Effect of nitrogen fertilization timing on juice and bagasse quality of sweet sorghum for biofuel production

Sweet sorghum biomass yields vary with hybrid, however, there is limited research done on how varying levels of nitrogen interacts with hybrids in affecting biomass produced and quality of extracted juice. The objective is to determine the forage and ethanol yield and quality under different Nitrogen management conditions. A three year experiment was initiated at Dupy farm, Gene Autry, OK in 2008. The treatments are two varieties (Topper and M81E) and seven nitrogen rates arranged in a RCBD with three replications. Sweet sorghum was harvested at soft dough stage and evaluated for total biomass yield, juice yield, forage quality at the time of harvest and quality of bagasse. Forage yields ranged from 60.5 to 94.9 tonne /ha and 75.5 to 98.2 tonne /ha in 2008 and 2009, respectively. Juice yields ranged from 7481 to 12626 litres /ha and 8587 to 13368 litres/ha in 2008 and 2009, respectively. There were no significant quality differences among nitrogen rates. The bagasse has 69, 3.9, 39.2, 66.3, 58.4 and 69, 4.7, 37.5 62.2, 59.6 % moisture, % Crude protein, ADF, NDF and TDN in M81E and Topper respectively. There was a positive response to fertilizer rates in 2008 and no significant difference in 2009.