Switching it up?

Switchgrass as an alternative crop? Not quite yet.

Cellulosic ethanol production is still in its infancy, with research increasing and only a handful of pilot plants in operation. However, biomass and cellulosic ethanol crops will drive the next wave of agricultural commodities and push producers to re-think crop selection. In time, alternative crops, such as switchgrass, could be a realistic option.

"At this time, it's grown as a cover crop on some CRP land and in some limited amount as a hay crop," says University of Nebraska-Lincoln professor Richard Perrin. "It has received attention as a potential biomass crop for the energy market, but these markets are still in the future."

Switchgrass is a warm-season perennial grass that is native to North America. Perrin says it is competitive with other grass crops in a wide variety of regions, throughout the Great Plains and the Southeast. Because of its native history, it is resistant to many pests and plant diseases and capable of producing high yields with very low applications of fertilizer.

Some fertilization may be necessary to maintain harvestable stands, says Ag Marketing Research Center specialist Dan Burden. The crop is proven to be very tolerant of poor soils, flooding and drought. Switchgrass is also a valuable soil protection cover crop - it binds loose soils and provides valuable wildlife habitat.

However, as a crop, switchgrass requires slightly uncommon management. For optimal output, it is harvested only every other year, rather than annually. Even though it's common in CRP fields, switchgrass harvested for energy generation must be a relative monoculture, meaning derived from primarily a single seed type, rather than part of a mixture of grasses. Once the grass reaches maturity in harvest years, it is swathed and baled, much like other forage crops.

Perhaps the greatest benefit of switchgrass comes to soil quality through its manipulation of nutrients. Switchgrass is a C4 grass, which means nutrients move throughout the plant during different times of the growing season. This culminates with the first killing frost in the fall when nutrients like phosphorous and potassium move into the roots. As a result, nutrients stay circulating throughout the soil, rather than being removed, like they are with traditional row crops.

"It's tricky to get the crop established, but it's very important economically to get it well established the first year. After that, it's simple," Perrin said. "It requires some special herbicides during the establishment year and apparently some skill and luck in getting the seedbed properly prepared and the seed planted at the correct depth." Perrin also says that there are several different varieties of switchgrass seed available, all of which were developed for animal forage rather than biomass usage.

While the switchgrass market itself is still emerging, Canada is ahead of the U.S. in developing switchgrass as a biofuel. Producing switchgrass pellets for use in decentralized home heating systems is well developed, and pellet stoves are selling to individual homeowners as supplemental heating sources. These are similar to the "corn stoves" that burn waste or surplus corn or wood-waste pellets sold in the United States.

Perrin and other UNL researchers analyzed the economics of switchgrass as an alternative crop in the Midwest. The study included the operations of 10 farmers who have produced 15-20 acres of switchgrass for the past five years on acreages that would qualify for CRP land. The average production cost for switchgrass came to be about $60 per acre, with an average 2.2 tons per acre yield. The better farms averaged 2.5 tons with a $47 per ton cost, and the poorer farms averaged 1.6 tons per acre with costs exceeding $80 per acre.

In addition, the cost of the switchgrass feed stock would be about 75 cents per gallon, if 80 gallons could be refined per ton of switchgrass. Compared to corn, it would be $1 per gallon, which is still competitive, even with high land costs.

However, until there are commercial plants to buy switchgrass, Perrin sees limited marketability for the crop.

"Until a market exists for biomass to be used in cellulosic ethanol production there is not really a market. Then it will be a higher price than just for hay, because the hay price itself is not sufficient to encourage much production," Perrin says. "At that point, it will be a crop that needs little attention from year to year except for one harvest operation, and it will remain in production for many, many years."

Although switchgrass is currently not an economical feed stock for ethanol production, federal mandates could soon require it to be as the nation moves towards biomass for its ethanol production. Researchers have indicated that switchgrass can be competitive as an ethanol feedstock, and the crop boasts potential. But it will most likely take several more years of research and development before becoming mainstream.

What's all the excitement?