Drone-mounted lasers to be studied in the war against weeds
Farmers may one day have a new high tech weapon in the war against weeds as AgResearch begins investigating whether drone-mounted lasers could be used to zap problem plants.
The project would have a camera mounted onto a drone or unmanned aerial vehicle (UAV) that identified weeds based on their chemical signatures and how they reflected light, programme leader Dr Kioumars Ghamkhar said.
The weed's locations were then mapped using GPS and the drone would then identify and eradicate the pest plant using a laser.
"From there, we think smart spraying [rather than blanket or non-targeted use of chemicals], or the right kind of laser mounted on the drone could hone in and damage the weed.
"We know there are lasers now available that could be suitable, and that they are extremely accurate, so if lasers are used, it would also avoid damaging the useful plants around the weed."
Identifying plants by their chemical signatures had worked in other projects. The challenge now was to accurately identify weeds so drone-mounted lasers could be effective, or equipment mounted on a drone could perform minimum targeted spraying, he said.
Weed control methods at the moment were expensive and time-consuming, and often involve chemicals which can impact on crops, soil quality and water sources.
Weed control is thought to cost New Zealand agriculture at least $1.685 billion a year, according to a study by AgResearch.
Ghamkhar said he considered the challenges farmers faced with weed control on hill country when he wrote the proposal for the project.
"I know how difficult it is to get up there and if this is successful, I think it can do a job which would normally take a farmer two to three days in two to three hours."
He said they wanted to develop something that could be an efficient option for users such as farmers, regional councils and the Department of Conservation.
"We've already spoken with our collaborators in the universities about the lasers that are available that might be suitable. The effectiveness of lasers against plants has been tested overseas before but that was in the lab, and we'll be taking it out in the field to test and see if it works as we have planned."
He hoped to be testing the lasers outside early next year and be testing the lasers on drones as early as August.
"We'll be starting with testing of different types of laser with plants at three different stages of growth in the lab, and from there we will select the best form of laser to see its impacts on the weeds out on a farm."
Ghamkhar said they would be testing the technology on weeds including giant buttercup, yellow bristle grass and winged thistle.
"There are issues we would have to consider such as heat generated by the lasers, and the risk of starting fire, and we'll be very conscious of this particularly where there are dry days or drought conditions. We'll also be looking at using a group of small lasers to direct at the weed, as opposed to one large and powerful laser that might generate more heat."
The project was awarded just under $1 million from the Ministry of Business Innovation and Employment's Endeavour Fund and AgResearch will partner in the project with researchers from the Universities of Auckland and Michigan and NZ-based technology firm Redfern Solutions.
The programme is funded for three years, and if successful could lead to it being commercially developed.