The buzz about crop residue is increasing after the U.S. Department of Energy's Office of Biomass Program’s announcement to increase the use of crop residue as a source of biomass for renewable fuel production.

“Crop residue can be fermented, burned, charred, or gasified to produce energy,” said Fabián Fernández, University of Illinois Extension specialist in soil fertility and plant nutrition. “However the residue is used, one thing is certain — it needs to be taken out of the field.”

Fernández said it’s difficult to determine the amount of corn stover (all above-ground corn plant material except grain) that can be removed without adverse consequences to the soil's level of organic matter, or physical and chemical properties, and to successive crop yields. Because the effect of residue removal is not apparent in the short-term, multiple variables can impact results. Tillage, crop rotation and yield level are factors that will dictate how much crop residue can be harvested and still ensure sustainability of the system.

“Removing grain means removing nutrients from the soil,” Fernández said. “The export of plant nutrients from a field when crop residue is being removed is also an important point to consider.”