Weed-Killing Robot

Imagine a robot killing Palmer Amaranth in your field with a rotating cylinder about the size of a rolling pin in your kitchen and applies herbicide like a honey dripper. A University of Nebraska professor of chemical and biological engineering is working on it. Henk Viljoen’s goal is to spot-treat weeds in a way that eliminates the risk of herbicide drift, and also minimizes exposure of crops and soil to the chemical.

He says the first step in the process is flying a drone over fields, collecting images and GPS locations of the noxious weed. Those coordinates are then given to a self-driven robot, which drives itself to those sites.

"At the front end is this roller and it is hollow in the middle so that is where you fill it up with herbicide, and then through holes it wicks toward the surface. The whole thing is rotating at a specific speed so that it stabilizes the film on the roller," says Viljoen. "And then, it just drives itself down the rows and it contacts the weeds with the roller."

The roller deals a secondary blow to weeds – it has a serrated surface.

"It’s like small teeth that sit on the surface of the roller," he says. "And so by spinning, it actually tears up the epidermis of the weed’s surface and so when it contacts with the herbicide it’s taken up into the plant’s vascular system much faster than just by contacting alone."

He says so far, a prototype has been tested in small studies in a greenhouse. This summer, they’re testing it at a university field plot.