"One reason why miscanthus yields more biomass than corn is that it produces green leaves about six weeks earlier in the growing season," Long said.

Miscanthus also stays green until late October in Illinois, while corn leaves wither at the end of August, he said.

The growing season for switchgrass is comparable to miscanthus, but it is not nearly as efficient at converting sunlight to biomass as miscanthus, Frank Dohleman, a graduate student and co-author on the study, found.

Field trials also showed that miscanthus is tolerant of poor soil quality, Long said.

Because miscanthus is a perennial grass, it also accumulates much more carbon in the soil than an annual crop such as corn or soybeans, he added.

Using miscanthus in an agricultural setting has not been without its challenges, Long said.

Because it is a sterile hybrid, it must be propagated by planting underground stems called rhizomes.

This was initially a laborious process, Long said, but mechanization allows the team to plant about 15 acres a day.

In Europe, where miscanthus has been grown for more than a decade, patented farm equipment can plant about 50 acres of miscanthus rhizomes a day, he said.

Once established, miscanthus returns annually without needing to be replanted.

If harvested in December or January, after nutrients have returned to the soil, it requires little fertilizer.

Mustard family

With funding from the US Department of Agriculture's Cooperative State Research, Education & Extension Service (CSREES), a research group in Texas, Arizona and Illinois is looking at lesquerella, a member of the mustard family, as a potential source for energy.

Lesquerella (Lesquerella fendleri) grows naturally in arid and semi-arid landscapes and is native to areas in the southwestern US and Mexico.

The plant produces seeds that are slightly smaller than alfalfa but that hold a powerful resource: a unique vegetable oil rich in hydroxy fatty acids.

Lesquerella has several novel properties. The oil contains natural, unique molecules (estolides) that are rare in other oilseeds.

These molecules promote natural ease of flow of the oil under many different conditions. Naturally occurring estolides allow lesquerella oil to flow more easily at cold temperatures than petroleum.

Camelina is also gaining attraction as a viable option. Camelina, an oilseed crop also in the same family as mustard, is currently being grown throughout the US and Canada and crushed to produce biodiesel by Great Plains-The Camelina Co.

Camelina does not take away from land currently being utilized for food production because it has the ability to grow on marginal land utilizing very little moisture.

It also fits into many farming operations as an excellent rotational crop to break the cycle of continuous small-grain cropping.

Even more important to some growers, camelina has been shown to enhance the yield of subsequent crops like wheat by up to 15pc.

Ted Durfey, president of Natural Selection Farms Inc. in Washington, is one of the crushing partners working with Great Plains.

"My main reasons for getting involved are to create greater sustainability through local production of livestock meal and oil for biodiesel and reducing dependence on foreign oil," Durfey said. "Camelina fits nicely in low-rainfall regions of our state and creates an additional low-input rotational crop, which aids in the reduction of weed and disease cycles."