Wednesday, May 2, 2007 - 11:00 AM

Agronomics of switchgrass as a dedicated energy crop

R.B. Mitchell, Kenneth P. Vogel, M.R. Schmer, and G. Sarath. Grain, Forage, and Bioenergy Research Unit, USDA-ARS, 344 Keim Hall, UN-L East Campus, Lincoln, NE 68583-0937

Switchgrass (Panicum virgatum L.) has been proposed as a perennial dedicated energy crop. Our objective is to present the state of the art for establishing and managing switchgrass as a dedicated energy crop.  Selecting the proper cultivar for the specific plant adaptation region, purchasing quality seed, properly calibrating the drill, planting seed 10 mm deep in a firm seedbed, and applying pre-emergence herbicides to control weeds are crucial to successful switchgrass establishment.  Stands must be monitored during the seeding year to determine if plant frequency is adequate to meet production goals. Nitrogen requirement depends on the yield potential of the site, the cultivar, and the management practices being used. In the Midwest, maximum first-cut yields are attained by harvesting switchgrass when panicles are fully emerged to the post-anthesis stage. Favorable growing conditions may promote enough regrowth for a second harvest after a killing frost.  Poor storage conditions after harvest can result in 24% dry matter loss in a single year. Additional research is need on fertilizer requirements other than N, the stage of maturity at which dry matter production and biomass composition are optimized for ethanol yield, and economical storage methods to reduce losses. Cultivars developed specifically for high ethanol yields also are needed. Based on more than 15 years of bioenergy research, switchgrass is an economically viable and sustainable dedicated energy crop for the central USA east of 100o W. longitude. A basic management package has been developed for using switchgrass as a dedicated energy crop in the Midwest.