THE future of crop weeding comes in the form of a robot and arises out of necessity.
Extension specialist Steven Fennimore of the University of California, Davis, says the robotic weeders are needed for specialty crops such as lettuce, broccoli, tomatoes, and onions because they are not mass produced.
The demand stems from two issues – a lack of herbicides available for use in specialty crops, and hand-weeding has become increasingly expensive. Without pesticides, growers have had to hire people to hand-weed vast fields.
Fennimore says hand-weeding is slow and can cost US$150-US$300 (£110-£220) an acre, motivation enough to see growers looking to robotic weeders.
Fennimore works with university scientists and companies to engineer and test the weeders. The robots use tiny blades that pop in and out to uproot weeds without damaging crops. He says that although the technology isn’t perfect, it’s getting better and better.
The weeders are programmed to recognise a pattern and can tell the difference between a plant and the soil. However, they still have trouble telling the difference between a weed and a crop.
That said, Fennimore explains how some companies are training the machines to tell a lettuce plant from a weed. He’s also working with university engineers on a system to tag the crop plant so the weeders will avoid it.
“The problem with the machines right now is that they are version 1.0, and there’s tremendous room for improvement,” he says.
“The inability to be able to tell the difference between a weed and a crop requires the grower to be very exact when using them.”
Those on the market cost between US$120,000 and US$175,000 (£88,685 and £129,332). For some California growers, it is a better long-term option than expensive hand-weeding.
Fennimore says others think it’s a lot of money for a new technology, and are waiting for it to get better and cheaper.
He believes robotic weeders are the future of weeding in specialty crops. Because of higher labour costs and more incentives to grow organically with fewer pesticides, European growers have been using robotic weeders for some time.
Fennimore is focusing his work on physical control of weeds because it offers the best option.
He’s also started working in crops besides lettuce, such as tomatoes and onions. He says each crop will require a different system.