An Economic Assessment of Nutrient Removal from Switchgrass Production

The on-site loss of nutrients due to biomass removal creates additional costs for ethanol production however this aspect has not been properly incorporated in economic analyses of biomass production and processing. This study investigates costs of on-site nutrient losses in switchgrass fields in Tennessee. The replacement cost methodology was applied to measure on-site cost of nutrient losses due to biomass removal and was based on the costs of replacing nutrients removed from the production site. The estimated costs for total on-site nutrient loss due to biomass removal show a substantial loss of nutrients in switchgrass fields. The loss of major nutrients from biomass removal represents the major part of on-site economic costs. A declining trend of nutrient costs per Mg of harvested biomass was observed with increasing in harvesting time. The internalization of on-site costs of nutrient losses is possible by adopting an appropriate harvest schedule for switchgrass.