Environmental and economic analysis of switchgrass production for water quality improvement in northeast Kansas

The primary objectives of this research were to determine SWAT model predicted reductions in four water quality indicators (sediment yield, surface runoff, nitrate nitrogen (NO3–N) in surface runoff, and edge-of-field erosion) associated with producing switchgrass (Panicum virgatum) on cropland in the Delaware basin in northeast Kansas, and evaluate switchgrass break-even prices. The magnitude of potential switchgrass water quality payments based on using switchgrass as an alternative energy source was also estimated. SWAT model simulations showed that between 527,000 and 1.27 million metric tons (Mg) of switchgrass could be produced annually across the basin depending upon nitrogen (N) fertilizer application levels (0–224 kg N ha−1). The predicted reductions in sediment yield, surface runoff, NO3–N in surface runoff, and edge-of-field erosion as a result of switchgrass plantings were 99, 55, 34, and 98%, respectively. The average annual cost per hectare for switchgrass ranged from about $190 with no N applied to around $345 at 224 kg N ha−1 applied. Edge-of-field break-even price per Mg ranged from around $41 with no N applied to slightly less than $25 at 224 kg N ha−1 applied. A majority of the switchgrass produced had an edge-of-field break-even price of $30 Mg−1 or less. Savings of at least 50% in each of the four water quality indicators could be attained for an edge-of-field break-even price of $22–$27.49 Mg−1.