Remember how ethanol produced from corn was supposed to help solve our energy needs and environmental issues by reducing dependence on foreign oil and producing fewer air pollutants? Well, a pair of University of Illinois at Urbana-Champaign scientists say think again.

In a study published Tuesday in the American Geophysical Union journal Earth’s Future, Praveen Kumar and Meredith Richardson say let’s go back to thinking of corn as food.

The study is part of a National Science Foundation project on the environmental effects of agriculture in the United States and an effort to determine whether the benefits of using corn as a biofuel outweigh the costs and was conducted as part of the NSF’s Intensively Managed Landscapes Critical Zone.

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“The benefit of [corn used for] feed/food is over 10 times that of biofuel,” the researchers said.

“When comparing the energy, our results indicate that corn used for ethanol has both lower energy production yields and overall net energies than corn used for livestock feed and other food products in Illinois and across the U.S. on average.”

More than 15 million gallons of ethanol was produced in the United States last year, more than total production in the rest of the world. Brazil was the second highest ethanol producer at less than 7.3 million gallons.

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"The human energy and resource input involved in agriculture production alters the composition of this critical zone, which we were able to convert into a social cost," Kumar said in a press release. The analysis focused on the layer of landscape stretching from the tree canopy to the groundwater.

Critical zone program director Richard Yuretich said the environmental costs of using corn for biofuel is much greater than using it for food.

The researchers cataloged the required resources for producing corn and then analyzed the environmental and economic effects to determine cost effectiveness and impact on atmosphere and water quality.

"One of the key factors lies in the soil," Richardson said. "We found that most of the environmental effects came from soil nutrients. Soil's role is often overlooked in this type of assessment, and viewing the landscape as a critical zone forces us to include that."

Ethanol is produced through fermentation of such raw materials as sugar cane, sugar beets or molasses, which are then mixed with a starch like corn, wheat or other grains, or cellulose.

Most U.S. ethanol plants are in the Midwest but the highest gasoline consumption is along the East and West coasts. Ethanol is generally transported by truck or barge before being blended with gasoline and other additives. Because of ethanol’s solvent properties, dedicated pipelines would have to be used to cut the transportation costs.

Generally, ethanol-blended gasoline is no more than 15 percent ethanol, but a gallon of ethanol contains less energy than a gallon of gasoline, resulting in lower fuel economy.

Ethanol became a political issue during the presidential campaign, with some candidate promoting a continuation of subsidies for ethanol production and others opposing such subsidies. The industry provided 86,000 direct jobs in the U.S. in 2015, the Renewable Fuels Association reported, adding $44 billion to the gross domestic product and $24 billion to household income.

Even though ethanol reduces the amount of carbon dioxide released into the atmosphere by motor vehicles, that reduction is offset by the amount of carbon dioxide released in growing the crops needed to produce it, as well as the production process.

The Alternative Fuels Data Center estimates corn-based ethanol reduces greenhouse gas emissions by an average of 40 percent while using cellulose-based ethanol reduces emissions as much as 108 percent compared to straight gasoline and diesel production and use.