Path Forward for Biofuels is Shorter with Miscanthus
Emily A. Heaton, Frank G. Dohleman and Stephen P. Long
Crop Sciences & Plant Biology, University of Illinois at Urbana-Champaign
The 2006 State of the Union address outlined a major initiative on cellulosic ethanol production from agricultural residues, wood chips and switchgrass (Panicum virgatum) to replace 30% of petroleum use by 2030. Achieving 30% is projected to require 1 billion dry tons of biomass each year and the dedication of 55 million acres to switchgrass, an area roughly the size currently planted to wheat in the US, plus a 60% increase in switchgrass yields by 2030. Both the area and yield increase may be significant barriers. Realization and economic viability would be achieved sooner if a more productive plant of the same form and with similarly few energy inputs for its cultivation were identified. Miscanthus x giganteus is a sterile hybrid grass of similar growth form and requirements that has been widely tested in Europe. Is it better than switchgrass in Illinois? In June, 2002 trials of Miscanthus and switchgrass cv. Cave-In-Rock were established with 4 plots of each species, side-by-side in a completely randomized design at Dixon Springs, Urbana and DeKalb. Herbicides and a single minimal application of 15 kg [Nitrogen] ha-1 were added to aid establishment. After this the only energy expended on the crops was in harvest. Previous trials of both crops suggest that annual biomass yields increase over the first two years, reaching a maximum in the third year that may maintained for several years thereafter. Yields reported here are for years 3 and 4; the 2004 and 2005 seasons.
Yields in Dry Metric Tons Per Acre
Miscanthus consistently produced more than fours times the biomass of Switchgrass at all sites in both years. Our results indicate that because Miscanthus is so high yielding it could be used to quickly achieve today the energy targets proposed by the President for 2030, and require less land to do so. A tour to the Miscanthus plots on the South Farms will be available at the conclusion of Agronomy Day.
Heaton, E., Voigt T, Long SP (2004) A quantitative review comparing the yields of two candidate C4 perennial biomass crops in relation to nitrogen, temperature and water Biomass and Bioenergy 27, 21-30.