Agricultural drones are becoming more common in farming practice in order to drive efficiencies and gain better insight into crop status. This is yet another stage in the agricultural road of progress over the last 100 years. The idea of controlling an aircraft remotely would have been an extremely novel thought a century ago, but today almost every industry has found good use of Unmanned Aerial Vehicles (UAV’s). Drones are the most common type of UAV.

What is a drone?

A drone is defined as a “remote-controlled, pilotless aircraft or small flying device”. Industries or high usage activities which have successfully used drone technology are the military (fly into and provide visual feedback of high-risk areas), filming and photography (to create dramatic views above specific locations or activities), the health sector (to deliver blood and much-needed medical supplies to areas which were previously unreachable and, of late, as a leisure interest. Even companies like Amazon have also made use of drone technology to deliver packages to customers.

In recent years, sectors like Agriculture have also started making use of this technology and, since its inception, the industry has received the technology with open arms. The bulk of this article will focus on Drone Surveying (to view crops) and Drone Spraying (chemical application). Across the world farmers are also using agricultural drones for seed planting, irrigation monitoring, and real-time livestock management. Seed planting activities are still in their infancy.

Drone Surveying

Using high-resolution cameras and infrared sensors, an agricultural drone can create a picture of infield crop conditions and crop progress. The premise of drone surveying is the same as with satellite crop monitoring, but it has the added advantage of monitoring in real time. Satellite monitoring does not occur in actual time, as the satellite takes pictures over a specific time span, and usually does this once within a 24-hour period. Although helpful, the lag in decision-making time may impact overall results. Farmers can now decide on the fly which, in the long run, can make a tremendous difference. Satellite images have one major disadvantage – cloud cover can block the satellite from taking images. It’s possible to get no photos of your farm for weeks in rainy seasons. Drone overcome this by capturing images below cloud cover.

Drone surveying is also useful in getting a clearer picture of an entire field, with a case study by Stephen Pennells from Hygrotech in 2018 cited as an example. During inspections, the farmer and the team determined a certain yield potential of his field given the information to their disposal. Soon after, the farmer purchased a drone for recreational purposes, but carried out a flyover of his fields, with a subsequent inspection revealing that the team’s initial predictions were inaccurate. On the pictures taken, there was a 12 – 15ha piece of land on which there was no crop. The infield inspection revealed that the section was infested with gerbils, which love feeding on young seedlings.

Although this was an example where the farmer could not act immediately to improve the situation, the information helped with planning for the next season.

Drone Spraying (Chemical Application)

Traditionally farmers have made use of boom sprayers and high-rise sprayers to apply crop chemicals. ‘High boy’ sprayers have also become extremely popular later in a season when it is difficult for traditional sprayers to enter the field. The fundamental problem with these high boy sprayers is the high cost of the machines, which has made it impossible to implement across the board in farms across Africa. This means that most farmers are still making use of contracted aerial crop sprayers during these times in the season, as it is still cheaper than buying and operating one of these high boy sprayers.

These contractors, however, are highly affected by weather and cannot always spray when the time comes, leading to high doses of herbicides and pesticides being applied long after the correct time for application. This impacts the effectiveness of chemicals applied. Expenditure on chemicals is high, so it is crucial for farmers to make use of these substances in the most effective way possible.

Drone herbicide and pesticide application is still a new term in Africa, but it seems to solve the above problems:

1. This chemical application by drones is a lot cheaper than traditional high boy sprayers and does not require the farmer to be or to hire in a traditional commercial aircraft crop sprayer. Only a special drone licence is required to control these drones with the aid of flight planning software.
2. Chemical spraying drones also allow a farmer to spray more hectares within a day than was originally possible.
3. Farmers can carry out their applications on time, as there is no waiting on a contractor before applying herbicides or pesticides.

Chemical Spraying Issues with Drone Technology

Spray Drift

As with all new developments, there are some concerns that do warrant attention. Most of the concerns have to do with spray drift, as this can be detrimental if some chemicals land on non-target crops. Spray drift occurs when the wind carries away molecules from the intended area. This becomes more of an issue when dealing with small spray particle sizes. With drone spraying, most drones have a small payload, and thus the amount of water applied per hectare is lower than with traditional methods. With these low water volumes, the particle sizing is also lower and thus more susceptible to drift. New nozzle technology and new products, like Mist Control and Interlock (drift retardants which are added to tank mixtures) are being proposed to control drift.

Statutory Regulations

Another issue under the spotlight are the regulations regarding the use of agricultural drones. Although rulings in the United States allow for this use, most countries worldwide are still lagging with their regulations. It does, however, appear that the pros outweigh the cons of using drones in agriculture at this stage.

Unitrans Africa Precision Agriculture Services

Unitrans Africa is a leader in precision agriculture technology in Africa. They have built up a large footprint in Africa owing to expertise and reputation for constant agricultural innovation. They now have a solid base of agricultural operations in many African countries such as Malawi, Zambia, Tanzania and Mozambique.

Together with other precision agriculture practices, which Unitrans Africa offers (soil sampling, VRA fertiliser application, field levelling and yield mapping), drone surveying may be part of the process to address all aspects of your farming initiatives, in order to reduce costs and increase yields.

Find out more about Unitrans Africa’s values of innovation, honesty, excellence, unity, safety and constancy, as well as their ability to provide comprehensive contributions to farming operations by contacting them via email.