Technical Abstract: Estimating the carbon intensity of biofuel production is important in order to meet greenhouse gas (GHG) targets set by government policy. Nitrous oxide emissions are the largest source and soil carbon the largest sink of GHGs for determining the carbon intensity of biofuels during their production cycle. Changes in soil carbon and nitrous oxide emissions are affected by precipitation, soil texture, nitrogen inputs, and quantity and quality of carbon inputs. Cellulosic biomass feedstocks such as switchgrass and corn stover and an advanced bioenergy feedstock such as winter barley are all managed very differently from each other. We will explore the life cycle GHG impacts of these 3 cropping systems.