April 25, 2014
Better-bred crops could send global warming out to space
Scientists have used computer models to imagine a world where crops are specially bred to reflect away more light and heat, without compromising productivity.
The planet is losing its albedo, but new research suggests it could be perked back up using sexy new approaches to crop breeding.
Albedo refers to reflectiveness, and high albedos help keep the globe cool by reflecting light and heat back out to space. For every drip of sheer white ice that melts away from the Arctic, the planet’s albedo droops a little more, hurrying global warming along.
With farmed land covering so much of the planet—about 15 percent of its ice- and waterless area—scientists are looking for ways that agriculture can help slow down climate change. One strategy scientists are investigating is the modification of crops to boost their albedo.
Plants generally evolved to soak up as much of the sun’s light as possible. The sun-rays falling on green chloroplasts drive the photosynthesis that underpins most food chains. Sunlight hogging canopies can also help a plant keep would-be vegetative competitors in the dark—and at bay.
With farmed land covering so much of the planet—about 15 percent of its ice- and waterless area—scientists are looking for ways that agriculture can help slow down climate change.
A team of American scientists wanted to know whether it would be possible to redesign soy crop canopies to maximize albedo, improve yields, and reduce evaporation from leafs, which would help save water.
In the real world, this would involve breeding or engineering crops to change the angles and reflectiveness of leafs and the sizes of canopies. For their study, the scientists used a computer model of soybean fields growing in America’s corn belt, where soy and corn crops alternate.
The team used a high-resolution computer model that divided each hypothetical soybean plant’s canopy into 15 layers. They studied how tweaks to the leafs’ properties affected the crops during sunny days. In a paper published this month in Global Change Biolog y, the researchers reported that their simulated canopies were successfully reshaped to achieve “significant gains” in productivity, water use, and albedo.
The scientists discovered that crop productivity could be boosted by seven percent through canopy changes without changing water use or albedo. Alternatively, water use could be reduced by 13 percent without affecting harvest sizes. And by focusing just on albedo, the scientists found that one-third more of the sun’s rays could be mirrored away from soy fields than is currently the case—just by re-engineering the plants’ leaves, through strategies like manipulating known gene mutations.
“A previous study had generally looked at this possibility with corn; our study looks at soybean,” says Praveen Kumar, a professor in the University of Illinois’ civil and environmental engineering department. “Together, they constitute a large part of agricultural land. While we have not done it, there is no reason to believe that this is not possible for other crops.”
Kumar pointed out that water conservation and increased production have direct economic value to farmers. Changes to a farm’s albedo could, however, seem worthless to them. “Adoption can be facilitated by economic incentives, such as carbon credits, and policy changes,” he says.
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