Carbon Dynamics in Bioenergy Production Systems on Marginal Land.

Revegetation of mined land with cool season forage grasses is the most common reclamation practice adopted specifically for soil erosion preventive measures and improving wildlife habitat or rangeland. However, this land is underutilized when compared to the future economic potential through production of bioenergy crops. Once soil physical (low available water capacity, high compaction), chemical (pH, lack of nutrients, plant toxicities), and biological (microbial actives, soil organic carbon) properties have been appropriately amended, miscanthus and switchgrass have a large potential as biomass energy crops in minesoils in the Appalachian region. Additionally, productivity of minesoils and C sequestration can be increased by application of organic amendments instead of inorganic fertilizers such as sewage sludge, animal manures, and anaerobic digestate as they not only provide plant nutrients, but also organic C to the soil to stimulate microbial activity and soil aggregation. The objectives of this study were to quantify the effects of land application of effluent from anaerobic digestion on soil organic carbon, microbial biomass carbon, and carbon loss via microbial respiration in a minesoil under existing C₃ forage grasses, miscanthus and maize production for bioenergy. Additionally, to determine if these management systems were a sink or source of C, net ecosystem productivity was estimated during the first two years of land use changes.