DRONES IN THE MIST

I was fascinated at the sight of a table full of drones among the local wines and handmade firepits at the 2014 Murrumbateman Field Days. Suddenly these flimsy machines could be owned by individuals, not just used by governments to drop bombs.

I failed to find a real excuse for us to own one, although we examined a lot of possibilities.

A flying camera!

A remote tree inspector!

An electronic sheepdog!

Justin Borevitz enthusiastically brought out his whole lab team in the summer of 2016 to try their drone, which they’d already used to map some of the trees we planted in 2015.

I wasn’t wild about the intense rotor noise, like a whole hive of buzzing wasps, but it was fun to see images from high above on the tiny screen of the controller. The machine was cutting edge at the time, but objectively flimsy (losing one of its rotor blades in a bumpy landing), and the camera needed to be higher resolution to be really useful.

The next experiment was to send it to the limit of its range, to look at some of our tree plots on the other side of the river. This was plausibly a great way to inspect how they were growing, even when the river is in flood (which it wasn’t). It was a little slow and awkward to aim it at a particular seedling in its pink cover, however. It also couldn’t go beyond the top of a hill, of which we have many, because it would lose line of sight.

They also tested the concept of using a drone to move a small mob of sheep. Unfortunately the sheep took no notice of the buzzy, flying thing. They eventually moved, very slowly, with it bouncing frantically on their woolly backs. Our neighbour Andrew, never one for wasting time, showed how quickly a couple of dogs and a runabout could do the same job.

So we went down to the river for a swim, occasionally buzzed by the drone.

Six years later, we finally got another chance to see if a drone could make itself useful. Cropbusters, a team from Cooma, arrived on a foggy morning with their industrial size spray drone and set off to treat our neighbour Andrew’s Bathurst Burr. We watched in fascination as the machine traced its way back and forth across the paddock, zapping each burr like a giant dot-matrix printer. Beforehand, they had sent up a regular mini-drone to make a map that was then downloaded to the big drone to put into action. Mostly the drone was invisible because of the mist.

The big drone carries 15 litres (about 4 US gallons) and can run for 20 minutes between battery changes. It takes two people to run, one operating the remote control, the other exchanging batteries and refilling the chemical tank. They have to have commercial pilot training which is a pretty expensive course.

The big advantage of a drone that we saw is the ability to travel over rough ground and spray accurately without having to drag hoses or backpacks. Helicopters and fixed-wing planes can spray big areas broadcast, but they can’t easily avoid non-target areas, like trees. Even with the best-skilled pilots, they’re a bit all-or-nothing.

We decided to try Cropbusters out on our own blackberries, which have been getting very out of control in the last couple of wet years, particularly on Adnamira. So they turned up early a couple of weeks later, on a much less foggy morning.

It’s very steep country along the edge of Oakey Creek and even worse on the other side of the ridge in Boggy Creek. Frank calls it the “Grand Canyon”. The blackberries have been coming back over and over for decades. Spraying there with heavy backpacks is something everyone wants to avoid. Even though a Quikspray electric wind-up hose reel can pull you back up a steep hill, hand spraying is still an onerous process.

Compared to Andrew’s paddocks full of many small Bathurst Burr plants, however, the large blackberry clumps were quite widely scattered, and the full mapping and transects would have involved a lot of extra flying and returning for batteries. There were also wattles and eucalypts scattered around that I wanted to avoid spraying. So Cropbusters decided it would be more efficient to hand control and direct the drone for each clump. After a few tries using a relayed image from the little mapping drone to the refuelling station at the bottom of the hill they found it easier for the pilot to climb up the hill to direct it more closely, while his partner kept going with the refilling.

I was concerned this meant we were back to someone having to clamber up and down the rocky slope, but he was quite happy dodging about, and pointed out “it’s still much easier than having to carry the chemical on your back”. Which it is.

In particular, it was much easier for me to watch the drone bobbing about the hills getting rid of the blackberry clumps while Dmitry and I collected covers from last year’s tree seedlings on another hill.

Because there were desirable eucalypts and acacias in among the blackberry, they experimented with how close they could drift the spray without affecting them. Again, definitely still better than fixed wing aircraft.

The drone was great overall, but was pretty sensitive to wind, and they had to stop early for that on two of the three days. There were a lot more clumps than I expected, so we didn’t actually complete every single one.

However, we definitely began to catch up on some of the deferred weed control.

And we’re definitely having them come back next year to mop up.

Meanwhile I’m hoping that my friend Jonathan will come from Hall and do some aerial photography. Just waiting for the right sunny, windless, day.