Researchers Evaluating Switchgrass Production in Ohio

May 31, 2007

COLUMBUS, Ohio -- With double the biomass output compared to corn and low management inputs, switchgrass is shaping up to be a viable alternative crop for biofuels production. But is it an option for Ohio farmers?

Based on what Ohio State University soil scientists have seen in three years of switchgrass research, production is feasible. But it will be at least another year before the crop is harvested and data generated to evaluate the crop's production and economic efficiencies.

"We have been able to grow very good stands of switchgrass at three Ohio sites: Jackson and Western agricultural research stations, and the OARDC Hoytville branch," said Rattan Lal, an internationally known School of Environment and Natural Resources soil scientist and director of the Ohio Agricultural Research and Development Center (OARDC) Carbon Management and Sequestration Center. "The goal is to see how much biomass switchgrass grown in Ohio can produce and what impact the crop has on soil properties and soil carbon sequestration."

Switchgrass is a native, warm-season summer perennial that is often considered a good candidate for ethanol production. It can produce up to 8 to 10 tons per acre of biomass, potentially producing 1,000 gallons of ethanol per acre, compared to 400 gallons for corn. Switchgrass has lower management inputs compared to corn because of its resistance to a wide variety of insects and diseases. The grass is also tolerant of poor soils, flooding and drought.

In addition, the roots of switchgrass are efficient carbon storehouses, maintaining soil quality even after the plant has been harvested. This characteristic is attractive to Lal, who is encouraging farmers to use other alternatives than corn residue for ethanol production.

"Crop residue, corn for example, is being targeted as a source for ethanol production. From a carbon sequestration standpoint, this has serious implications," said Lal.

Carbon sequestration, also known as carbon farming, refers to the storing of atmospheric carbon in plants and soil so that the buildup of carbon dioxide in the atmosphere will reduce or slow. Lal has been leading efforts to encourage farmers throughout the world to practice carbon sequestration through no-till production.

"According to (President) Bush, by 2017, 20 percent of gas will be replaced by ethanol," said Lal. "To achieve that, we have to produce 6.5 billion gallons of ethanol and that will require 1 billion tons of residue. Of that number, 300 million tons will come from corn, and if we want to maintain carbon in the soil, we just can't do that."

Corn residue, said Lal, is not a waste but a precious commodity.

"It controls erosion; it takes four to six tons per hectare (roughly 2.4 acres) to stop run-off. It provides food for microorganisms, which keep the soil thriving. Without them, there would be no living soil. Residue denatures pollutants, which is necessary for water quality," said Lal. "Residue for the soil, grain for the people -- it's an equity we must maintain."

Lal hopes that the results of the switchgrass research will open new opportunities for Ohio farmers interested in growing crops for ethanol production. But there are some production challenges.

"Switchgrass is difficult to establish," said Lal. "Our initial establishment was not easy and we even had to do some re-planting and transferring from greenhouses. At the onset, the plant does require some babysitting."

Lal attributes the slow establishment to the plant's small seed, which also gives presents problems with weed competition.

"Once switchgrass is established, however, it's a remarkable species, growing quite successfully, especially in no-till systems," said Lal. "It also grows well on sloping land and other land areas that may not be suited for field crop production."

Switchgrass reaches full yield only in the third year after planting. When managed for energy production it can be cut once or twice a year with regular hay or silage equipment.

Lal is also participating in a multi-state research effort to evaluate the impacts of switchgrass on soil properties. Called Carbon Sequestration in Terrestrial Ecosystems (CSiTE), the project is funded by the U.S. Department of Energy. Ohio is part of the project.

Author(s): 
Candace Pollock
Source(s): 
Rattan Lal