| Abstract
| - Biobased product life cycle assessments (LCAs) havefocused largely on energy (fossil fuel) usage and greenhousegas emissions during the agriculture and productionstages. This paper compiles a more comprehensive lifecycle inventory (LCI) for use in future bioproduct LCAs thatrely on corn or soybean crops as feedstocks. Theinventory includes energy, C, N, P, major pesticides, andU.S. EPA criteria air pollutants that result from processessuch as fertilizer production, energy production, and on-farm chemical and equipment use. Agroecosystem materialflows were modeled using a combination of GREET (theGreenhouse Gases, Regulated Emissions, and Energy Usein Transportation model), a linear fractionation modelthat describes P biogeochemical cycling, and Monte CarloAnalysis. Results show that the dominant air emissionsresulted from crop farming, fertilizers, and on-farm nitrogenflows (e.g., N2O and NO). Seed production and irrigationprovided no more than 0.002% to any of the inventory emissionsor energy flows and may be neglected in future LCAs ofcorn or soybeans as feedstocks from the U.S. Corn Belt. Limecontributes significantly (17% of total emissions) to airemissions and should not be neglected in bioproduct LCAs.
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