Can grasses replace corn as ethanol crop of choice?

The problem with corn ethanol is that the biofuel's main ingredient has dual roles: as an energy source for fuel and as a food source for us.

And it certainly doesn't help that the crop is relatively costly and labor-intensive to produce.

A new study by University of Illinois researchers says grasses might be a more sustainable alternative that could give biofuels the boost they need to succeed.

Whether you believe ethanol to be a viable alternative to petroleum-based gasoline or not, the fact is that federal regulations now mandate that 79 billion liters of biofuels must be produced annually from non-corn biomass by 2022.

But corn's aforementioned dual role means that the price of fuel and food would be linked. As ethanol consumption grows, so could the price on food.

So Illinois professors Atul Jain and Madhu Khanna set out to analyze potential bioenergy crops in the American Midwest.

Their findings: large grasses, such as switchgrass and miscanthus, could do corn one better and provide biomass with the added benefits of better nitrogen fixation and carbon capture, higher ethanol volumes per acre and lower water requirements.

Switchgrass is large prairie grass native to the Midwest, and Miscanthus is a sterile hybrid grass that's already widely cultivated in Europe as a biofuel crop. Neither are used for food.

The team came to their conclusion by looking at the biophysical -- where the crops can grow, under which conditions -- and socioeconomic aspects of grasses in the region on a county-by-county basis.

They predicted local yields for the two grasses in question, and used an "integrated sciences system" model to estimate yields, carbon uptake and atmospheric effects from changes in land use.

Results were as follows:

• Yield is the most important factor to influencing land owners to use their land for bioenergy crops.
• In the Midwest, Miscanthus yields up to three times as much as the native switchgrass.
• Both grasses yield less in colder regions (Minnesota, Wisconsin) and more in warmer areas (Illinois, Missouri).
• Most notably, the southernmost areas are predicted to have greater production of grasses than of current corn and soy crops. In other words: bioenergy could be cost-effective from a farmer's point of view.

The researchers also estimated the minimum price at which landowner would need to sell the two grasses to break even on costs, then compared the cost to the return from corn and soybeans.

One snag is that unlike annual crops, miscanthus and switchgrass require a two-year stretch before harvesting. Another: the cost of harvesting is nearly one-third of the cost of producing biomass.

No farmer in the U.S. has attempted to harvest grass on such as large scale, making estimates difficult, the researchers said. (Hay and alfalfa are the closest relevant crops, but have far less -- one-sixth to one-tenth -- the yield.)

The bottom line? Grasses work where the environment favors them over corn and soybeans, the Midwest's two cash crops.

The team says it plans to explore the cost of growing the grasses on land that's not currently used for food production. Since the grasses require less water and less fertilizer than corn or soybeans, they could theoretically thrive on land that's currently unused, doing away with a crop tradeoff and diversifying a farmer's crop portfolio.

Now that's a smart idea.

The team published its results in the October issue of the journal Global Change Biology Bioenergy.

This post was originally published on Smartplanet.com