By Amelia Genis
A farmer makes another plan, using drones to spray pests now that the fields are too wet to send in a tractor.
“It’s an exciting business. We are in the infancy of the future,” says Viljee Loubser, who manages the grain and vineyard departments of Fair Cape Dairies.
They bought two drones, mainly for spraying, but he has also used them for foliar fertilisation. “We can’t get the tractors into the fields, and the planes are fully booked.”
Loubser says they were able to book planes for earlier foliar fertilisation but urgently needed to spray against rust fungi in the oats they grow for silage, and the drones came in handy.
They have also used the drones to perform a complete spraying of fungus, lice, broadleaf and grass weed control on wheat.
‘It can’t wait until tomorrow’
“One of the most important lessons of farming is that you have to do what you need to do today. It can’t wait until tomorrow,” says Loubser.
“We realised that if we wait, the weeds become too strong or the chemicals arrive too late to combat the fungi.”
With two drones, they can spray 100 hectares a day. “That’s sufficient for me. It’s actually an emergency, and in an emergency 100ha per day is a lot.”
So far, they have sprayed 1,000 hectares. “It’s going well, it’s fast, it works nicely.”
Loubser bought the drones, plus a generator to charge the batteries, batteries, tanks and spraying units, from Precision Agricultural Systems (PACSys) in KwaZulu-Natal. PACSys trained his team and the next day they started spraying. “We’ve been spraying every day since then. We’ve been blessed with calm wind days for the past two weeks. The drones work like a bomb.”
‘More effective than an airplane’
Loubser says the drones work like helicopters. They fly at a height of 3.5 metres and “blow the pesticide towards the plant”. By agitating the plants so that the pesticide moves through them, they provide better coverage than a plane, but not as good as a tractor sprayer.
He attributes this to the fact that the drone sprayer uses only 30 litres of water per hectare, while a tractor sprayer uses 150 litres/ha. “I also think evaporation is less with a drone.”
The drones practically work for free, and Loubser believes they will be used more in the future. One drawback is that the batteries need to be replaced after a certain number of charges, but they have a diesel generator on the field so they can charge the batteries continuously. Labour is the same as with a tractor sprayer or plane.
Loubser calculated that the batteries cost R20 per hectare over their lifetime, and the fuel for the generator is R5/ha. “An airplane costs around R250/ha, and you can’t even get it anyway.”
Bollworm
Loubser thinks the drones will work well when they need to spray for bollworm at the end of the season. “We usually weigh the decision for a long time because even though the spray material is cheap, the airplane costs are very high, and we don’t want to drive tractors over the wheat during that time. With the drones, we can decide faster.”
Another advantage of using drones for fall armyworm spraying is that evaporation is significantly less than with planes. This means they can spray with the drones all day, whereas with planes they can only spray in the morning.
Works for fertilisers too
Loubser says foliar fertilisation can also be done with the drones. “They can carry 50kg of fertiliser. In the case of urea containing 40% nitrogen, with 50 kg/ha you can provide 20kg of nitrogen, which is not bad for foliar fertilisation.”
He applied 120kg of fertiliser per hectare and could handle 40-50ha a day. It takes six-and-a-half minutes to empty and refill a drone sprayer. “These things have to work. When a drone lands, it has to be loaded within a minute.”
To achieve that level of efficiency, a good support system is needed. They have built a trailer to move everything needed to “reload” the drones. The trailer is towed by a quad bike. Their system is also designed to have central points where the batteries are charged and the drones’ tanks are refilled.
Each drone can spray 9m-wide swaths, and Loubser says that if he moves his two drones back and forth they can cover 36 metres of a field. They fly at 20-25km/h.
In addition to the other advantages, he believes damage to other crops is reduced because the drones operate at a low height and provide better control. There is also no wear and tear, and “nothing to oil or grease. You just wipe it with a cloth in the evening and rinse it. All its parts can be easily removed and replaced.”
Loubser believes this is the technology of the future. “The young farmers are very interested in it. I still want to drive a tractor, and they want to fly these things.”
Although they will only see at harvest time how well the drones have controlled diseases and weeds, he can already see that the weeds have been eradicated.
