Corn stover can be a sustainable feedstock — USDA study

Source: Tiffany Stecker, E&E reporter • Posted: Friday, June 13, 2014

A new study shows harvesting methods used by a planned cellulosic ethanol facility are helping keep soils healthy and prevent carbon losses.

POET-DSM Advanced Biofuels’ Project Liberty — an Emmetsburg, Iowa, refinery with an annual capacity of 25 million gallons — would make ethanol from corn stover — cobs, leaves, husks and stalks left on fields after harvests. Project Liberty is expected to open this year (Greenwire, Dec. 13, 2013).

“Successful deployment of cellulosic bioenergy production operations such as the POET-DSM ‘Project Liberty’ program … can strengthen rural economies, help ensure energy security, and reduce greenhouse gas emissions without contributing to soil degradation — another global challenge,” said Douglas Karlen, an author of the new report and a researcher with the Department of Agriculture.

POET-DSM commissioned the study by Karlen and Stuart Birrell, an associate professor of agricultural and biosystems engineering at Iowa State University. The authors plan to submit their research for publication in a peer-reviewed journal.

The paper finds that the best locations for growing corn stover include fields that are flat or with very gradual slopes of less that 3 percent grade, have consistent grain yields of 175 bushels per acre and include good nutrient management plans, in which farmers use fertilizer efficiently.

The sustainability of corn stover fuels has recently been called into question. A study out of the University of Nebraska, Lincoln, found that removing corn stover and cobs from farms could make biofuels from these materials emit more greenhouse gases than gasoline in the short term (ClimateWire, April 21).

Both industry and other scientists criticized the Nebraska study (ClimateWire, April 28).