Cell Wall Characterization Methods for Use in Bioenergy Sorghum Cropping Systems.

Comparison of Three Biomass Characterization Methods for Bioenergy Sorghum

P. T. Graham, J. P. Wight, L Hoffman Jr, J. L. Foster, C. A. Masiello, W. L. Rooney, and F. M. Hons,

Abstract: The Energy Independence and Security Act of 2007 mandates that renewable fuel production increases from 34 billion l yr^-1 to 136 billion l yr^-1 by 2022.  High biomass photoperiod-sensitive sorghum (bioenergy sorghum) [Sorghum bicolor (L.) Moench.] has shown promise for use as a biofuel feedstock in response to this demand.  The cell wall characteristics of herbage mass are important for plant residue decomposition and biofuel conversion processes.  Cell wall characterization can be performed through a variety of methods, including near-infrared (NIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, or Van Soest's detergent fiber analysis.  The goal of this research was to evaluate and compare cell wall components measured with these three methods across eighteen bioenergy sorghum production treatments.  Eighty-eight samples were taken from an ongoing study near College Station, Texas.  Sorghum was produced under the following factorial treatments: tillage (conventional and ridge-till), rotation (continuous biomass sorghum and biannual rotation with corn [Zea mays L.]), biomass return (0, 25, and 50% of the sorghum biomass or all corn stover returned), mineral return (100% of plant content returned) and N rate (0, 84, 168, 252, 280, or 336 kg ha^-1.).  We will evaluate these three cell wall characterization methods across a range of treatments, allowing their accuracy and precision to be better elucidated.  This should allow the role that cropping system management plays in influencing the cell wall characteristics of bioenergy sorghum as a biofuel feedstock to be discussed.