Unmanned aircraft will replace topdressing pilots in the agriculture industry within 15 years, a Canterbury drone engineer predicts.
SPS Automation chief executive and technology officer Scott Spooner spoke at the Beef + Lamb New Zealand field day Farming in the Future in South Canterbury this month.
About 100 people attended the event on a sheep and beef farm in Cave.
The mechatronics engineer said he expected nearly all agricultural spraying to be uncrewed within the next 15 years, such as drones and helicopters operating on auto-pilot.
SPS Automation, a research and development company based in Christchurch, specialises in novel aviation technology, such as drones.
All of its drones were designed in New Zealand and built in Washdyke, near Timaru.
A swarm of SPS Automation drones were used in a trial, launched by the Central Otago District Council and Central Otago Wilding Conifer Control Group, to spray chemicals on more than 300 wilding conifers across 500ha in Loganburn, between Roxburgh and Middlemarch, in February this year.
Wilding conifers often cover large areas in remote locations.
At the Loganburn site, there was about one tree per hectare.
Some of the tree locations could not be accessed by spray crew on the ground or by air.
"It was steep, rocky terrain, with overhangs."
Often agricultural drones on the market lacked the flight time required to get to a remote site due to the size of the battery.
"We had to reinvent how we were going to do it."
SPS Automation designed and made the Agri-copter AC-16 drone, which could fly for an hour by running on 95-octane petrol to increase its range.
The hybrid drones also featured "back-up" batteries.
A drone was used to survey the area for wilding conifers and used artificial intelligence to detect a type of tree, its size and record its GPS location.
From the map, an algorithm was used to create a flight plan so a swarm of drones could be deployed to spray the trees in the most efficient way.
"It makes getting out into those remote locations very, very easy."
The AC-16 drone, had a 120cc fuel-injected two-stroke motor and was available to buy for about $85,000.
Each AC-16 drone could carry up to 16kg of liquid to spot-spray.
About 200ml was sprayed on a 4m-high tree.
A downward-facing camera on the drone broadcasts video, allowing the operator to watch chemical being applied to a tree.
Spray marker was included in the liquid so the operator could "paint" a tree.
Consequently, a small amount of chemical could be applied accurately, he said.
The drones painted some trees when wind speed were up to 30kmh.
The drone swarm needed fewer than three days to spray the trees.
A return to the site about two months later showed a "100% kill rate" of the targeted trees.
"We were able to nail every single tree, which was really, really cool."
The drones had been used successfully in a trial spraying gorse bushes on steep terrain in the Hunter Hills in South Canterbury.
A swarm of up to four AC-16 drones could fit on a deck of a ute covered by a canopy, he said.
SPS Automation was developing a larger drone, Agri-copter BFD 70, for the forestry industry to use for spot spraying.
He expects the BFD 70 to be available to buy for about $150,000 next year.
The initials BFD stands for "big friendly drone", a play on Roald Dahl’s book BFG, an abbreviation for Big Friendly Giant.
The BFD 70 drone holds up to 50 litres of spray and could fly for two hours at a time.
It had a 350cc fuel-injected two-stroke engine.
The drone could be connected to Starlink satellite technology so it could be operated remotely.
A drone being able to connect to a satellite, allows it to be operated in remote locations, out of the visual sight of its operator.
"It is a real game-changer."
