New AG International NOV/DEC 2020
On the fertilizer front, Arthur Erickson, CEO of Texas-based Hylio, notes the vast majority of commercially available crop spraying drones, including those from Hylio, have capacities ranging between two to six U.S. gallons. “Thus, most of the platforms are great for applications where rates of three U.S. gallons per acre or fewer are used, as is the case for many pesticides and micronutrients ... [but] less appealing for the relatively heavier dosages that are typically associated with NPK fertilizers, [where] producers may be applying dozens to hundreds of pounds of product per acre.”
So, while drones aren’t currently ready to replace traditional large-scale fertilization methods, they are already particularly useful for intelligent spot spraying of targeted areas within larger fields, and for servicing hard to reach areas that have obstacles that would otherwise be prohibitive for traditional aerial or terrestrial equipment.
However, Erickson adds that innovative developments in the fertilizer space that could significantly reduce the necessary amount of fertilizer per acre might allow drones to be viable for large-scale application.
Indeed, back in 2017, Rauch – a German manufacturer of fertilizer spreaders – announced a project to develop a large fertilizer-spreading drone with Germany-based Agronator. In 2021, Agronator will market drones 4.6 metres (m) across with payloads of 35 kilograms (kg) for applying crop protection products and seeds/fertilizer.
Application details Drone systems already on the market capable of fertilizer dispersal differ slightly in typical height and speed of application above the crop and, as mentioned, size of tank or hopper. Crop type and weather are obviously factors that affect height, but Melanie Wu, deputy general manager at China-based RLF (Rural Liquid Fertilizers) reports that drones in China generally apply fertilizer between one and 1.5 m above the crop, with single-rotor models flying slightly higher than multi-rotor.
“Generally, about 0.8 to one kg of liquid per mu (a Chinese unit of measurement equal to 0.16 acres or 667 m2) is used,” notes Wu, who adds that in her experience, liquid fertilizers are generally preferred, as powder products can block dispersal mechanisms.
However, Eric Acquah, owner of Ghana-based AcquahMeyer (AM) Dronetech, says that while in the past he had only drones capable of liquid fertilizer delivery, “we have a new drone that can do powder and solid application. Our 10-litre (L) [system] sprays 10 acres per hour (ac/hr) and the 15-L sprays 13.5 ac/hr.” AM drones usually spray between a metre or two above the crop and Acquah explains that because drone input application is still relatively new, most product-makers do not have drone spraying height on the product label. He reports that in 2019, he and his team completed the first drone calibration for some products registered in Ghana for one of the biggest manufacturers of pesticides and fertilizer in the world.
China-based DJI Agriculture’s T16 drone can apply liquid or solid fertilizer, usually 2.5 to three m over the crop at a speed of five or six metres per second. Photo: DJI Agriculture
The system offered by China-based DJI Agriculture can also apply liquid or solid fertilizer, usually 2.5 to three m over the crop at a speed of five or six metres per second (m/s). The company’s AGRAS T16 spreading system has a maximum spray rate of 4.8 L/minute.
“The MG-1P drone series can carry a 10 L spray tank, while the T16 can carry a 16 L or 20 L spray tank,” explains Ronnie Liu, senior marketing manager with DJI. “The MG series sprays 14.8 ac/hr, while the T16 can spray 24.7 ac/hr for a regular-shaped field.”
Hylio’s drones apply liquid fertilizer or other inputs typically 1.8 to three m above the crop at a rate of one gallon per acre, including downtime for refill between flights. Their smallest model, the AG-110, has a 2.9-gallon tank and can cover about 12 ac/h with the largest model, the AG-122, holding 5.7 gallons and covering about 27 to 30 ac/hr.
Costs Drone application of fertilizer can offer farmers savings in a variety of ways, obviously foremost through avoiding the labour, fuel usage and other operational costs of conventional application methods. Drones can also enable farmers to use less product, especially when the application of fertilizer or another input is very targeted (however, the operator must be quite skilled or the programming of the automatic flight path very good).
Texas (U.S.)-based Hylio’s drones apply liquid fertilizer or other inputs typically 1.8 to three m above the crop at a rate of one gallon per acre, including downtime for refill between flights. Photo: Hylio
Every farmer’s situation is different, and of course it takes time to fully implement and gain the maximum benefits from any new technology. ROI of any technology must therefore factor in implementation time as well as specific existing costs versus the costs of the new system. Drone ROI calculations must also encompass other uses the drone is involved with beyond fertilizer application, such as crop protection product spraying, fertilizer requirement mapping, and crop scouting for insect or disease presence.
