Research on switchgrass isn't confined to its biofuel potential; scientists and growers are finding multiple uses for the perennial.
Growing switchgrass for biofuels on East Tennessee’s hilly ground excites a lot of farmers. With a switchgrass-based cellulosic ethanol pilot plant at Vonore, that makes sense.
But farmers and researchers are finding that switchgrass can be a good hay crop as well as a cellulosic feedstock for the Vonore facility, a joint project of the University of Tennessee (UT) for-profit spinoff called Genera Energy and DuPont Cellulosic Ethanol.
“It has similar quality to fescue and orchardgrass that are cut at the best time,” says Pat Keyser, director of the UT Center for Native Grasslands Management.
“Plus, it has a big advantage over fescue because it has no endophyte fungus, which makes a 30% difference in pregnancy rates of cows. From a hay-feeding standpoint, switchgrass is preferable to fescue.”
Grazing switchgrassworks as well, notes Kim Black, who, with her husband, Brad, owns Color Wheel Farm near Vonore.
“Since switchgrass stubble is pretty tough stuff, we were concerned that the crown might be hard on cattle hooves. But we’ve learned that you need to cut above the growing point 6-8” off the ground. We’re definitely going to use it as a forage crop on our highly erodible fields,” she says.
The Blacks planted 291 acres of switchgrass as part of a UT Biofuels Initiative program that encouraged 61 area farmers to grow 5,100 acres of the crop. That was enough to supply the 250,000-gallon annual capacity pilot biorefinery, says Ken Goddard, a Tennessee Extension specialist focusing on switchgrass.
“Now we know we can grow it,” says Black. “Establishing it is kind of a pain. But once it’s established, it’s very user-friendly. We put no chemicals on it and only a minimal amount of fertilizer. Its time frame suits us, running November through January when there aren’t a lot of other things going on here.
“We’d been looking for a rotational crop to give our row-crop land a rest, and this kind of fell into our lap with the pilot plant being close to us. We said a prayer and decided to try it. Since we started in 2008, it has had its moments that were a little tricky, but for the most part we’ve enjoyed it.”
Most of the university’s contract growers have had similar experiences with switchgrass, says Kelly Tiller, Genera Energy president and CEO, who is also a UT ag economist.
“We are very optimistic that dual use as forage and hay along with cellulosic ethanol can be a great opportunity for farmers,” Tiller says. “One dairy got four forage cuttings from it this year and still cut it for feedstock. They’re in love with switchgrass just for the forage value.”
Jeff Wolfe, who grows 116 acres of switchgrass near Etowah, TN, thinks it has great potential.
“From the farmer’s standpoint, it’s a wonderful way to diversify the farm. It’s a good, profitable crop for us here. It’s renewable; it doesn’t take anything off the consumer’s dinner table.” Wolfe hopes that the biorefinery will go commercial.
Growing switchgrass for forage requires a mental shift for most farmers, Keyser says.
“It’s a warm-season grass. Fescue is a cool-season grass. Switchgrass requires more management because of its tall growth habit, but it can be managed with conventional equipment. Late May is probably the best time to cut it for hay in this area. It is better to cut it high to avoid tire damage on equipment.”
The crop’s downside? It can be finicky to establish and seedling vigor is an issue, he points out.
“Plant breeders are working to improve switchgrass genetics. They want to increase total yield. They also want to increase cellulose and reduce lignin content (to make it easier to convert the crop to biofuel). Some people think value-added products can be created out of the lignin. Like most things done on the farm, timing is the key with switchgrass,” Keyser adds.
Whether DuPont Cellulosic Ethanol will build a commercial-scale biorefinery in East Tennessee remains unknown. The company originally said it would announce plans before the end of 2011 but backed off that timeline. UT researchers involved in the project, however, remain confident it will get built. Even if it doesn’t, farmers now understand the potential of switchgrass as forage.