SALIX SPP. AS A BIOMASS CROP: INVESTIGATING ITS POTENTIAL ON MINED LANDS AND THE USE OF BIOCHAR AS A SOIL AMENDMENT

Abstract

Rising energy demands and costs have increased the need to develop alternate sources and markets. Biomass plantations are proposed as part of the renewable energy solution. In West Virginia, over 50,000 acres of previously mined and reclaimed land are suitable for cultivation with bioenergy crops, including woody plants. The feasibility of growing shrub willow (Salix spp.) for the dual purpose of restoration and biomass crop production was assessed on reclaimed surface mines and fallow agricultural land in West Virginia. Replicated field trials were established and monitored over one growing season at four sites throughout the state. Within the field trials, biochar was tested as a soil amendment to mitigate soil quality issues associated with mine soils and fallow agricultural land. To characterize Salix spp. potential as a feedstock, proximate analysis, ultimate analysis, and heating value were measured. Wood properties for one-year-old material were compared with the specifications required for woody biomass combustion or ethanol production. Relative to these specifications, ash content was slightly higher (2.7% vs. 1.0%) as was nitrogen (0.98% vs. 0.35%), whereas volatile matter was lower (79.8% vs. 82.0%). Based on these standards, Salix spp. grown on reclaimed surface mines or fallow agricultural sites appears to be a suitable biomass feedstock for combustion and biofuel production. Biochar improved growth 80.7% and yield 72.4% compared to non-amended plots. Improved growth and yield in biochar-amended plots in the first year of growth gave willow saplings a competitive advantage over weeds. Additionally, biochar has shown long-term positive impacts in field studies, and improved growth and yield during the first year may prove to give higher yields in the long term.