that reinvigorated many small midwestern communities, but some argue that the number of jobs added to the local economy is overestimated (Low and Isserman, 2009). For farmers, the increase in corn grain prices, which averaged $2.36 ± 0.40 per bushel of grain (25 kg) in 1973–2005 but $3.04 and $4.00 per bushel in 2006 and 2007 (USDA-NASS, 2008a), was of great importance. The increased prices were results of an increased global demand for corn as animal feed and for grain ethanol production. Higher commodity prices have also led to markedly higher values of fertile farmland, and have adversely affected low-income consumers in the United States and abroad and the drawing of land out of the U.S. Conservation Reserve Program (CRP). On a global scale, high commodity prices are expected to accelerate clearing of rain forest and savanna. There is growing concern about the use of grain for fuel instead of food. Other environmental concerns, especially the loss of nitrogen by leaching (Donner and Kucharik, 2008), have also been pointed out. Corn and soybean are renewable biofuel feedstocks, but large amounts of fertilizer and pesticide are often needed to grow them (Hill et al., 2006). The resulting greenhouse gas and other pollutant effects of those practices can be harmful to human health and the environment.
Corn grain ethanol and soybean biodiesel are viewed by some as intermediate fuels in the transition from oil to advanced biofuels made from cellulosic biomass. As a biofuel feedstock, cellulosic biomass has numerous advantages over food and feed crops, including its availability from sources that do not compete with food and feed production. Biomass can be reclaimed from municipal solid-waste streams and from residual products of some forestry and farming operations. It can also be grown on idle or abandoned cropland, on which food or feed production is already minimal. Growing cellulosic biomass can require less fossil fuel, fertilizer, and pesticide inputs than growing corn and soybean (Tilman et al., 2006), especially if legumes (nitrogen-fixing plants) are included in the mix (NRC, 1989). In addition, cellulosic biomass can serve not only as a feedstock for biofuel production but also as a source of the heat and power required for biorefineries and thus displace fossil fuels and fossil-fuel-derived electric power (Morey et al., 2005). Therefore, this chapter focuses on the biomass resources available for cellulosic biofuel production.
Globally, about 12 billion acres of land are used for agriculture, about 4 billion of which are cultivated and the remainder used for grazing. Any substantial