Biomass and Energy Yields of Energycane and Giant Reed Grown On Sandy Soils in Florida.

The development of carbon-neutral energy sources has become one of the primary challenges of the twenty-first century. Perennial grasses such as energycane (crosses of commercial sugarcane (Saccharum spp.) with S. spontaneum) and giant reed (Arundo donax L.), have been proposed as feedstocks for lignocellulosic ethanol or direct combustion. The objectives of this study were to evaluate biomass yields and fiber concentration (cellulose, hemicellulose, and lignin) of energycane genotypes and giant reed in low input rainfed sandy soils of south Florida. Eight energycane genotypes (875-3, US74-1010, US78-1011, US78-1013, US78-1014, US82-1655, US84-1047, US84-1066) and giant reed were compared in a randomized complete block design at two sandy soil locations in south Florida (Tecan, Florida Crystals Corporation, and Townsite, United States Sugar Corporation) from 2008 to 2010.  At Tecan, fresh weight yields of all energycane genotypes ranged from 53.9 to 69.3 t ha^-1 in plant cane and 44.1 to 56.7 t ha^-1 in first ratoon.  Giant reed fresh yields were significantly lower at 9.6 to 10.7 t ha^-1 at Tecan, however hemicellulose (34.0 g.kg^-1) and lignin (9.8 g.kg^-1) concentration of giant reed was greater than the energycane (27.5 - 31.9 g.kg^-1 and 5.9 - 7.4 g.kg^-1, respectively). Percent cellulose was similar across species at approximately 37%.  Overall plant cane yields were lower and first ratoon yields were higher at Townsite than Tecan, but the same yield and fiber concentration differences between energycane genotypes and giant reed were observed. Our results indicate that energycane is a more appropriate bioenergy feedstock choice than giant reed for sandy soils of south Florida.