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United States Department of Agriculture

Agricultural Research Service

Research Project: ENHANCED MODELS AND CONSERVATION PRACTICES FOR WATERSHED RESOURCE MANAGEMENT AND ASSESSMENT

Location: Grassland, Soil and Water Research Laboratory

Title: Soil and variety effects on the energy and carbon balances of switchgrass-derived ethanol

Authors
item Woli, Prem -
item Paz, Joel -
item Lang, David -
item Baldwin, Brian -
item Kiniry, James

Submitted to: Journal of Sustainable Bioenergy Systems (JSBS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 10, 2012
Publication Date: December 13, 2012
Citation: Woli, P., Paz, J.O., Lang, D.J., Baldwin, B.S., Kiniry, J.R. 2012. Soil and variety effects on the energy and carbon balances of switchgrass-derived ethanol. Journal of Sustainable Bioenergy Systems (JSBS). 2(4):65-74.

Interpretive Summary: In this study we examined the effects of soil and switchgrass variety on how sustainable and environmentally friendly switchgrass-based ethanol production can be. Using the Agricultural Land Management Alternatives with Numerical Assessment Criteria (ALMANAC) computer simulation model, switchgrass production was simulated for several soils and varieties. The yields were fed to the Integrated Biomass Supply Analysis and Logistics (IBSAL) model to compute energy use and carbon emissions in the biomass supply chain, which then were used to compute how much energy is produced and how soil carbon is affected. Values of these indicators increased in the direction of heavier to lighter soils and on the order of north-upland, south-upland, north-lowland, and south-lowland varieties. The values increased in the direction of dry to wet year. Differences among varieties were smaller in a dry year than in a wet year. From south to north, both indicators decreased for lowland varieties but increased for upland ones. Thus, the differences among the varieties decreased in the direction of lower to higher latitudes. The study demonstrated that the sustainability and eco-friendliness of switchgrass-based ethanol production could be increased with alternative soil and switchgrass variety options.

Technical Abstract: This study examined the effects of soil and switchgrass variety on sustainability and eco-friendliness of switchgrass-based ethanol production. Using the Agricultural Land Management Alternatives with Numerical Assessment Criteria (ALMANAC) model, switchgrass biomass yields were simulated for several scenarios of soils and varieties. The yields were fed to the Integrated Biomass Supply Analysis and Logistics (IBSAL) model to compute energy use and carbon emissions in the biomass supply chain, which then were used to compute net energy value (NEV) and carbon credit balance (CCB), the indicators of sustainability and eco-friendliness, respectively. The results showed that the values of these indicators increased in the direction of heavier to lighter soils and on the order of north-upland, south-upland, north-lowland, and south-lowland varieties. The values of NEV and CCB increased in the direction of dry to wet year. Gaps among the varieties were smaller in a dry year than in a wet year. From south to north, NEV and CCB decreased for lowland varieties but increased for upland ones. Thus, the differences among the varieties decreased in the direction of lower to higher latitudes. The study demonstrated that the sustainability and eco-friendliness of switchgrass-based ethanol production could be increased with alternative soil and variety options.

Last Modified: 10/24/2014