Sorghum: A Potential Forage and Bioenergy Crop in North Dakota.

Sorghum (Sorghum spp.) is an excellent candidate for cellulosic ethanol production since it is energy efficient, has the ability to produce high yield under droughty conditions, and has low input costs.  The objective of this study was to determine the potential forage and biomass production and quality of BMR (brown-mid rib) and non-BMR sorghums in North Dakota. Twenty two genotypes of sorghums including forage sorghum, sudangrass, sorghum x sudangrass hybrids, BMR hybrids, and sweet sorghum were seeded at Fargo and Prosper, ND in 2009. The experimental design was a randomized complete block with three replicates. Experimental units had 6 rows 0.3 m apart and 7.5 m long.  To evaluate forage yield two cuts were conducted one when the crop reached 1.35 m tall and the next right before the killing frost in the fall. To evaluate its bioenergy crop potential only one harvest was taken on 23 and 29 September in Fargo and Prosper, respectively.  The total forage yield including both harvests fluctuated between 4 and 7.8 Mg ha^-1 at Fargo and 6.9 and 11.2 Mg ha^-1 at Prosper, ND.  Sorghums are an excellent alternative as supplemental forage in the month of August when other forages reduced growth and productivity.  When harvested only once in the fall, biomass yield fluctuated between 12.1 and 20.4 Mg ha^-1 at Prosper, ND and 7.6 and 12.5 Mg ha^-1 at Fargo, ND. The highest biomass yield were for sudangrass x sorghum hybrids.  In general, the BMR character decreased biomass yield compared to same genotype without the BMR character. Estimated ethanol yield fluctuated between 1531 to 2991 L ethanol ha^-1 for non-BMR sorghums and between 1455 to 3286 L ethanol ha^-1 for BMR sorghums using conversion factors of 98 and 113 mg ethanol g^-1 of dry biomass for non-BMR and BMR genotypes, respectively.