Ethanol from forages

Cellulosic ethanol is being hailed as the biofuel that will cut greenhouse gas emissions by 90 percent, reduce U.S. dependence of foreign oil and won’t take prime ag land away from food production.

Yet the biofuel, made from grass, wood or other non-edible plant material, is probably five years from commercial production despite U.S. Department of Energy funding and university and private company research.

At the same time, growers are wondering where they may fit in this new market and how they can prepare for it. Pilot cellulosic ethanol facilities are being built in a number of states, including Tennessee, South Dakota, Louisiana, Kentucky and Florida.

Pilot plants are scheduled to begin production this year, starting with readily available crop residues like corn cobs and stover. But there are challenges, including finding an efficient way to convert plant materials to produce cellulosic ethanol and creating government policies that encourage biorefinery investments and growth as well as allow biomass crop production on Conservation Reserve Program land.

One piece of the cellulosic ethanol puzzle that is in place is switchgrass. Varieties bred as dedicated energy crops are now being marketed commercially. Growers in Tennessee and Kentucky are learning to raise switchgrass, deemed by the Department of Energy as a prime crop that can provide good yields with low inputs on marginal land.

“Switchgrass has a lot of things going for it; it’s got a seed that’s easy to plant,” says Ken Vogel, USDA-ARS forage breeder at the University of Nebraska-Lincoln. “It’s easy for farmers to handle and, for the first generation of energy crops, we’re furthest along on this and we’ve got the most information on it.”

The perennial warm-season grass gives high yields for 10 to 15 years. Some of Vogel’s switchgrass plots have yielded more than 10 tons per acre of the 6-foot to 8-foot tall crop. Farm fields, however, aren’t expected to yield more than 6 to 8 tons per acre, and a University of Nebraska switchgrass cost-of-production study on 10 northern Great Plains farms brought yields averaging 2 to 4 tons per acre over five years.

Switchgrass grows well in the Southeastern Coastal Plain’s sandy soils, says Jim Frederick, agronomist at the Pee Dee Research Station at Florence, S.C. He got 6 tons per acre from two harvests of a two-year switchgrass stand. It takes three years for switchgrass to produce top yields, he adds.

Other crops being researched as possible energy crops include giant miscanthus, alfalfa, sugar cane and energy cane, sorghums and other perennial grasses. For a well-rounded report on cellulosic ethanol and growing energy crops like switchgrass, watch for the March issue of Hay & Forage Grower or visit Hay & Forage under Most Recent Issue.

TAGS: Corn
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