Dual use switchgrass :

Abstract

Two studies were conducted on established switchgrass plots at Columbia and Mount Vernon, Missouri. The Columbia site was located on Mexico silt loam, and the Mount Vernon site on Viraton silt loam. The first study examined the feasibility of harvesting switchgrass for biomass and summer forage within a season. Yields and forage quality were compared between four harvest management treatments: a single post-frost harvest for biomass, a forage harvest at boot stage followed by a post-frost biomass harvest, biomass harvest at post-anthesis with summer regrowth harvested as forage, and biomass harvest at pre-anthesis with summer regrowth harvested as forage. Summer regrowth was minimal at Mount Vernon due to a fragipan and shallower rooting depth at that site. Regrowth had greater lignin content and as a result, was less digestible. The second study attempted to determine the effect of switchgrass maturity on efficiency of conversion to glucose through enzymatic hydrolysis. These maturity stages included boot stage, pre-anthesis, post-anthesis, full seed, and post-frost. Lignin was not shown to negatively affect efficiency of enzymatic hydrolysis. Rather, hemicellulose was shown to negatively impact conversion efficiency, possibly because acid pretreatment was incomplete and thus some hemicellulose remained in the digested material.