By Todd Neeley
DTN Staff Reporter
BEAVER CROSSING, Neb. (DTN) -- When it comes to biomass production for bioenergy tons per acre will be king. On one particular switchgrass test plot in southwestern Seward County in Nebraska, it's not difficult to pick out a top-of-the-heap new variety of switchgrass bred to survive harsher winter conditions in the Cornhusker state.
Here in mid-August one particular tract stands nearly 7 feet high -- bushy thick. Chances are the plot will produce 7 to 8 tons per acre without irrigation -- ideal for biofuels production, only if biorefineries were available to take deliveries from farmers. There are just a handful of biorefineries taking switchgrass, but none in Nebraska. The test plot was planted on May 10, 2013, and is almost fully established 15 months later.
A 50-million-gallon cellulosic ethanol plant would need some 625,000 tons of biomass per year within a 25-mile radius. So University of Nebraska Extension experts hosting a biomass field day near Beaver Crossing on Tuesday, said higher-yielding switchgrass grown on pivot corners likely would be the most viable route for bioenergy production in Nebraska.
Just a decade ago there were more questions than answers about whether switchgrass could be a viable crop because of the regional variation in climatic conditions. Few experts thought it possible to grow a warm-weather plant like switchgrass in a cold northern state. Kenneth Vogel, a research geneticist, began crossing two breeds of switchgrass in 2000 to produce a plant able to survive cold in the Cornhusker state.
Fifteen years after the beginning of that work a new switchgrass variety called "Liberty" is fewer than two years away from commercial release, although big questions remain about the future of advanced bioenergy production using biomass. Doubt about EPA's long-term intentions with the Renewable Fuel Standard has made it difficult for advanced biofuels companies to plan construction of new plants.
Vogel, now a research leader for USDA-Agriculture Research Service, said even though there isn't a switchgrass bioenergy market in Nebraska it can fit with the state's cattle industry. Cattle are able to graze on switchgrass, he said, and the new variety, in particular, needs to be grazed heavy enough to keep the plant in a vegetative state.
"You're going to have to manage the harvest and grazing differently," Vogel said, including pulling cattle off in the first week of September in Nebraska to maintain enough vegetation to produce during the next growing season.
Rob Mitchell, research agronomist with ARS, said, initially, when switchgrass was touted by President George W. Bush and an always-budding cellulosic ethanol industry as potentially a more sustainable biofuels feedstock to corn, the agriculture industry believed growing switchgrass would be a hands-off crop. Mitchell said research conducted at Beaver Crossing and other test plots shatters that notion.
With the potential of a commercial market in two years, extension agents have been hosting field days to show farmers the equipment needed to plant and harvest, as well as talking about potential solutions to fighting pests and disease.
"Perennial crops don't just pop up on their own," Mitchell said. It wasn't long ago that the general approach to growing perennial grasses was to put seed in the ground and wait.
"In 12 months you can get a harvestable yield," Mitchell said. "If we're doing things right it can grow rather quickly. We don't get there all the time, but it is close to 100% established."
With varieties such as Liberty the yield goal of about 10 tons is possible, he said, as it has been reached in some trials. The higher the yield, Mitchell said, the more feasible bioenergy production using switchgrass becomes.
"If you can grow dryland corn this will work here," Mitchell said.
However, switchgrass shouldn't be planted west of Cozad in western Nebraska -- or west of the 100th meridian, which essentially splits the United States in half north to south. Switchgrass should be planted two to three weeks before or after the corn-planting date. The plant performs well when planted into Roundup Ready soybeans, he said, and it is important for farmers to buy high-quality certified seed.
Without a higher-yielding switchgrass, producing enough biomass to fuel a single biorefinery would be difficult. Extension personnel talked about how growing switchgrass on pivot corners would be a feasible way of producing enough biomass to feed a biofuels plant. In Seward County, Neb., however, to produce enough biomass to fuel a 50-million-gallon biofuel plant with switchgrass grown on pivot corners would require planting on all corners of some 200,000 corn acres.
One of the major concerns for growing switchgrass as a cash crop is whether farmers can make enough money to cover inputs, even before biorefineries begin demanding switchgrass. Mitchell said farmers could expect to receive about $100 a ton from biorefineries. In addition, farmers need a market for switchgrass in order to establish the crop prior to the opening of a biomass facility.
Feeding trials have shown switchgrass can be good forage for cattle, but is deadly to horses. "The only significant market is for hay crop," he said, selling for $75 to $125 a ton.
POTENTIAL PESTS, DISEASES
Fred Baxendale, University of Nebraska extension and research entomologist, forensic science program director, said few arthropods are known to seriously damage switchgrass.
"So far we haven't identified" any problems, he said. Potential pests to switchgrass include grasshoppers, chinch bugs, armyworms, cutworms, stalk borers, switchgrass moths, aphids, gall midgets, white grubs, billbugs, wireworms and thrips.
Even if pests damage switchgrass, Baxendale said the plant compensates by producing more foliage. The switchgrass moth, he said, is a problem in South Dakota and in northern Nebraska counties.
Stephen Wegulo, University of Nebraska Extension plant pathologist, said preventing disease in switchgrass is not much different from other crops.
Farmers can manage disease by using clean seed, applying seed treatments, establishing good soil drainage and by using optimum planting depths. In particular, he said switchgrass viruses to monitor for include panicum mosaic, switchgrass mosaic, barley yellow dwarf and sugarcane mosaic. When it comes to fungi, Wegulo said switchgrass can suffer up to 40% yield losses in smut transmitted via seed.
Todd Neeley can be reached at firstname.lastname@example.org
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