An Analysis of Bioenergy Cropping Systems in the Great Lakes Region.

United States Energy Policy such as the Renewable Fuels Standard has been enacted to reduce our dependence on fossil fuels and mitigate global climate change. The Great Lakes BioEnergy Research Center,BioEnergy Cropping Experiment, established in 2008 at UW-Madison and MSU, contains annual cropping systems (corn, soybeans, canola) and perennial cropping systems (switchgrass, miscanthus, a native grass mix, old field, poplar, a prairie grass mix). Field inputs, gas emissions, and yields have been tracked since establishment. This field data was used to perform a life cycle assessment on these cropping systems with a focus on the global warming potential (GWP). The results of the LCA showed that the continuous corn cropping systems had the highest nitrous oxide emissions per hectare per year at both study locations as expected.  However, the corn systems were among the most favorable in terms of net GWP, due primarily to displacement of gasoline.  The perennial systems generally had a negative GWP per hectare per year due to limited inputs and low gas emissions from those systems.  Nitrous oxide emissions had the greatest effect on the GWP of each cropping system of all of the gas emissions considered.