Is Energycane a Viable Bioenergy Crop in North-Central Mississippi?.

Energycane (Saccharum spp.) is an interspecific hybrid of domestic sugarcane (S. officinarum L.) and a cold hardy sugarcane relative (S. spontaneum L.).  Yields of sugarcane in Louisiana exceed 89 wet Mg ha^-1 yr^-1, making it an attractive biomass crop, but the economics of granular sugar production preclude sugarcane’s use.  Crossing sugarcane with S. spontaneum confers hybrid vigor and cold hardiness to the progeny, but also causes a corresponding increase in stalk fiber, lowering sugar content. The lower sucrose concentration makes energycane uneconomical for sugar production, but opens more northern areas for planting as a bioenergy crop.  As part of DoE’s Herbaceous Feedstocks Partnership, a number of energycane test sites were established across the South.  The Starkville, MS site is the most northern, and has served as a cold screening site for over 400 energycane genotypes.  Preliminary trials indicated potential genotypes that might survive at 33º N latitude.  Larger trials were initiated in 2008 to monitor: plant growth characteristics, crown expansion, ºBrix, and yield of five energycane genotypes.  All genotypes survived five years of testing at Starkville.   Mean biomass yield of genotypes tested ranged from 15.4 to 27.7 dry Mg ha^-1 yr^-1.  ºBrix ranged from 7.3 to 14.0.  A continued increase in yield and incremental crown expansion of the ratoon crops indicate maximum yield/unit area has not been reached. Energycane dry weight yields are lower when compared to switchgrass and giant miscanthus, also grown in the area.  Lower yield coupled with harvest of the material at 65-70% moisture make energycane production in north-central Mississippi unlikely.