Boosting ethanol production by growing more corn in the United States without considering the quality and availability of water by region could put a significant strain on water resources in some parts of the country, a committee of the National Research Council said in a report released this week.
The report's authors, who include Professor Dara Entekhabi of MIT's Department of Civil and Environmental Engineering, recommend that conversion of U.S. agriculture to biofuel cultivation should only be undertaken in tandem with regional water assessments, the adoption of environmentally sound farming practices, and consideration of the full life cycle of biofuel production.
"Agricultural shifts to growing corn and expanding biofuel crops into regions with little agriculture, especially dry areas, could change current irrigation practices and greatly increase pressure on water resources in many parts of the United States," the committee said in its report, released Oct. 10. "The amount of rainfall and other hydroclimate conditions from region to region causes significant variations in the water requirement for the same crop."
The report also urged big agriculture to adopt new technologies that can increase crop yield while conserving water and reducing negative environmental impacts, such as soil erosion and runoff pollution.
"We must recognize that the current state of the U.S. agroecosystem is not sustainable," said Entekhabi, a hydrologist who studies land-atmosphere processes and is director of MIT's Parsons Laboratory for Environmental Science and Engineering. "The use of energy-intensive and industrially produced fertilizers and pesticides are finding their way into water and food supplies for humans and animals. Soil erosion and loss of soil fertility is continuing unabated. U.S. agriculture needs to shift to more ecologically sound and sustainable conditions."
Corn ethanol production in the U.S. is ramping up, in part due to President George W. Bush's call for a dramatic increase in the production of ethanol over the next decade. The National Research Council convened the committee to look at the effect energy crops would have on the nation's agriculture and water management, as well as the long-term sustainability of meeting the president's demand that by 2017, 15 percent of the nation's liquid fuel be biofuel.
Other recommendations of the committee include looking at the possibility that biofuel crops could be irrigated with wastewater that is biologically and chemically unsuitable for use with food crops; the development of water-efficient genetically modified crops for biofuels production; and the minimization of erosion by producing biofuels from perennial crops such as switchgrass, which hold soil and nutrients in place better than most row crops.
The McKnight Foundation, the Energy Foundation, the National Science Foundation, the U.S. Environmental Protection Agency, and the National Research Council Day Fund sponsored the study.
A version of this article appeared in MIT Tech Talk on October 17, 2007 (download PDF).