Feed and fuel: the dual-purpose advantage of an industrial sweetpotato

BACKGROUND: Sustainable agricultural systems must support nutritional requirements, meet the energy demands of a growing population, preserve environmental resources and mitigate climate change. The sweetpotato (Ipomoea batatas L.) is a high-yielding crop that requires minimal fertilization and irrigation, and the CX-1 industrial cultivar offers superior potential for feed and fuel. RESULTS: CX-1 had the highest agronomic fresh vine yield (51.5 t ha(-1)), averaged over two cropping seasons, compared with Hernandez (33.7) and Beauregard(21.8) varieties. CX-1 vines were more nutritional than the table varieties, specifically in regard to relative feed value (205), water-soluble carbohydrates (171 g kg(-1) drymatter (DM)), total digestible nutrients (643 g kg(-1) DM), metabolizable energy (10.2MJ kg(-1) DM) and organic matter digestibility. Their lower fiber and lignin concentrations contributed to their freshness and digestibility through out maturity. Significantly higher iron concentrations make the CX-1 vines a valuable, low-fat iron supplement for animal feed. The CX-1 roots also showed the highest bioethanol potential (82.3 g ethanol kg(-1) fresh root) compared to Hernandez (64.5) and Beauregard (48.1). CONCLUSION: The CX-1 industrial sweet potato is an ideal dual-purpose crop for tropical/subtropical climates that canbe utilized as a non-grain-based feedstock for bioethanol production while contributing a valuable, high-yielding nutritional supplement for animal feed. (C) 2016 Society of Chemical Industry