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.

Growing Dedicated Energy Crops on Marginal Lands and Ecosystem Services

“…Biomass production on floodplains, however, can be lower than on prime agricultural lands. For example, in a study in the southeastern United States, Alamo switchgrass yielded higher on well-drained upland soils (17.7 Mg ha −1 ) than floodplain soils (8.5 Mg ha −1 ) under different N fertilization rates (0, 67, 134, and 201 kg N ha −1 ; Mooney et al, 2009). The same study found that the maximum switchgrass yields occurred at 67 kg N ha −1 on the well-drained soil and at about 160 kg N ha −1 on the poorly drained floodplain, suggesting that marginal lands can require higher rates of N fertilizer than prime farmlands to produce the same amount of biomass.…”

“…The drainage class will influence the energy crop performance. Floodplain soils severely limited by poor drainage (Mooney et al, 2009) can yield less biomass than moderately drained floodprone soils (Evers et al, 2013).…”

Economic Feasibility of Using Switchgrass Pasture to Produce Beef Cattle Gain and Bioenergy Feedstock

“…Effects of treatment (stocking rate) on feedstock yield and measures of animal performance (average daily gain and total gain) and economic performance (net return) were analyzed using random-effects mixed ANOVA models using the PROC Mixed procedure in SAS [34,35]. Stocking density treatment (light, moderate, and heavy) was considered as a fixed effect, and year was considered as a random effect.…”

Yield, Yield Distribution, and Forage Quality of Warm-Season Perennial Grasses Grown for Pasture or Biofuel in the Southern Great Plains

“…According to the 2007 Census of Agriculture, Oklahoma ranks fifth nationally in cattle and calves and fourth in acres in forage, while Texas ranks number one in both of these categories. The Energy Independence and Security Act of 2007 calls for 136 billion liters of biofuels to be produced from renewable resources in the US by 2022 with just under half to be produced from a cellulosic biomass source such as switchgrass [1]. To meet the demand for cellulosic ethanol production called for in The Energy Independence and Security Act of 2007, could require the conversion of acreage currently established in perennial grasses to higher biomass producing grass species such as switchgrass.…”