The value of native, warm-season perennial grasses grown for pasture or biofuel in the southern Great Plains, USA

The Renewable Fuel Standard under the Energy Independence and Security Act of 2007 mandated the production of 60.5 GL (1 GL = 1 x 10(9) L) of cellulosic biofuel by 2022. Switchgrass (Panicum virgatum) has been identified as a primary feedstock because it is a perennial adapted to a wide environmental range and produces high yields. Development of the cellulosic biofuel industry has been slow, one reason being a lack of available feedstock driven by lack of a developed market. Rather than considering it only as a dedicated biofuel feedstock, we examined switchgrass potential for both grazing and biofuel feedstock. In a series of experiments testing dry matter yield, grazing preference and animal bodyweight gain, switchgrass (cv. Alamo) was found to produce greater total yield (17.7 kg ha(-1)) than 15 other warm-season perennial grasses, was the most preferred by stocker cattle in a grazing preference study, and produced good average daily gains in a grazing study (0.84-1.05 kg head(-1)). These results demonstrate the potential of switchgrass for both grazing and biofuel feedstock. However, the feedstock price would need to increase above US$83 Mg-1 before the economics of dedicated switchgrass feedstock production would surpass that of a combination of switchgrass grazing and feedstock production.