Peak Water?

Growing corn to make ethanol can require substantial quantities of water—from 7 to 321 gallons per gallon of ethanol produced—depending on where it is grown and how much irrigation water is used.  In addition, corn is a relatively resource-intensive crop, requiring higher rates of fertilizer and pesticide applications than many other crops; some experts believe that additional corn production for biofuels conversion will lead to an increase in fertilizer and sediment runoff and in the number of impaired streams and other water bodies. Some researchers and conservation officials believe that the impact of corn-based ethanol on water supply and water quality could be mitigated through research into developing additional drought-tolerant and more nutrient-efficient crop varieties, which would reduce the amount of water needed for irrigation and the amount of fertilizer that needs to be applied.