Beltsville, Md.-Sweet potatoes grown in Maryland and Alabama yielded two to three times as much carbohydrate in ethanol production experiments than field corn grown in the same states, according to Agricultural Research Service scientists who found the same results from tropical cassava in Alabama. The ARS team said sweet potato carbohydrate yields approached the lower limits of those produced by sugarcane, the highest-yielding ethanol crop, in addition to requiring much less fertilizer and pesticides than corn. The tests, performed in the field at ARS Crop Systems and Global Change Lab here and in large soil bins at ARS National Soil Dynamics Lab in Auburn, Ala., were the first comparing the root crops to corn, and in growing all three simultaneously in two different regions of the country. For the sweet potatoes, carbohydrate production was 4.2 tons an acre in Alabama and 5.7 tons an acre in Maryland. Carbohydrate production for cassava in Alabama was 4.4 tons an acre, compared to 1.2 tons an acre in Maryland. For corn, carbohydrate production was 1.5 tons an acre in Alabama and 2.5 tons an acre in Maryland. Researchers point out that that more economical harvesting and processing would be needed if cassava and sweet potato are to become competitive with corn as ethanol sources, but they claim it would be worthwhile to start pilot programs to study growing methods.
Transparency Across the Fertilizer Value-Chain