Biomass loss and composition change of energycane and biomass sorghum during aerobic and anaerobic storage

Energycane and biomass sorghum are two of the most promising cellulosic energy crops in the southeastern US. This study aims to determine the biomass loss and composition change of energycane and biomass sorghum in storage under different environments. Aerobic and anaerobic storage trials were conducted in seven locations across the southeastern US for energycane and six locations for biomass sorghum for 3, 6 and 9 months. Results revealed that crop type accounted for less than 3% of the variability in moisture content and biomass loss, suggesting similar storage characteristics between energycane and biomass sorghum. Average moisture content decreased from 60.7 to 50.4% after 9 months in covered aerobic storage piles but increased from 62.9 to 67.2% for anaerobic storage in anaerobic silage bags. Dry matter loss averaged 49.9% after 9 months of aerobic storage and 40.3% for anaerobic storage. Dry matter loss was described as a non-linear function of storage duration and average storage moisture, with greater loss for longer duration and higher storage moisture. Average changes in biomass composition for cellulose, hemicellulose, lignin, and ash were all less than 3% during the 9-month storage regardless of storage types. Results from this study provide valuable insights on changes in biomass quantity and quality during storage and fill a critical knowledge gap in addressing the challenge of year-round biomass supply to biorefineries.