Yes, in addition to offering the capacity to apply it, major ag drone firms also presently offer farmers the service of mapping fields for fertilization requirements. Of course, drones equipped to apply fertilizer and other inputs are much larger than drones that simply map a field – these are typically very small units equipped with only cameras and/or sensors. Mapping, like input application by drone, can be done manually or autonomously using GPS-based programming.
Farmers must also decide whether it’s more cost-effective to use a custom drone application service (if it’s available in their location) or to operate the drone themselves. At least one academic in the U.S. is helping farmers build their piloting skills, should they choose to go that route. Tennessee State University Associate Professor Jason de Koff has developed a training program for drone operation which includes guidance for how to gain maximum financial and environmental benefits from the technology. With graduate student Priya Saini, he has also created documents on drone and sensor options and costs, and how to capture and analyze drone images.
For his part, Erikson at Hylio has “substantial confirmation” from his own team operation of drones for farmers and from customer feedback, that both capital and operating costs of drone use “are far lower than their traditional counterparts: terrestrial boom sprayer and plane/helicopter crop dusters.”
Liu is in agreement that drones are cheaper to use than tractors for application of fertilizer and more in some situations. DJI has calculated that in some Asian countries for example, ROI of drone use can be achieved in as little as a month. In addition, in some countries such as China, drones’ costs are subsidized to encourage their use.
And, as is the norm with new technologies, capital and operational costs of drones in farming will continue to fall.
“The market competition is stiff, the price is getting lower and lower, and service fees are decreasing,” says Wu. She adds that at this point in time, some drone-flying companies and drone manufacturers have now partnered with pesticide and fertilizer companies to introduce competitive packages.
Challenges There are several challenges in drone application of fertilizer. The weather must be amenable and users must ensure that what they are doing aligns with existing laws. Countries differ in their drone regulations and farming drones are often lumped in with recreational drones in the legal sphere. Recreational and ag drones commonly have a maximum operating distance of 500 m from the operator/base, with the operator needing to have line of sight at all times.
Erikson adds, however, that because crop treatment drones have heavy payloads and you wouldn’t want to fly them large distances, those restrictions are typically not an issue. Wu adds that no matter the location, you should always obtain local flight clearance. Operators themselves must also have the appropriate certifications.
In terms of drone design, along with other traits, their abilities to detect obstacles and avoid them is evolving. The DJI T16, for example, has a radar system with forward and backward obstacle avoidance and a horizontal field of view of 100 degrees, double that of previous DJI ag drones. It can also detect the angle of a slope and adjust to it automatically.
China-based RLF drones in China generally apply fertilizer between one and 1.5 m above the crop, with single-rotor models flying slightly higher than multi-rotor. Photo: RLF
Acquah lists the biggest technological limitation at this point to using drones to be flying time. “There are no batteries on the market that can give us a flying time of more than 15 minutes,” he says, “so you have to keep changing the battery set while spraying.”
And although, as mentioned, larger capacity is being examined for fertilizer application by drone, Liu says heavy payloads may face restrictions in some areas. “Regulations are different from country to country and sometimes they’re the biggest challenge for us to expand the drone market,” she observes. “All we can do is to try our best to do experiments, provide better solutions and convince the market.”
With the costs decreasing and uses expanding for drones – into harvest, beneficial insect dispersal and more – it’s a good bet the market won’t take too much convincing that crop care from the air is here to stay.
CNH Industrial N.V. has completed its acquisition of a minority stake in Zasso Group AG, a global specialist in non-chemical weed and invasive plant management solutions using electrical power.
Zasso’s patented Electroherb solutions enable targeted, chemical-free weed control using an electrical current. This technology can also be employed in urban weed management situations. Zasso claims Electroherb is as effective and efficient as standard chemical herbicides, does not have to contend with growing developed plant chemical resistance, and delivers social and environmental benefits.
Zasso Group, headquartered in Zug, Switzerland, was founded in 2016 and joined CNH Industrial’s AGXTEND platform in January 2019. AGXTEND is CNH Industrial’s leading platform for innovative technologies in the agricultural sector, and commercializes Zasso’s tractor-based electric weeding solutions under the XPOWERTM product name.
CNH Industrial is a global leader in the capital goods sector, including tractors and agricultural machinery, with over US$28 billion in consolidated revenues and 63,000 employees in 2019.