(July 6, 2015) Converting
large tracts of the Midwest’s marginal farming land to perennial biofuel crops
carries with it some key unknowns, including how it could affect the balance of
water between rainfall, evaporation and movement of soil water to groundwater.
In humid climates such as the U.S. Midwest, evaporation
returns more than half of the annual precipitation to the atmosphere, with the
remainder available to recharge groundwater and maintain stream flow and lake
levels.
A recent study from the Great Lakes Bioenergy Research
Center and published in Environmental Research Letters looks at how efficiently
“second generation” biofuel crops – perennial, non-food crops such as
switchgrass or native grasses – use rainwater and how these crops affect
overall water balance.
The study, led by Michigan State University professor of
ecosystem ecology and GLBRC scientist Stephen Hamilton, is the first multi-year
effort to compare the water use of conventional corn crops to the perennial
cropping systems of switchgrass, miscanthus, native grasses, restored prairies
and hybrid poplar trees.