Weed killers, herbicides in techno-speak, must be toxic enough to
kill the weeds they target. Thus, toxicity concerns -- ranging from
protecting the workers using the chemicals to g
roundwater contamination -- confront any user of herbicides.
Researchers at the Leibniz University in Hannover, Germany, may have an answer:
weed-killing lasers.
Farming with Laser Death Rays
Sounds like a great idea? It is not so easy though. If the lasers used
have too little energy, weeds like it. Laser lights of the wrong
intensity make the unwanted plants grow like weeds, only more so. The
Leibniz team has worked to determine the optimum laser intensity to kill
the weeds rather than encourage growth.
The second major obstacle is recognizing which plants to target with
the laser death rays. The researchers have developed a system of cameras
that film the field, and software that measures the contures of every
plant. Algorithms have been developed for recognizing many different
types of weeds.
The system currently can treat about a square
meter of growth in a greenhouse, where the apparatus can be mounted on
rails for pin-point control. The scale-up for larger greenhouse
applications or orderly plantations where equipment can run on rails up
and down rows of vegetation can be easily conceived.
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