Seasonal Trends in Biomass Accumulation and Nutrient Removal of Switchgrass.

Switchgrass (Panicum virgatum L.) is considered a cellulosic feedstock suitable for biofuel production because of its drought tolerance, noninvasiveness, potential for soil carbon sequestration, and high biomass yield with low input. Information is needed on seasonal trends in biomass accumulation and nutrient removal to support decision-making on timing of harvest to maximize efficiency of fertilizer nutrient use. Our aim was to characterize seasonal trends in biomass yield, moisture content, leaf-area index, light interception, gross energy density, concentrations and removal rates of nitrogen, phosphorus, and potassium, and concentrations of other minerals and total ash. Plots were established in 2008 in Fayetteville, AR with cv. Alamo in six replications. Sequentially different plots were sampled approx. monthly in 2009, and data were fitted to regressions describing the trends. Results will be reported for the first year of this 2-yr trial.