Warm Season Grass Production On Reclaimed Mined Lands.

Pennsylvania’s mined lands represent significant non-agricultural land area that could be converted to plant biomass production if suitably reclaimed. Experiments were established to investigate warm season grass production potential on an abandoned mined land (AML) site (2007) and an active mine site (2009) that were reclaimed using lime and fertilizer, composted poultry manure or poultry manure mixed with paper mill sludge (Man+PMS). Switchgrass (Panicum virgatum) was grown in monoculture in the AML experiment and in the active mine experiment 3 warm season grasses; Switchgrass, Atlantic Coastal Panicgrass (Panicum armarum) and big bluestem (Andropogon gerardii) were grown in monoculture and in polycultures of the 3 grasses and the 3 grasses with showy tick trefoil (Desmodium canadense) and birdsfoot trefoil (Lotus corniculatus). On the AML site switchgrass yield with compost and with Man+PMS reclamation were similar and averaged 4.6 and 5.0 Mg ha^-1 in years 3 and 4 respectively, double the yields with conventional lime and fertilizer reclamation. On the active mine site averaged across all species and cultures Man+PMS produced the largest, L+F the smallest and compost intermediate yields.  With all reclamation treatments Switchgrass and ACP produced the largest yields and Big bluestem the smallest. There was no clear yield increase from the polycultures. In year 3 switchgrass alone and the polycultures grown with Man+PMS produced similar yields averaging 5.8 Mg ha^-1. Although these yields are less than yields from prime agricultural lands, our results indicate significant warm season grass production could be achieved on reclaimed mined lands.