Researchers in Kansas have developed a system that will spray
individual weed patches as the sprayer finds them, rather than covering
an entire crop with herbicide.
“Both from an environmental and cost perspective this is an improvement
on our current technology,” said Floyd Dowell, an engineer at the
United States Department of Agriculture research centre in Manhattan,
Kansas.
Dowell worked with several groups and universities to develop the
technology.
“We can identify specific weeds and turn on the spray nozzles
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individually as necessary to spray only that area. This is particularly
a problem for grassy weeds in cereal crops where patches are common but
not uniform across the whole field,” he said.
“It prevents wasting spray. That is friendly to farmers’ bottom lines
and to their environment,” said Dowell.
The system uses an optical sensor that is “trained” to recognize
individual weeds by the way they reflect light.
Using a near infrared spectrometer, the team of researchers examined a
variety of crops and found five wavelengths of light that identify a
number of weeds and differentiate them from crops or soil.
The sprayer operator starts by teaching the computer controller to
recognize weeds in the field, by holding a weed in front of the
specially designed optical sensors.
The controller records the light reflection characteristics of the weed
and stores this data so that the sprayer will recognize individual
plants as it passes over them.
In testing this summer, the prototype sprayer was more than 95 percent
accurate in detecting weeds and applying spray to them.
Dowell said more work is needed to refine the equipment and test it,
but feels the technology should be ready for commercialization within
the next three years.
