Removing corn residue from fields can have a big impact on soil and water quality, according to new research from an Iowa State University agronomist.

Mahdi Al-Kaisi, an agronomy professor, is urging farmers to consider topography, tillage systems, nitrogen application and the amount of organic matter present in their soil to determine how much corn residue, or the plant material left behind after harvest, they should part with.

“Residue removal has some real environmental impacts on soil health and water quality,” Al-Kaisi said. “It needs to be approached thoughtfully and on a site-specific condition basis.”

His most recent publication, which appeared in the peer-reviewed Soil Science Society of America Journal, shows how a decrease in crop residue can lead to increases in greenhouse gas emissions from the soil.

Al-Kaisi began the study in 2008 in response to the continued development of cellulosic ethanol, a biofuel made from corn residue. One cellulosic ethanol plant is up and running in Emmetsburg, and another is under construction in Nevada.