Effect of dry matter loss on profitability of outdoor storage of switchgrass

The impact of storage dry matter (DM) losses on the profitability of producing switchgrass (Panicum virgatum L.) is poorly understood. This article evaluates net returns to storage considering DM losses using data from a 500-day experiment at Milan, TN. Switchgrass was harvested in large round and large rectangular bales wrapped with twine and stored outdoors with and without a tarp on grass, gravel, and pallet surfaces. Comparative breakeven analysis incorporating DM loss estimates from the experiment determined optimal harvest and storage strategies. Bale shape and choice of cover most impacted DM losses, which increased at a decreasing rate with time in storage. Even though covered rectangular bales had higher DM losses than uncovered round bales, they were more profitable for a wide range of switchgrass price and storage period combinations because of lower overall harvest, storage and transportation costs Mg−1. Uncovered round bales were only more profitable than covered rectangular bales for high price and long storage period combinations. Covered round bales were not profitable for any price and storage period combination evaluated in the analysis. The use of a cover is generally worth the added cost for rectangular bales but not for round bales.

► We model effect of dry matter loss on profitability of switchgrass stored outdoors.
► Covered and uncovered bale storage data were from a 500 day Tennessee experiment.
► Lower cost covered rectangular bales were profitable despite higher dry matter losses.
► Higher cost uncovered round bales were not profitable despite lower dry matter losses.