Renewable Farming

Big step toward robotic weed control: Crops that emit a special frequency

We’ve long hoped for a robotic, GPS-controlled laser “cultivator” that would whack weeds out of crops. 

Scanning leaf shapes would be one way for the system to tell weeds from corn or beans. But a more practical way is already under development: Seed treating crops with a marking compound which causes the growing crop’s leaves to emit a special frequency under an “exciter” light. 

Chris Bennett, Farm Journal Technology and Issues Editor, reports on this concept in a Dec. 3 web report at this link. His source:  Prof. David Slaughter of the UC Davis Department of Biological and Ag Engineering. 

The crop’s seed is treated with a systemic  chemical which the roots absorb and carry throughout the emerging leaves. When a cultivator passes, a special frequency of light shines on the crop and the leaves emit a response frequency which the cultivator’s sensors pick up and define as “Good plant… don’t destroy.” The data picture is instantly analyzed by an onboard computer, and instructions are fed to the “destruct” mechanism.

All non-responding vegetation becomes a target for destruction. If the “kill” mechanism is a laser, it would target and toast the weeds.

Of course, the major seed firms are probably already working on genetic insertions that would produce frequencies that a machine could sense. Their reasoning: A seed treatment might be also picked up by weed seeds germinating next to the crop, so the weeds can take on the camouflage of the nearby chemical. 


Meanwhile it would be a relief to think  that this type of cultivator could be used for organic crops as well as conventional. Weeds couldn’t develop resistance, and toxic residues wouldn’t occur.