Drones in Agriculture
Fact Sheet | Drones in Agriculture
THE BASICS
Drones are a promising addition to agriculture, with the ability to perform jobs that are otherwise impossible or very expensive. However, they are also a technology that is rapidly evolving. While some farmers are using drones, an increasing number of companies offer drone services to farmers.
In general, there are two types of drones, categorized by the task they perform: smaller, less expensive drones for mapping; and larger, more expensive drones for applying materials (pesticides, cover crop seed, etc.).
The basic process for using drones is:
1) Gather field data - Map the field with a remote sensing drone or existing maps.
2) Analyze field data - Import the field data gathered by the drone into a computer program and analyze it for use in making decisions. Or, use the existing maps to plan the route of the application drone.
3) Create a flight map for the application drone.
4) Apply material with an application drone.
REGULATIONS
Before engaging in any of these operations, be aware that all agricultural drones are regulated by the FAA. It is important for farmers who are considering doing their own field work to understand the required regulations, which continue to change rapidly.
• Drones under 55 pounds - A drone under 55 pounds that is used for fun is NOT regulated by the FAA, but any drone that is used for business (like farming) DOES fall under FAA regulations. Typically, drones under 55 pounds are those that are used for mapping/sensing. Operators of mapping drones need a Part 107 certification from the FAA. This process is similar to obtaining a pesticide applicator’s license - get the study book, study, take the test, file paperwork with the FAA, and keep up with continuing education credits.
• Drones over 55 pounds - Drones that weigh over 55 pounds are typically used for applying materials. They require an oversize frame certificate from the FAA. This is a more involved process that requires more paperwork, more time for FAA approval, and a doctor’s note certifying the operator’s physical fitness.
• Drones applying materials - There are additional licenses required by the FAA for operators applying materials. According to the FAA, a drone operator “dispensing any other substance intended for plant nourishment, soil treatment, propagation of plant life, or pest control” needs a Part 137 exemption.
• All drones must be registered with the FAA.
USING DRONES TO MAP
Cameras
Where as applying materials with drones is new and there are constantly new developments, crop mapping by satellite or airplane has been developing for more than 20 years. As a result, there is good existing information on the types of cameras and the programs used to interpret the data into usable field maps. A mapping drone can be fitted with a variety of camera types. Each type of camera ‘sees’ something different (see the table below). Camera models will be more or less expensive based on their resolution. For example, image quality could vary between one square inch per pixel to one square foot per pixel.
Here are images taken by different cameras of the same field where a nitrogen trial is being run. On the left is an image from an RGB camera, and on the right the image from an NDVI camera. Notice how the light spots, which are plants low in nitrogen, show up more clearly in the NDVI image, but the N-stressed plants can also be identified in the RBG image.
Source - University of Delaware, Types of Drones for Field Crop Production, by Jarrod Miller and James Adkins, Published January 19, 2018
Making the Map
Buying and flying a drone is the glamorous part, but that is only 10% of the work. The other 90% is manipulating the gathered data to make accurate maps that provide actionable information. A drone operator might fly a 10 acre field in 30 minutes, but then spend three hours on the computer turning that data into a map, though with more experience that analyzing time might be reduced to 30 minutes. It takes training and experience to make each kind of map, and several maps may be made from a single drone flight, such as crop stand count, soil moisture, and nitrogen-stress.
Typically after a mapping flight, a drone operator will upload the data to the cloud in order to use big computing power to analyze it. A farmer’s computer may not have the power needed to analyze the flight data, and farmers in rural areas may not have the internet connection needed to upload 20GB of data to the cloud. Farmers investigating doing their own drone work should consider this.
Flying a drone and making a map are two different skills, and most drone pilots are not agronomists. The pilot may make a field map for a farmer based on a flight which could be used to guide an application-drone, but often an agronomist will be needed to interpret the map and advise on management decisions.
To learn more, search the web for commercial mapping companies in your area.
USING DRONES TO APPLY MATERIALS
Applying materials with drones is a newer practice, and the technology of drone-application is advancing rapidly, as are the capabilities of application drones.
Applying Pesticides and Fertilizers
Drones have several advantages over ground sprayers:
Field Access Drones can fly and apply regardless of soil moisture which is a huge advantage over ground sprayers.
Precision Application Unlike airplanes or ground sprayers, if a farmer has a 120 acre field with a pest problem in only three acres - drones can apply on just those three acres.
Minimized Drift Whereas ground sprayers have to drive with the crop rows or on tramlines, drones can follow any pattern in order to minimize drift.
Considerations when spraying:
Droplet Placement The goal is to get small droplets under the crop canopy to land on the underside of leaves. Droplets above the canopy will quickly evaporate while droplets under the canopy persist longer and are more effective.
Spray Volume When tank-mixing multiple materials, do a jar test to check for compatibility of your materials, even if they have been mixed previously with a ground sprayer. Materials can act differently when drone-applied because drones do not have agitators, they use much higher concentrations of materials, and they use lower volume pumps.
Seeding cover crops It is increasingly common to use drones to underseed cover crops into established cash crops. For example, farmers are drone-planting red clover into winter and spring wheat and other small grains. They are also planting many cover crops into established corn, such as clover, turnip, radish, rye, or mixes. Drone-seeding of cover crops is new and evolving, with new experience, techniques, and capabilities every season.
WORKING WITH A DRONE COMPANY
There are new drone companies and pilots entering the industry all the time, each with varying levels of experience and capabilities. When choosing a drone company, consider:
• How many acres has the pilot sprayed and how many acres do they spray per season? For example, 800 acres is not a lot of experience for drone spraying. A rough rule of thumb from one drone professional is that drone-spraying between 3,000 to 5,000 acres per season is enough for a drone pilot to know what they are doing.
• How often has the company sprayed the crop under consideration and do they have experience with the chosen material?
• Is the pilot being contacted early enough in the season? Drone pilots are busy. Farmers can’t expect to call them three days before they want the drone flight, so call at least one month in advance.
FINANCIAL CONSIDERATIONS
As a rule of thumb, drone-application prices should be similar to the price of ground application.
The price per acre will rise as the volume or weight applied increases, the distance from the drone pilot’s base increases, or the number of obstacles in a field increases.
Customers often receive a price break when they contract for multiple applications. This is because the company has to make a field map whether they apply once or three times in the season, and they can often use the same field map for several applications.
TAKE AWAY
Unless a farmer enjoys learning technology and working on computers, it generally makes more sense to hire a drone company to make maps. They have more experience and access to better algorithms so their maps are often more accurate.
Research reported in this publication was supported by The Organic Center and the Foundation for Food & Agriculture Research under award number TOCFFAR-EXT-002. The content of this publication is solely the responsibility of the authors and does not necessarily represent the official views of The Organic Center and the Foundation for Food & Agriculture Research.