In southern Ohio, a variety of grasses, shrubs and trees are being grown and analyzed to see how well they can produce something that is always in high demand: energy.
For the past few years, Ohio State University researchers have been evaluating a number of so-called "bioenergy crops" for their suitability to different regions of the state, their biomass yield and their potential to become value-added crops for farmers.
"These crops can grow on marginal land and will not take away good land from food production," says Rafiq Islam, a soil, water and bioenergy specialist with Ohio State University South Centers at Piketon. "Our idea is to use degraded soils and land not suitable to grow food crops for bioenergy production."
Islam leads several bioenergy crop trials in southern Ohio, which along with the eastern part of the state, has plenty of hilly terrain and strip-mined land that could be utilized to grow these new crops. Plants being studied include switchgrass, various prairie grasses, miscanthus, hybrid willow, Sudan sorghum grass, sweet sorghum and guayule.
One of the projects, supported by grants from Mendel Biotechnology (a California-based developer of energy crops), involves the study of seven varieties of miscanthus and three varieties of switchgrass on a total of seven acres.
"Miscanthus is a warm-season grass from Asia that is getting a lot of attention across the Midwest because of its adaptability to many different soil types, low-nutrient requirements, fast-growing nature, confined growth, and lack of dispersal -- not like Johnson grass (an aggressive weed that can outcompete crops)," Islam says. "Miscanthus grows 15-20 feet tall and has a high biomass output that can be used for combustion or conversion to cellulosic ethanol or butane."
The miscanthus planted at Piketon yields 9.6 tons of biomass per acre, according to Islam.
Switchgrass, meanwhile, is a prairie grass native to North America that grows 10-12 feet tall and can also be burned to produce energy or converted to fuel, Islam said. Both miscanthus and swithgrass are propagated via rhizome division or plugs, which can make their initial establishment difficult.
But because they are perennial crops, they can produce biomass for many years before the stands need to be replanted.
Another project at OSU South Centers, funded by the U.S. Department of Energy, involves growing switchgrass and big bluestem grass on a one-acre plot of degraded land where corn and other food crops cannot grow. Researchers are applying municipal biosolids from the cities of Piketon and Chillicothe and gypsum from coal-fired power plants to the soil to increase its fertility and improve drainage, as well as to measure their impact on crop productivity.
Additionally, Piketon researchers are studying the nitrogen requirements of a mixture of prairie grasses (switchgrass, Indiangrass and others), and how many times a year the crop can be harvested depending on the amount of nitrogen applied. Fast-growing hybrid willow trees are also being researched in a half-acre plot.
"These trees are growing in waterlogged, high-clay, high-acidity and overall bad soil," Islam says. "Trees may not provide as much biomass as grasses because it takes several years to harvest them, but they can be planted in areas where nothing else will grow and they can also help improve the soil."
Taller than corn and capable of producing up to 25 tons of biomass per acre, Sudan sorghum grass has been growing at OSU South Centers for the past eight years, Islam said. A related crop, sweet sorghum, was planted for the first time in 2012 at Piketon as part of a collaborative project with the University of Nebraska.
"We can't grow sugar cane in Ohio, but sweet sorghum can produce the same amount of sugar as sugar cane and requires half the nutrients as corn," Islam says. "It is also drought resistant and produces three types of energy: sugar for ethanol or butane, cellulosic alcohol, and biomass that can be used as animal feed or pelletized for combustion."
The last bioenergy crop being investigate at Piketon is guayule, a woody shrub native to the southeastern U.S. Guayule produces hypoallergenic rubber and a hydrocarbon that can be converted into a diesel-like transportation fuel.
"Last year, we successfully managed to grow guayule for the first time outdoors in Ohio," Islam says. "This plant is very drought tolerant, but it doesn't like standing water, so we are growing it in raised beds.
"We are testing this method of growing guayule so that in the future farmers can produce this crop on the hills of southern Ohio."