Farmers donât buy spraying drones or hire drone spraying services because of the environmental benefits, of course. They donât need to justify the use of them. They sign on the dotted line for higher profits.
Not long ago I had the opportunity to spend 90 minutes with Arthur Erickson of Hylio, a North American manufacturer of agricultural spraying drones. The two episodes of the podcast that resulted tell a fascinating story of agricultural technical transformation.
In the first episode, Erickson lays out the basics. Two of Hylioâs biggest drones, the AG-272 with its 14-foot tip-to-tip diameter can carry 400 pounds of agricultural inputs â fertilizer, herbicides, pesticides and fungicides â between them, and can cover as much acreage in a day as a $700,000 modern spraying tractor, yet all-in cost about $200,000. Even a second-hand tractor which covers less ground per hour will cost likely $300,000.
And modern tractors take well over a year to deliver after ordering, can have upwards of twenty miles of cabling, and require sophisticated computer-analysis and wrenching when things go wrong. When something goes wrong, they can be out of service for weeks. Despite massive demand, Hylioâs drones have a few months for delivery times, and are incredibly mechanically simple, so very easy for farmers to wrench in the fields.
Agricultural drones are pervasive, as I discovered after the discussion. Ericksonâs guess was 15% usage by the two million farms in the US, either as a service or with direct ownership, but statistics suggest current usage is a lot closer to 100% than not, with 75% of farmers surveyed in 2018 having used or planning to use drones.
Most of that usage is in surveying drones, and usually fixed wing drones. With sensor packages that include high-resolution cameras and multispectral sensors that can spot temperature gradients and degrees of moisture, and SaaS platforms like Pix4d that stitch together data from any sensor set to provide input insights and KML files for precision agriculture, farmers know exactly where to put how much product.
But itâs tough to get precision without drones. Aerial crop sprayers that use fixed wing or rotorcraft vehicles spray a lot of inputs very quickly, but lots of it gets blown off the fields and over nearby roads, ditches, ponds, and the wrong fields. And they have to pull up short or come in late when wires cross the ends of fields or poles are sticking up. As a result, a great deal of inputs donât do what they are supposed to do, nourish crops or kill insects or fungus.
Running tractors across taller crops crushes a lot of them, and it can be tough to get into corners and around obstacles to get good coverage. And you often canât run tractors in wet fields when fungus is blooming because theyâll get stuck or rip up the ground too much.
Agricultural spraying drones, on the other hand, put 400 pounds of down pressure on inputs as they fly 15 feet above crops, aerosolizing inputs and pushing them in among the plants and to the ground, providing much better coverage. And obviously they donât care about muddy fields at all, allowing early fungicidal application with lower volumes and greater efficacy. Per Erickson, an upcoming peer-reviewed report will likely show 30% to 50% reduction in volumes of inputs to achieve the same agricultural harvests, a massive saving.
And tractor usage is a problem with more than crushed crops and ripped up fields. Soil compaction is a major problem. Erickson suggested 3% to 10% benefits from avoiding soil compaction, but studies show 9% to 55% crop reductions from it. Obviously drones buzzing lightly through the air donât compact the soil at all.
Of course, the drone that weighs perhaps 150 pounds that is carrying 200 pounds of inputs is also sipping at electricity while the multiton tractors and aerial sprayers are pounding back the diesel and avgas. The costs of operation are vastly lower, and the benefits of using decarbonizing electricity to power spraying instead of fossil fuels is a big advantage.
But the advantages are much bigger than just saving direct CO2 emissions, the subject of much of the second half of the discussion.
That 30% to 50% reduction in inputs and much lower inputs being wasted in adjacent areas and water ways is big. While the major annual post-harvest fertilization is done with tractors as it often involves hundreds of pounds of fertilizer per acre, the subsequent 4-5 passes being vastly more efficient means that especially ammonia-based fertilizers are reduced. That has two benefits. The first is that ammonia is currently made with natural gas or coal derived hydrogen, with CO2e emissions of 8 to 35 times the mass of the hydrogen, resulting in best case around 8 times the mass of ammonia. Thatâs a big climate problem.
But ammonia-based fertilizers applied to fields split out the hydrogen and nitrogen in the ammonia in a chemical reaction, leaving most of the nitrogen fertilizing the crops, but turning a bunch of the rest of it into nitrous oxide with a global warming potential 265 times that of CO2. And nitrous oxide, unlike methane, persists in the atmosphere for a long time. That turns the 8 pounds of CO2e per pound of fertilizer into more like 11 pounds.
30% to 50% reductions in passes across the field with ammonia-based fertilizers has a big climate benefit, as that vector is one of the biggest agricultural inputs to climate change.
But phosphates, another key input, have issues as well. When they run off of fields or simply land in waterways due to over spraying, they accumulate downstream in ponds and lakes, and can cause algal blooms that suck the oxygen from the water, kill aquatic life, and leave stinking masses of rotting algae in recreational and residential water bodies.
Farmers donât buy spraying drones or hire drone spraying services because of the environmental benefits, of course. They donât need to justify the use of them. They sign on the dotted line for more crops, lower costs of operation, and lower costs of inputs, all things which maximize their bottom line. Hylio doesnât bother to tout the environmental benefits, and Erickson is quick to downplay any suggestion that his ag drones are carbon neutral or environmentally inert, although his concerns about battery production are somewhat overstated in my opinion.
The conversation was great, and it was good comparing and contrasting with other drone-oriented firms like Grant Canaryâs DroneSeed and Kaitlyn Albertoli and Vikhyat Chaudhryâs Buzz Solutions, both of which Iâd spent time talking to in the past couple of years as I looked at the disruptive use of drone-based solutions to accelerate climate remediation and improve grid resilience. Erickson considers DroneSeed to be the grandfather in the American ag drone space, having paved the way for heavy lift drones flying large payloads autonomously over rural areas.
Written by Michael Barnard | 23 March 2023
