make corn stover a viable option for cellulosic ethanol production.

This spring, Iowa State University researchers began studying whether certain types of ground cover might be planted alongside corn so that the stalks, leaves, husks and cobs of the corn plant can be safely removed from cornfields after harvest for use as a cellulosic ethanol feedstock. Traditionally, corn stover remains in the field after harvest to arrest wind and water erosion. Before spring planting, the crop residue is cultivated back into the soil to resupply nutrients.

So far, the most promising solution appears to be planting a ground cover of grasses between corn rows. The grasses would remain in the cornfield year-round and help to keep weeds down, which means that less herbicide might be needed. Also, if the grasses can be combined with certain types of fungi, less insecticide might be needed.

The challenge is to find a way to grow grass and corn together without affecting corn yields because corn "doesn't like to be growing with anything else in the field," according to Kendall Lamkey, agronomy professor and chairman of the Department of Agronomy at the university. Corn is most vulnerable early in the growing season, he added. However, symbiotic relationships in the field are nothing new. "You see prairies that have these complementary mixtures of multiple species that grow and share space," said Ken Moore, ISU agronomy professor and lead researcher for the project. "In a way, we are sort of simulating the grassland systems that were originally here, but in a very simple way."

The research project is being funded by the Sun Grant Initiative, which receives its funding through the U.S. Department of Transportation, the U.S. DOE and the USDA. The study is scheduled to last three years.