Yield and Breakeven Price of ‘Alamo’ Switchgrass for Biofuels in Tennessee

Abstract

Research on how land suitability affects yields and breakeven prices for switchgrass (Panicum virgatum L.) grown as a bioenergy crop is lacking for the U.S. Southeast. Data from a 3‐yr multilocation experiment at Milan, TN, were analyzed to determine the influence of soil drainage and landscape position on switchgrass yield and farm‐gate breakeven price. Plots were seeded in 2004 with ‘Alamo’ at 2.8, 5.6, 8.4, 11.2, and 14.0 kg ha−1 pure live seed (PLS). Plots were split in 2005 and N was applied at 0, 67, 134, and 201 kg N ha−1. Farm‐gate breakeven prices for 5‐ and 10‐yr production contracts were determined by calculating unit production costs from enterprise budgets that varied by input level and yield. Maximum yields occurred at 67 kg N ha−1 on well‐drained soils and at higher N levels on less‐well‐drained soils. Yield response to seeding rate (SR) was insignificant or small relative to other factors. Averaged across treatments, the well‐drained upland location suitable for row crops had the largest yield (17.7 Mg ha−1) and lowest breakeven price ($46 Mg−1) for a 10‐yr period. In contrast, the poorly drained flood plain location considered marginal yielded lowest (8.5 Mg ha−1) and had the highest breakeven price ($69 Mg−1). Breakeven prices were sensitive to yield, N price, and fuel price. Results suggest a lower breakeven price for switchgrass in the U.S. Southeast as compared with other U.S. regions, mainly due to high yields for the Alamo variety.