It’s well-known that unmanned aerial aircraft are playing increasingly important roles in farm management. Drones are conducting aerial mapping surveys to establish more precise land boundaries and to assess disease and pest damage to crop yields. Less well known is the expanding role of drones in crop harvesting. Two countries are in the forefront of this effort: Israel and Malaysia.
In Israel, the technology firm Tevel is assisting farmers to pick their apples with an entire fleet of fully automated drones. The drones can hover near each apple, and using sensor technology, determine if it’s ripe. If it is, the apple is “picked” with the drone’s metallic arm and deposited in a robotic wheelbarrow that follows the unmanned aircraft as they fly along each row.
In Malaysia the “drones” are actually long metal poles attached like a jetpack around the arms and shoulders of human pickers forming a kind of “exoskeleton” that allows them to reach the heights of 40-foot high palm trees and pick the fronds and their fruit, as needed. Some pickers employ ground-level sensor technology to detect the status of individual trees and the ripeness of their fruit. Pickers no longer have to risk life and limb to scale the trees themselves, and they can move far more quickly from tree to tree.
By slashing the time needed for cultivation, the cost savings in both cases are enormous. A human apple picker might take an hour to gather 50 lbs of fruit; a fruit-picking drone can collect eight times that amount, surveys show. The drones also utilize advanced data analytics to identify and record unripe fruits and automatically send the drones back to the fields to ensure that no ripe apple remains unpicked.
In addition to speeding the harvest, drones can greatly reduce farm labor costs. In both countries, persistent labor shortages have left many farmers vulnerable to rotting fruit and have driven up wages. Farmers must recruit seasonal workers, sometimes from abroad, and then pay for their travel, food and lodging, in addition to their wages. With drones, farmers can dispense with human pickers altogether and can also set their drones loose at night, further accelerating the cultivation rate.
For all their promise and proven early potential, apple-picking drones do face some operational constraints. The most obvious is the limited time drones can stay airborne – about 15-20 minutes – before their batteries need recharging. Another challenge with apples is to ensure that drones don’t bruise the fruit during the automated picking. The drone’s picking arm must gently hold and twist the fruit 45 degrees in one direction to snap it free, then just as gently deposit it into a container bin. Another design option is simply to vacuum the fruit directly into the bin. Invariably, some apples do get damaged during drone picking but the numbers are relatively small – far less than the average 10%-15% loss rate from fruit simply left to rot unpicked, field surveys show.
In Malaysia, drone designers haven’t yet figured out how to make the fruit picking process completely unmanned. For now, drones fly over the terrain and identify palm trees and fruit ripe for cultivation as well as those damaged by disease and pests of various kinds. Pickers can avoid damaged areas and concentrate their efforts on areas where the yield is healthy. With their extended cutting poles and sensors, the pickers’ cultivation rate is much faster, but the harvest still requires human labor. Moreover, their wearable exo-skeletons aren’t cheap; only large farm owners can afford to purchase them and maximize savings from their use.
Another problem is the terrain. Palm trees vary in height and are planted on vast undulating fields filled with snakes and scorpions that make even technology-enhanced picking unfeasible. In some cases, pickers will still have to scale the trees the old-fashioned way, slowly and with great caution.
Could drones one day fully automate the palm cultivation process? Not any time soon, experts say. Cutting down the palm fronds and fruit, which can grow in clusters weighing as much as 30-50 pounds, typically requires heavy tools, a sickle, and sometimes a saw or chisel. Still, some countries outside of Asia have begun experimenting with vegetable harvesting drones that wield small cutting tools. With improved technology, palm fruit harvesting via drone in Malaysia may not be as far off as it seems.