Practices such as planting cover crops and adding manure and compost can reduce carbon loss in fields where corn stover is removed for ethanol production according to research from Michigan State University. The research programme, carried out by Michigan Agricultural Experiment Station crop and soil scientists Kurt Thelen and Doo-Hong Min and graduate student Bradley Fronning measured soil carbon changes as well as greenhouse gas emissions of nitrous oxide and methane from several test fields. They also considered the cost of carbon crops and fuel use, as well as the methane and nitrous oxides generated by manure.

"These results demonstrate that bio-energy cropping systems, particularly those integrating livestock manure into their management scheme, are a win-win option on both alternative energy and environmental fronts," Thelen said. "Under proper management, livestock manure can replace carbon lost from corn stover removal and actually provide an environmental benefit, both in terms of greenhouse gas mitigation and the improved soil properties associated with increasing (soil carbon) levels, such as increased water retention."

Research continues at MSU to evaluate the environmental, agronomic and economic sustainability of bio-energy cropping systems.

"It will be important to build on this research by comparing tillage systems — no-till versus conventional tillage — and looking at integrated cropping systems such as corn-alfalfa rotations, which in addition to their carbon storage and bio-energy value, are very important crops as feed sources for the dairy industry," Min said.

Research funding was provided by the MAES, the U.S. Department of Agriculture Cooperative State Research, Education and Extension Service, and the Consortium for Agricultural Soils Mitigation of Greenhouse Gases program. The team’s study was recently published in the Agronomy Journal and is available online at http://agron.scijournals.org/cgi/content/abstract/100/6/1703.