Harvest Date and Storage Effects On Switchgrass Ethanol Yield and Feedstock Quality.

Biorefineries must know how harvest date, storage method and duration of storage interact to influence switchgrass ethanol yield and feedstock quality. Our objective was to compare the effect of harvest date and storage practices on switchgrass feedstock quality. A 23-ha field of ‘Shawnee’ switchgrass was seeded near Mead, NE in 2006 and harvested with commercial haying equipment at anthesis (1 August) and 2-weeks after the first killing frost in 2007 and 2008. Switchgrass was baled in large round bales (net-wrapped 3 times and net-wrapped 4 times) and large square bales and stored (open, covered, or in a hay barn). Bales from each harvest and baling method were weighed and sampled at harvest and at 4-month intervals for 12 months and the effects of storage on feedstock quality was determined. Average yield for the seeding year and two production years was 9 Mg ha^-1. Preliminary data indicate significant differences in feedstock quality if bales are not protected during storage. Changes in switchgrass ethanol yield and feedstock quality during storage will provide valuable information to the biorefinery market.