… and, maybe, when not to?

For those farmers and agriculture professionals still thinking of whether or not to choose drone technology to replace traditional crop spraying methods, the article below has some pointers on situations that are better suited for drone-based crop spraying, while others may favour helicopters.

We hope find the advice – which first appeared on Agfax – valuable.

Using drones for crop protection application is an exciting new technology for growers and ag retailers alike, but it’s not a blanket solution for every field or farmer.

Here are five things to consider before heading to the field:

Topography

Topography is what can make drone application a better option than ground or plane spraying. Drones are more efficient and can provide better coverage than plane or ground spraying in hilly, oddly shaped fields.

“If your plane applicator is having to dip up and down and start and stop, the drone is going to work better,” Josh Coffing of Ceres Solutions says.

They are also a good solution for fields near waterways, organics, powerlines and tree lines.

Since Ceres began offering drone application in 2023, several growers have set aside plots in hilly and waterway areas for them to test spraying in.

If these descriptions match any of your fields, drone application may be a good fit.

Field Size

The size of the field needing sprayed is a large factor as well. According to US aviation regulator, the Federal Aviation Administration (FAA), pilots can only spray what they can see; and as of now spraying expeditions beyond the pilot’s line of sight (BVLOS) are not permitted.

As a result, a very large field may require the drone pilot to stop and relocate several times in order to cover the entire field.

However, if you have a large field with topography that makes traditional spraying difficult, drone application still might make sense for you.

Most drone solutions providers typically charge by the acre but may also have a minimum charge per hour. In Coffing’s experience, using drones to spray smaller fields only totalling a few acres may not provide the return on investment that a farmer may expect.

It is therefore advisable to consider having a conversation with one of your trusted advisors to determine what the most convenient and economical option would be for the specific acres you’re considering for drone application.

Battery Life

The battery life on the drones completing the application is limited. In fact, it can be more limiting than the tank capacity on the drone.

According to Coffing, the batteries on his company’s drones may last anywhere from six to nine minutes depending on the field and how often the pilot must start and stop.

(Note: there are drones, like DJI’s Agras T series that can stay in their as long as 25 minutes on a single battery charge though. But perhaps that is only when they do not have to do several stops and starts). To help combat this limitation, the drone operator has keep a few standby batteries on hand to switch out.

Due to a drone’s limited battery life and tank capacity, traditional spraying with a plane or ground sprayer may be faster and more economical for a large number of acres.

If you have a large field but still want to give drone spraying a try, it’s worth noting that the batteries will last a bit longer in the morning when the temperature is cooler.

The Chemical Being Applied

Keep in mind that only certain chemicals can be used for drone application. In the US, the Environmental Protection Agency (EPA) allows drones to be used for spraying only if the concerned chemical is already labelled for conventional aerial application.

(Laws differ with countries; and it is advisable to find out what the regulations say for where a farmer is located).

This means if you already use a plane to spray your fields, the chemical being used will be fine to use with a drone as well. If you typically use ground spraying but are considering using a drone, double check the label on your chemical to ensure it can be used aerially.

Drone Regulations

If drone application seems like a good solution for your farm, or the next best thing for your business to offer, be sure to follow your local civil aviation authority’s guidelines for certification and approval to fly.

In addition to completing the initial pilot certification, agricultural drone operators in the US must notify the FAA before flying.

A Notice to Air Missions (NOTAM) must be filed before spraying with the drone, which typically takes 24-72 hours to receive back.

If an area within a controlled air space–such as near a local airport–needs sprayed, the pilot must file a Certificate of Approval (COA). This can take a week or more to receive back, but it lasts for a year.

Without the COA, the drone won’t turn on in the area.