Sweet Potato and Cassava Have Higher Yields of Ethanol than Maize

Scientists studying sweet potato starch yields in Maryland and Alabama, and cassava starch yields in Alabama, discovered that these crops yielded significantly more starch for conversion to ethanol than maize.

In experiments, sweet potatoes grown in Maryland and Alabama yielded two to three times as much carbohydrate for fuel ethanol production as field corn grown in those states, Agricultural Research Service (ARS) scientists report. The same was true of tropical cassava in Alabama.

The sweet potato carbohydrate yields approached the lower limits of those produced by sugarcane, the highest-yielding ethanol crop. Another advantage for sweet potatoes and cassava is that they require much less fertilizer and pesticide than corn.

...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. _USDA_via_GCC

In order to compete with maize ethanol, less labour-intensive methods of planting and harvesting will need to be devised. Automating those processes--preferably using solar powered machinery--should make a significant difference in North American ethanol production.

The same authors claim that kudzu can offer yields comparable to maize and cane. We'll see. H/T Greencarcongress.com