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Using a blimp fitted with cameras,
University of Georgia researchers are working on a system
cotton farmers can use to water their crops when they need
it.
Plants reflect light in unique ways, said Glen Ritchie, a
research coordinator with the UGA College of Agricultural
and Environmental Sciences. “Most of the visible light
plants reflect is green,” Ritchie said. “But they
also reflect near-infrared light that we can’t see with
our eyes.”
Since the 1960s, scientists have known that how a plant reflects
light can say a lot about its health. This knowledge can be
used to properly schedule irrigation, too, Ritchie said. You
just have to get a camera high enough to take a good picture
of the field.
From the ground Ritchie presses a button on a radio transmitter,
sending a signal to an adapter hooked into the serial ports
of two cameras inside a small plastic container hanging three
feet below the blimp’s belly. The two cameras are off-the-shelf
Nikons. One takes a regular image. The other, fitted with
a near-infrared filter, takes a near-infrared image.
At 300 feet, the cameras can take a picture of about an acre
of land, an area about the size of a football field. Two people
can control the blimp using two ropes attached to it. They
can cover the 5-acre field in about 10 minutes.
Ritchie downloads his images to a computer. Software combines
and analyzes the images and compiles the data into spreadsheets
that can be used to make irrigation decisions.
Ritchie hopes to establish benchmarks, or triggers, with the
data. This could give a farmer a window of a day or more to
begin irrigating his crops.
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