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Abstract

Previous studies have evaluated the economics and ecosystem services of perennialbioenergy crops when replacing grain crops on marginal (environmentally critical and/or underproductive) lands. This study used life cycle analysis (LCA) to investigate the greenhousegas (GHG) emissions of perennial crops when grown in targeted landscape positions and theirimpact in reducing nitrogen leaching. Specifically, LCA was performed to evaluate the GHGemissions of growing shrub willow (SW) on marginal lands in the Indian Creek watershed, IL,U.S.A. SW was grown as a short-rotation woody crop with a 21-year rotation under three scenarios including a business-as-usual field-scale production with nitrogen fertilizer application and two un-fertilized subfield buffer scenarios (single subfield or multiple subfields) grownalongside cornfields to reduce nitrate leaching. The average annual GHG emissions from SWproduction and depot transportation were lower (0.33 0.81 Mg-CO2e/ha) than if corn were produced on the same land (1.69 1.81 Mg-CO2e/ha). Although SW is not harvested annually,these results suggest SW production can reduce agricultural landscape emissions in the long term, mirroring results of other studies. When both feedstocks were used to produce ethanol, the well-to-wheel GHG emissions of SW ethanol were 1.5 6.3 g-CO2e/MJ, compared with cornethanol at 42.9 43.5 g-CO2e/MJ, accounting for land use change. Emission results were most sensitive to the SW yield, while the percentage of avoided nitrogen to the watershed had a minor impact on the overall emission results as nitrous oxide (N2O) emissions from leached nitrogen are smaller than other N2O sources such as fertilizer production.