Submitted to: Proceedings of Forage and Grassland Conference
Publication Type: Proceedings
Publication Acceptance Date: November 22, 2006
Publication Date: December 11, 2006
Citation: Fransen, S., Collins, H.P., Boydston, R.A. 2006. Perennial Warm-Season Grasses for Biofuels. Proceedings of Forage and Grassland Conference. Reno, NV. PP 147-153. Technical Abstract: Switchgrass (Panicum virgatum) has been grown as a seed crop in the Pacific Northwest (PNW) for more than 20 years but monitoring for adaptability as forage or research into biomass for ethanol production had been lacking until about five years ago. During the past five years we have established eight field research studies at Paterson, WA (Quincy sand with 0.4% OM; 92% sand, 5.6% silt and 2.7% clay irrigated soil) and Prosser, WA (Warden silt loam 1.5 to 2.5% OM; 2-5% slope irrigated soil) evaluating switchgrass production potentials in the PNW. Stands of the Alamo variety are poor with an open canopy allowing for greater weed invasion than any other variety in our research. Kanlow, a lowland variety, has performed very well at both locations with yields after three years averaging 8.4 dry tons per acre. Dacotah is the earliest maturing and may be too early for biofuel production in the lower Columbia Basin region. We believe Dacotah maybe best adapted to a higher elevation, shorter growing season where natural precipitation is adequate for this deeply rooted plant to survive. Other varieties evaluated include Cave-In-Rock, Trailblazer, Blackwell, Nebraska 28, Sunburst, Forestburg and Shawnee. Over fertilization of switchgrass stimulates weed growth where the grass produces well with minimum level of soil nutrition. For biofuel production we harvest 2 times per growing season. The first harvest occurs in early to mid-July and second at the end of the season in late September or early October. Adequate stubble height is essential to sustain the crop. As a biomass managed crop for ethanol production and maintenance of adequate stubble, long-term survival should likely not be an issue. Switchgrass is a viable crop in the warm regions of the PNW if natural rainfall is adequate or irrigation water is applied.