Switchgrass Response to Cutting Frequency and Biosolids Amendment: Biomass Yield, Feedstock Quality, and Theoretical Ethanol Yield
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Biofuel crops have relatively low economic value, and potential to grow them with low-cost inputs is essential for economic viability. Use of biosolids as a fertility source has not been explored at the field scale for switchgrass (Panicum virgatum L.), a potential bioenergy crop. This study tested harvest management and biosolids rate effects on switchgrass production, quality, and theoretical ethanol yield in Virginia, USA. Switchgrass (cv. “Cave-in-Rock”) was annually cut once (winter) or twice (summer and winter) for 2 years. Biosolids were applied once at 0, 77, and 154 kg N ha−1 in May 2011; urea was applied once at 146 kg N ha−1 for comparison. Feedstock yield and quality parameters (neutral and acid detergent fibers, cellulose, hemicellulose, lignin, and ash) were measured and used to compute theoretical ethanol potential (TEP) and theoretical ethanol yield (TEY). Cutting twice per season produced greater biomass yields than cutting once (6.6 vs 5.4 Mg ha−1) in 2011 but not in 2012. Cutting once per season produced feedstock with greater TEP (513 vs 433 L Mg−1) and TEY (2,980 vs 2,680 L ha−1) in both years. Biosolids and urea increased biomass yields by 11 % (0.6 Mg ha−1) and TEY by 13 % (352 L Mg−1), but both decreased TEP by 1 % (7.1 L Mg−1 biomass). Cutting once per season is advantageous in producing more TEY given comparable biomass yield and superior feedstock quality. Biosolids were a suitable alternate N source and could boost biomass and biofuel production while reducing input costs in switchgrass-based bioenergy systems.
KeywordsBioenergy crop Nitrogen fertilization Biofuel quality Feedstock cellulose Grass cell wall Organic fertilizer
The authors thank James Mahan for providing a field site and conducting all field operations, Chris Fields-Johnson and Tianyu Lei for assistance with sample collection, and Steve Nagle for assistance with sample analysis. Funding for this research was provided in part by the DC Water (formerly the District of Columbia Water and Sewer Authority).
- 2.Lemus R, Brummer EC, Burras CL, Moore KJKJ, Barker MFMF, Molstad NENE, Charles Brummer E, Lee Burras C (2008) Effects of nitrogen fertilization on biomass yield and quality in large fields of established switchgrass in southern Iowa, USA. Biomass Bioenergy 32:1187–1194. doi: 10.1016/j.biombioe.2008.02.016 CrossRefGoogle Scholar
- 5.Fike JH, Parrish DJ, Alwang J, Cundiff JS (2007) Challenges for deploying dedicated, large-scale, bioenergy systems in the USA. Perspect Agric Vet Sci Nutr Nat Resour 2:1–28Google Scholar
- 15.Ashworth AJ (2010) Biomass production and nutrient removal of switchgrass as a bioenergy feedstock. University of Arkansas pp. 81Google Scholar
- 19.Gunderson C, Davis E, Jager H, West T, Perlack R, Brandt C, Wullschleger S, Wilkerson E, Downing M (2007) Exploring potential US switchgrass production for lignocellulosic ethanol. Tech Manuscr ORNL/TM-2007/183 Oak Ridge National Laboratory, Oak Ridge, TennesseGoogle Scholar
- 39.Coble CG (1989) Harvesting strategies for high yielding biomass crops. Energy Biomass Wastes XII:361–377Google Scholar
- 40.Lötjönen T (2008) Harvest losses and bale density in reed canary grass (Phalaris arundinacea L.) spring-harvest. Asp Appl Biol 90:263–268Google Scholar
- 47.VADCR (2005) Virginia nutrient management standards and criteria. Richmond, VA. 1–117.Google Scholar