Water Footprints of Cellulosic Bioenergy Crops: Implications for Production on Marginal Lands

Thursday, 18 December 2014
Mir Zaman Hussain, Michigan State University, Great Lakes Bioenergy Research Center, East Lansing, MI, United States, Stephen K Hamilton, Michigan State Univ, Hickory Corners, MI, United States, Ajay K Bhardwaj, Central Soil Salinity Research Institute, Haryana, India, Bruno Basso, Michigan State University, East Lansing, MI, United States, Michael G Abraha, University of Toledo, Hickory Corners, MI, United States and G Philip Robertson, Michigan State University, Hickory Corners, MI, United States
Water availability often limits crop production, even in relatively humid climates, and crops vary in their water demand and water use efficiency. Crop production for biofuel (ethanol or biodiesel) offers an alternative to fossil energy sources but requires large amounts of land, and is therefore a more viable option if such crops could be produced on marginal lands that often have soils of poor water-holding capacity. The selection of an appropriate crop requires information on its water demand, water use efficiency, and drought tolerance, but such information is incompletely available for the suite of cellulosic biofuel crops currently under consideration. This study analyzed soil moisture profiles (time-domain reflectometry) to estimate evapotranspiration and water use efficiency of three leading candidate crops for cellulosic bioenergy production (switchgrass, Miscanthus, and maize) grown in a relatively humid climate (Midwestern United States) over four years (2010-13). These field observations of water use by these annual and perennial crops reveal their water use efficiency for biomass and biofuel production. Total growing season water use was remarkably consistent among crops and across years of varying soil water availability, including very favorable precipitation years as well as a drought year (2012). Water use efficiency was more variable and, for maize, depends on whether the maize serves for both grain and cellulosic biofuel production.