Bioenergy Crop Production with Marginal Irrigation Water.

In the recent years, interest in biobased fuels is increasing and the congressionally mandated goal is to use at least 36 billion gallons of bio-based transportation fuels by 2022. However, in 2009 the U.S. produced about 10.75 billion gallons of ethanol, primarily as corn starch ethanol and 550 million gallons of biodiesel. Thus, there is a huge gap between the current capacity and the mandated goal. Bridging this huge gap between current capacity and stated goal requires a comprehensive regional strategy that includes bringing addition area from different regions within the country under bioenergy crops. In the southwest U.S. region such as west Texas or southern New Mexico, bringing vast abandoned crop lands and areas having permeable soils under bioenergy crops can be a part of such a regional strategy. While the region has adequate supply of land, finding reliable source of water to produce bioenergy crops is the main challenge. This challenge can be met by developing marginal quality water sources for bioenergy crops production. Use of marginal quality waters such as treated urban wastewater/saline groundwater to irrigate bioenergy crops may prove beneficial, if the bioenergy crops can grow under elevated salinity and the effects on soil can be minimized by appropriate management. This paper presents first two years findings of a research project that is evaluating (i) the salt tolerance, biomass yield and bioenergy quality of switchgrass (Panicum virgatum L.); and (ii) changes in soil salinity due to urban wastewater irrigation under greenhouse conditions.