Kurt Thelen and Andrew Adkins, Michigan State University, East Lansing, MI
Cellulosic ethanol biofuel is a popular, renewable, liquid fuel candidate. Switchgrass is one of the most popular feedstocks for cellulosic ethanol production. One of the major components in maximizing ethanol production is maximizing feedstock harvest efficiency. Harvest efficiency is largely determined by the harvest timing and the equipment used in the harvesting process. Four harvest timings were studied: early Fall, mid Fall, late Fall, and early Spring. Two harvest methods were studied: cut-and-bale and direct chop-and-ensile. It was hypothesized that Switchgrass harvest yield would be maximized using the direct chop-and-ensile harvest method during the early Fall harvest timing. Stands of Switchgrass (10’ x 40’) were harvested according to their corresponding harvest treatments. Yields were calculated on a pounds per stand basis corrected for moisture content. Results showed that the direct chop-and-ensile method yielded significantly higher feedstock yields compared to the cut-and-bale method for all four harvest timings. No significant feedstock yield differences were found between the three Fall harvest timings for both harvest methods. However, there was a significantly lower feedstock yield for the early Spring harvest compared with all three Fall harvests for both harvest methods. All statistical analysis was calculated using SAS 9.2 (SAS, Inc.). The study concluded that Switchgrass harvest yield is maximized using the direct chop-and-ensile method.