Weeds, meet laser
The future for the control of weeds is looking bright. Just about as bright as lasers guided by artificial intelligence to hunt down and zap weeds.
An artificial intelligence-powered technology that hunts weeds and zaps them with a laser has been created by Agresearch. It’s delivered through a robot and powered by AI under a system called ‘Map and Zap’, which could be used in orchards, vineyards or a field growing vegetables or pasture.
The system was designed by a group of Agresearch scientists and engineers led by Dr Kioumars Ghamkhar.
On a visit to a friend’s farm, Ghamkhar had a conversation that would ring a bell with many farmers. “She was telling me that if we want to serve the farmers of the world, we should find a permanent solution for weeds.
“It’s a problem for everyone, it doesn’t matter what kind of farming you do. When I thought about precision agriculture, I did a review and found there were people working on automated weeding.
“Then I thought, the best form of precision agriculture is probably lasers, nothing is more precise than lasers.”
Ghamkhar caught up with a laser scientist from Auckland University who was initially hesitant ablout zapping weeds with lasers.
But when the man got into the field to test the system, Ghamkhar says you couldn’t stop him.
“I’m also a big fan of lasers from my childhood,” he jokes.
Almost $1.7 billion was spent on control measures for pests and weeds in New Zealand for the 2019 to 2020 financial year.
While the system won’t eliminate the use for herbicides, Ghamkhar says it can reduce it.
Precision spraying should not be undervalued, he says, but you can’t get more precise than a laser. “I don’t think anyone could argue that. People use lasers to shoot missiles, right? But we’re using it for a good reason.”
Agresearch has been developing the AI system since 2020. Kiwinet, an innovation organisation that commercialises research, provided the robot-prototype to deliver the system for the weeds to be hunted down.
The robot’s lasers were put to the test in a recent demonstration at Canterbury vineyard Straight 8 Estate.
Co-owner James Shand has been in the business for 20 years now and is impressed with how much technology has changed over the years.
“It’s amazing because the technology in the early seventies was an old 44-gallon drum on the back of a tractor tray to spray weeds, and a man with a gorse gun.”
Shand says there are two or three weeds that intrude on his vines, particularly the Californian thistle.
“Californian thistles are the worst ... they grow into the wire where the grapes are. When they go to seed, they make pollen that glues to the grapes.”
He doesn’t mind the weeds that flower, as they provide nutrients to the soil, but the best thing about the technology for him
is its ability to target the weeds that seed, spread and suck up nutrients.
At first, Shand was doubtful of the technology as he was so used to his regular control methods, like his four-legged weed mowers – his sheep.
But in knowing how many chemicals go into fruit and vegetables, he was open to seeing what the technology could do.
“Then I saw how they could actually pinpoint a weed and how quickly the weed disappeared. The thing with weed spray, it does last longer, but there’s no instant turnaround.
“What I really liked about their piece of machinery was that it wasn’t over-complicated. I could understand the gist of why and how it works.’’
With the extra funding and development, Shand expects the system to save a lot of time, effort and machinery.
Australasia’s managing director for agritech firm Cropx, Eitan Dan, was impressed by the system’s ability to target only unwanted plants and weeds in their early stages of growth, trained by AI to distinguish between different weeds.
“I think this is the exact thing when you are saying ‘precision agriculture’. You are dealing precisely with a problem without harming everything around it,” Dan says.
Ghamkhar says: “It’s so smart, the system detects weeds at the two or three-leaf stage. Even if the crop has two or three leaves as well, it will just target the weed because it knows what it is at species level.’’
The AI has been trained by human intervention to recognise different plant species and can detect up to six species at one time.
The system has been tested in vineyards that have many weeds, including clover. But Ghamkhar says some vineyards do not want to kill their clover, so the unit can identify that within the crop, avoid it and kill other unwanted weeds.
He is yet to discover the full potential for lasers, but says the ‘Map and Zap’ system is a decent starting point.
“There’s a lot of uses to come for us to understand the amazing things lasers can do. One of the most interesting for my field, which is plant science and agriculture, was this.”
“It’s a problem for everyone, it doesn’t matter what kind of farming you do.’’ Dr Kioumars Ghamkhar