CenUSA perennial grass research “yields” impressive results

By Ali Lenger

Greg Brenneman speaks at the Bioenergy Field Day at Iowa State University’s Southeast Research and Demonstration Farm near Crawfordsville this past September. Photo credit: Greg Brenneman.

Is switchgrass ready for the biofuel prime time? Judging by Iowa farmers response to yield data presented at a recent CenUSA Bioenergy Field Day, it may be getting close. The field day, held September 21st at the Iowa State University Southeast Research and Demonstration Farm in Crawfordsville, Iowa featured yield data harvested from a 3-year old switchgrass stand, including the new release ‘Liberty’.

“This field day is just one part of the education process for farmers and landowners to help them understand what the possibilities are,” said Greg Brenneman, Iowa State Extension Agricultural Engineer and CenUSA Outreach and Extension Collaborator.

Yields of different varieties of switchgrass were compared along with nitrogen fertility rates. Attendees included farmers, landowners, interested individuals, and members of governmental agencies.

This year’s results met Brenneman’s expectations with an average of five to seven tons of dry matter per acre, enough to earn switchgrass a place in the biofuel market. ‘Liberty’ switchgrass had a slightly higher yield than the rest.

“These perennial grass crops are being looked at as a form of energy that can be used anywhere,” said Brenneman. As a bioenergy crop, switchgrass has flexibility and can be refined into liquid transportation fuels or used as a feedstock for other bioproducts, including renewable “green” plastics.

University of Iowa is co-firing biomass including oat hulls, switchgrass and miscanthus with coal at their power plant along the Iowa River in Iowa City. Photo credit: University of Iowa 

In addition, both switchgrass and miscanthus, a high-yielding bioenergy grass native to Asia but now grown in the central US, can be co-fired with coal, potentially reducing the carbon footprint of electrical generation. It has been reported that both crops are being harvested from the CenUSA plots and used to power the University of Iowa’s Power Plant in Iowa City, Iowa.

Brenneman said that during the field day, the audience was genuinely interested in the switchgrass yield results. Most questions revolved around establishment, weed control, economics, and how long the stands might last.

“We’re looking at getting the public educated about bioenergy crops, so as things change and economics become more viable,” said Brenneman. “People will be ready to start growing these crops.”