Kumar and Richardson (University of Illinois photo)
Praveen Kumar, a professor of civil and environmental engineering, and graduate student Meredith Richardson published the findings in the journal Earth's Future. "As part of a National Science Foundation project that is studying the environmental impact of agriculture in the U.S., the Illinois group introduced a comprehensive view of the agricultural system, called critical zone services, to analyze crops' impacts on the environment in monetary terms," a UI news release said.
To compare the energy efficiency and environmental impacts of corn as food vs. biofuel, the researchers inventoried the resources required for corn production and processing, then determined the economic and environmental impact of using these resources, all defined in terms of energy available and expended. They found that the net social and economic worth of food corn production in the U.S. is $1,492 per hectare (about 2.47 acres], versus a $10 per hectare loss from biofuel corn production.
"One of the key factors lies in the soil," Richardson said. The assessment considered both short- and long-term effects, like nutrients and carbon storage in the soil. "We found that most of the environmental impacts came from soil nutrient fluxes. Soil's role is often overlooked in this type of assessment, and viewing the landscape as a critical zone forces us to include that," Richardson said.
"Using corn as a fuel source seems to be an easy path to renewable energy," said Richard Yuretich, the NSF program director for Critical Zone Observatories. "However, this research shows that the environmental costs are much greater, and the benefits fewer, than using corn for food."