Sunn hemp: higher than switchgrass, alfalfa?

In South Carolina, scientists at the U.S. Department of Agriculture (USDA) have found that farmers in the Southeast could produce the tropical legume sunn hemp (Crotalaria juncea) and integrate it into their crop rotations by harvesting the fast-growing annual for biofuel. The study was conducted by Agricultural Research Service (ARS) scientists in Florence, SC, and supports the USDA priority of finding new sources of bioenergy.

The scientists measured potential energy production of feedstocks via direct combustion to calculate the feedstocks’ higher heating value (HHV), which indicates how much energy is released via combustion. The HHV for sunn hemp biomass exceeded the HHV for switchgrass, bermudagrass, reed canarygrass and alfalfa. Although reduced rainfall resulted in lower hemp biomass yields in 2006, sunn hemp’s HHV for both study years was 4 to 5 percent greater than the HHV of cowpeas.