SWITCHGRASS AND MISCANTHUS YIELDS ON RECLAIMED SURFACE MINES FOR BIOENERGY PRODUCTION

Abstract

Abstract. Legislation passed by the U.S. Congress in 2007 mandates that 25% of transportation fuels must be made from renewable sources by 2022. Two bioenergy crops that have the potential to meet this mandate are switchgrass (Panicum virgatum) and Miscanthus (Miscanthus x giganteus). Both species are warm-season perennial grasses and have high biomass production potential under low soil fertility requirements. Biofeedstocks for transportation fuels should be grown on marginal lands rather than prime agricultural land best suited for growing food crops. West Virginia provides an abundance of reclaimed surface mine lands that could be used to produce bioenergy crops. In 2010, two varieties each of switchgrass and Miscanthus were planted in 0.4-ha plots with five replications. This study determined dry matter yields of switchgrass varieties Kanlow and BoMaster and Public and Private varieties of Miscanthus after five growing seasons. All species and varieties were established at Alton, a reclaimed surface mine in central West Virginia. This site was reclaimed in 1985 with 15 cm of soil being placed over mixed overburden. Grass and legume species were planted and soils were initially fertilized and limed according to recommendations. Miscanthus yields after the 5 th year averaged 13.7 Mg ha -1 for Private and 14.4 Mg ha -1 for Public. Switchgrass yields after five years averaged 7.9 Mg ha -1 for Kanlow and 7.3 Mg ha -1 for BoMaster, which is approaching the yields of switchgrass on agricultural soils in the region. With these recorded biomass yields, switchgrass and Miscanthus are able to provide alternative, more sustainable energy sources, whilst providing a more profitable post-mining land opportunity for surface mined land-owners.