Drones are becoming an important tool for farmers and ranchers across the country. They offer solutions for improved pest scouting, chemical application, and seeding. In the early days of drone utilization in agriculture, the focus was their ability to carry multiple cameras. With the assistance of image processing software, they could detect pasture forage availability and forage quality — mostly in single-species stands — along with weeds and diseases. As drone technology continues to improve, they are now able to do more than carry a camera; they can be used as tools for pasture improvements, especially in areas that have historically been off-limits to anything more than backpack sprayers and hand seeders due to difficult terrain.

We have begun to research the challenges to seeding and applying herbicide to small pastures and steep and variable terrain. As the payload a drone can carry improves, it will quickly become a tool for pasture fertility as well. Even for pastures on uniform terrain that may be divided into smaller paddocks for management-intensive grazing, drones can be a better fit than many commercial spreaders and seeders.

The Federal Aviation Administration (FAA) classifies any drone with an operating weight greater than 0.55 pounds as a commercial drone, which must be registered with the FAA. The registration number must be displayed on the drone. Registration applications can be completed online if the drone’s maximum weight is less than 55 pounds.

When the drone weighs more than 55 pounds, the registration process requires additional validation to ensure the purchaser of the drone is the same person registering it. This validation is done through a notary. To fly a commercial drone for any purpose, one must obtain the FAA Part 107 Certificate, and as part of this process, you will need to take and pass the Unmanned Aircraft General-Small (UAG) knowledge test. If you plan to apply pesticides, you will also need a Part 137 Certificate, which will allow you to apply pesticides using a drone, or apply pesticides using drones while under the direct supervision of a person who holds this certificate.

In most states, this is not the only step it is required to complete to be able to apply pesticides. Drones are considered aerial applicators and must follow the pesticide licensing rules in your state. Two important rules that can cause problems with some pasture applications is that you must be able to see your drone visually at all times and you must have a pilot and spotter present when operating the drone.

Use a UTV

When using a drone on uneven terrain, several challenges arise, whether spreading a dry product or applying a pesticide. One is that remote pastures must be accessed with the equipment to tender the drone. While this is often done from a large trailer, a tender could also be built on a utility terrain vehicle (UTV).

When spraying or spreading with a drone, the battery life usually ranges from 15 to 30 minutes, with batteries needing to be changed each time the drone is refilled. A 240-volt generator can be carried on the UTV to recharge the batteries. Depending on the UTV payload, you can usually also carry 50 to 100 gallons of herbicide mixture. Using the UTV to access hard-to-reach areas while keeping a large tender to refill it in an easier-to-reach area can allow for better access to many pastures.

When flying over uneven terrain or around large woody invasive species, we have experienced challenges with the collision avoidance software. The software has performed well in avoiding collisions for us, but it has required us to fly in manual mode or repeatedly confirm our intention to continue. For steep terrain such as reclaimed strip mine ground, the terrain avoidance worked best when we flew up and down the slope. For less steep terrain, once a pasture boundary is created, the drone will plan its own most efficient flight path.

Seed-to-soil contact

Drone seeding poses one key issue that is shared among all renovation methods that don’t facilitate good seed-to-soil contact. Therefore, it is critical to select species that can be spread on the soil surface and still germinate. Germination can be improved by frost seeding, which leverages soil freezing and thawing to create seed-to-soil contact. Another option is to seed the pasture and allow the livestock to walk the seed in. This can look like using high stocking rates of 30 cow-calf pairs per acre for a day or 30 pairs per 6 acres for a week to incorporate the seed. Livestock need to be removed after a week so that they do not damage the newly germinating plants and should not be allowed to graze the renovated area until the new seeding is 8 to 12 inches tall.

After seed selection, the next step is to set up your drone. Based on your seed size and seeding rate, you will need the correct hopper gate. Low seeding rates of clovers will require a small hopper gate, whereas high seeding rates or large seeds — such as annual cereal grains — require a large hopper gate.

Initial calibrations are performed using a drone controller to bench-test how many pounds of seed come out of the hopper per minute. Pattern testing can also be used to make sure your swath width is correct for the seed you are using. When conducting a pattern test, use boxes or totes that are tall enough to prevent seeds from bouncing out. The seeding pattern of a red and white clover mix differs significantly from that of an annual ryegrass and orchard grass mix, as demonstrated in the figure.

Our seeding rate goal for the clover mix was 5 pounds per acre, while the grass mix seeding rate goal was 6 pounds per acre. The clover mix had a much more uniform spread pattern for a 20-foot swath than the grass mix; the grass mix had a much higher seeding rate in the center 10 feet. When possible, double spread the pasture to improve the uniformity of a grass seeding, either by splitting the swaths or by spreading two passes that are perpendicular to each other. When seeding species with different spreading characteristics, it is best to not mix them together but to spread them separately.

Drone seeding can be done while cattle are in the pasture. They tend to move away from the drone at first but then follow it around the pasture and don’t stampede.

Weeds, insects, and diseases

The first step in any pesticide application is to scout your pastures and identify exactly what weeds, insects, or diseases you need to control. The second step is to read the label on the product you plan to use. For drone applications, you must follow the aerial application section of this label. There, you will find important guidance on how to apply the product.

A few unique requirements you may see are that many products have restrictions on boom width based on the wing or rotor width. Most products also contain a minimum spray volume that can be used, but often recommend higher rates for better coverage. Labels also specify the droplet size and recommend additional adjuvants to minimize drift and enhance pesticide deposition.

Woody invasive species can be challenging to control with drone applications. Herbicides often fall on the top leaves but don’t reach the center of the plant. For large trees or bushes, it might be beneficial to fly around them, spraying the sides as well. The downforce from the drone can help shake the plant and push the herbicide into the center; however, these woody perennials may require multiple years of application to kill them.

One method to improve drone pesticide application is the use of water-sensitive paper to ensure that your herbicide reaches its target. This paper turns color when exposed to water. Wear gloves so that the moisture on your hands does not change the color and use a paper clip to fasten them to plant leaves. Then, make an application and look for the color change. If no color change is apparent, your application needs to be adjusted.

As drone technology continues to advance, it has potential to be a more widely adopted tool for pasture management. Drone use may fit some pastures better than row-crop equipment and offers a strategy that is safer than tractors and utility vehicles.

This article appeared in the August/September 2025 issue of Hay & Forage Grower on page 30.

Not a subscriber? Click to get the print magazine.