Ethanol and biodiesel are the most common biofuels. In the United States, the main biofuel crops are corn for ethanol and soybean for biodiesel. Recently, cellulosic biomass, such as switchgrass, alfalfa, reed canary grass and hybrid poplar, have been proposed as “future dedicated energy crops”. Some of these crops were analyzed by researchers from the Colorado State University, Natural Resource Ecology Laboratory and the U.S. Department of Agricujlture (USDA), Agricultural Research Service (ARS) for their capacity to reduce greenhouse gas (GHG) emissions. Using life cycle analysis and the DAYCENT Biogeochemistry model, they found that cellulosic biomass feedstocks (switchgrass and hybrid poplar) can reduce GHG emissions by about 115%. Non-cellulosic biomass (corn ethanol and soybean biodiesel) could do the same by only 40%. Reed canary grass can reduce GHG emissions by 85%. Although GHG-emitting fossil-fuel-inputs are inevitable in biofuel production, bioenergy crops have the ability to offset this by absorbing CO2 greenhouse gases while they are grown in plantations. Stephen Grosso, USDA scientist, mentions that the evaluation highlights the need to improve large scale biomass-to-energy conversions and to exploit more fully agricultural co-products..