Switchgrass Potential on Reclaimed Surface Mines for Biofuel Production in West Virginia

Abstract

The high cost and environmental risks associated with non-renewable energy sources has caused an increased development of renewable biofuels. Switchgrass (Panicum virgatum L.), a warm-season perennial grass, has been investigated extensively as a source of biofuel feedstock due to its high biomass production on marginal soils. Additionally, the plant's high tolerance to adverse growing conditions and its ability to provide habitat for wildlife makes it a widely used species for conservation cover. West Virginia contains vast expanses of reclaimed surface mine lands and could potentially benefit from the production of switchgrass as a biofuel feedstock. Furthermore, switchgrass production could satisfy Surface Mining Reclamation and Control Act of 1977 (SMCRA) requirements for reclamation bond release to mine operators. This study examined yield of switchgrass stands grown on reclaimed surface mines during the third and fourth years of production. Three varieties were tested on two mine sites to determine which produces the highest yields on reclaimed surface mines in West Virginia. The Hamphire Hill mine site which was reclaimed in the early 1990s using top soil and treated municipal sludge consistently had the highest yields of the two sites (2,566 kg/ha averaged across three years). The other mine site, Hobet 21, was prepared using crushed, unweathered sandstone as the soil material, and yields of switchgrass were 975 kg/ha averaged over three years. Cave-in-Rock variety produced more biomass than the other two varieties, Shawnee and Carthage. A second study to determine optimal nitrogen rates for switchgrass established on newly reclaimed surface mines was launched in June 2011 on two new surface mine sites. Both sites were seeded at a rate of 11.2 kg pure live seed (PLS) ac-1 on replicated treatments of 0, 33.6 and 67.0 kg N ha-1. Results showed that a fertilizer treatment of 33.6 kg ha-1 and 67.0 kg ha-1 at seeding produced a higher yield compared to yields from plots with no fertilizer and the plants looked more vigorous and provided greater ground cover. Plots fertilized with 0, 33.6, and 67.0 kg ha-1 produced average yields of 67, 367 and 777 kg ha-1 , respectively. No significant difference was found between the high and low N applications.

Reclamation of Mined Land With Switchgrass, Miscanthus, and Arundo for Biofuel Production

“…Weeds were found in appreciable quantities in the stands during the first and second years after planting, but they declined in 2012 as the switchgrass shaded and out-competed the weeds. Switchgrass stands do not develop fully until after the third growing season (Marra and Skousen, 2012). Therefore with less competition from weeds and greater stand density and growth, target yields are anticipated to be reached.…”

“…Switchgrass has been used in reclamation studies on roadsides (Skousen and Venable, 2008), surface mines (Skeel and Gibson, 1996;Marra and Skousen, 2012;Dere et al, 2011), sand and gravel mines (Gaffney and Dickerson, 1987), lignite overburden (Skousen and Call, 1987), and Pb and Zn mines (Levy et al, 1999). In 2008, switchgrass trials were established for bioenergy production in West Virginia (Marra and Skousen, 2012). They found that switchgrass on reclaimed land with topsoil produced yields of nearly 7,000 kg ha -1 , but yields were three times lower (2,000 kg ha -1 ) on reclaimed lands with no topsoil.…”