CROP AND WEED RESPONSES TO INCREASING ATMOSPHERIC CARBON DIOXIDE
Title: Kudzu [Pueraria montana (Lour.) Merr. Var lobata]: a new source of carbohydrate for bioethanol production
Submitted to: Biomass and Bioenergy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 1, 2008
Publication Date: January 5, 2009
Citation: Sage, R.F., Coiner, H.A., Way, D.A., Runion, G.B., Prior, S.A., Torbert III, H.A., Sicher, Jr., R.C., Ziska, L.H. 2009. Kudzu [Pueraria montana (Lour.) Merr. Var lobata]: a new source of carbohydrate for bioethanol production. Biomass and Bioenergy. 33:57-61.
Interpretive Summary: Among invasive plants, kudzu, a vine species imported from Asia to control soil erosion, now occupies over 8 million acres, primarily in the southeastern United States. Kudzu is a weed, but can produce a high volume of carbohydrate. As such, it could be considered as a potential new source for biofuel. We measured the amount of kudzu in naturally-infested fields in three states, Alabama, Georgia, and Maryland. Below ground biomass in Alabama exceeded five tons per acre. Based on the yield data and carbohydrate concentration, we estimate wild kudzu in Alabama and Georgia could produce two to four tons of carbohydrate per acre. This would rival carbohydrate production from corn and sugar cane fields, but without the costs associated with planting, fertilizer and pesticides. Wild kudzu has the potential to economically supplement existing bioethanol feedstocks, which could be of local significance to the rural U.S. economies where it grows. These results will be of interest for policy makers, scientists, agronomists and stake-holders interested in the potential utilization of plant based biofuels.
We determined the amount of standing biomass of kudzu (Pueraria montana var. lobata) in naturally-infested fields in Maryland and Alabama, USA. At each site, we evaluated carbohydrate content of root, stems and leaves. For a third site from Georgia, we evaluated the carbohydrate content of roots of varying diameters. Below ground biomass in Alabama exceeded 13 tons per hectare, and contained an average of 35% fermentable carbohydrates (sucrose, glucose and starch). Roots from Georgia of all size classes contained over 60% fermentable carbohydrates. Stems were only 1-2% carbohydrates. Biomass and carbohydrate levels in roots from Maryland were low compared to plants growing in Alabama and Georgia, being on the order of 5 tons of roots per hectare with 20% nonstructural carbohydrate. Based on the yield data and carbohydrate concentration, we estimate wild kudzu stands in Alabama and Georgia could produce 5 to 10 tons of carbohydrate per hectare, which would rival carbohydrate production from corn and sugar cane fields, but without the costs associated with planting, fertilizer and pesticides. Wild kudzu thus has the potential to economically supplement existing bioethanol feedstocks, which could be of local significance to the rural economy of the southeastern USA.