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http://www.nsf.gov/news/news_summ.jsp?cntn_id=121480&org=NSF&from=newsPress Release 11-176
Testing the Water for Bioenergy Crops
Water significant limiting factor in growing crops like switchgrass
August 29, 2011Energy researchers and environmental advocates are excited about the prospect of gaining more efficient large-scale biofuel production by using large grasses like miscanthus or switchgrass rather than corn.
They have investigated yields, land use, economics and more, but one key factor of agriculture has been overlooked: water.
"While we are looking for solutions for energy through bioenergy crops, dependence on water gets ignored, and water can be a significant limiting factor," said Praveen Kumar, an environmental engineer and atmospheric scientist at the University of Illinois at Urbana-Champaign.
"There are many countries around the world that are looking into biofuel energy, but if they are adopting these
into their regular policy, they need to take into account the considerations for the associated demand for water."
Kumar led a study, the results of which are published this week in the journal Proceedings of the National Academy of Sciences, detailing links between the hydrologic cycle and large-scale land conversion, both now and as growing conditions change in the future.
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The result of large-scale adoption would be a reduction in soil moisture and runoff, but an increase in atmospheric humidity.
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Using the predictive model, the researchers found that net water use will increase further as a result of rising temperatures and carbon dioxide
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This additional water loss compounds the increase in water usage from land conversion.
In the U.S. Midwest, rainfall should remain sufficient to meet water demand, according to Kumar.
However, areas that rely on irrigation could find they have less water to meet higher demands, which could increase the net cost of large-scale land conversion and put pressure on already stressed water resources.
"If we're going to solve energy problems through bioenergy crops, there are collateral issues that need to be considered," Kumar said.
"Water is a significant issue. It's already a scarce resource across the globe, and the need for it is only going to increase. The cost of that should be factored in to the decision making."
… http://dx.doi.org/10.1073/pnas.1107177108