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Drone image reveals best cutting day

Infrared aerial photo technology senses when alfalfa quality is prime

Matthew Johnson of M3 Aerial Productions with the UAVs his company uses to capture images to determine hay crop quality.

The Manitoba Forage and Grassland Association (MFGA) and M3 Aerial Productions are teaming up to investigate whether unmanned aerial vehicles (UAVs) ­— also known as drones — can be used to enhance the MFGA’s Green Gold Program, which provides producers with the best first-cut date for alfalfa crops.

The MFGA offers the Green Gold program, which originally began as a Manitoba government initiative 21 years ago. Offered at no cost to producers, the generosity of sponsors helps fund the program. Participating producers clip samples of alfalfa from their fields twice a week which are sent to Central Testing Laboratories — a core partner in the program — for evaluation. Program co-ordinator, John McGregor emails regional results to subscribers, posts them on the MFGA website and sends them to various media. More than 500 producers and industry people receive information from the program, all geared to identifying the optimum timing for first-cut alfalfa crops when the relative feed value is the highest. The first-cut date for 2016 was May 30.

Aerial vs. ground data

As part of the trial project, a handful of Manitoba producers participating in the Green Gold program this year not only took clippings, but also had aerial images of their crops taken by camera-equipped drones.

“The UAVs are fitted with sensors which pick up infrared light in four wavelengths that bounce off the plants,” says M3 Aerial Productions owner Matthew Johnson. “Our software uses an algorithm to look at the light that has come back and turn it into something that’s called NDVI (Normalized Difference Vegetation Index). It basically allows you to get a reference point so you can note the variations between healthy and unhealthy plants in the crop.”

Because red and green are opposite on the colour spectrum, they have different interactions. A green plant will absorb infrared light in a certain way — the darker green the plant, the more infrared light it absorbs. A dying or diseased plant, paler in colour, will reflect more light up to the sensors. Colour picked up by the infrared sensors can indicate when a crop is at its prime growth stage.

M3 uses two drones to gather crop data. Its five-foot wide, fixed-wing Ag Eagle RX60 UAV can fly up to 500 feet above the ground, collecting data from a half-section field in around 30 minutes. Its Quad Copter drone has the ability to hover and fly at lower levels. “A producer can cover a section of land in one flight with the Ag Eagle, get a breakdown of where the problems areas are and then use the Quad Copter to fly at about five feet above the crop to get a really close look at it,” says Johnson. “A producer may be able to identify what the issue is without having to walk out into the field.

Valuable tool

“The Green Gold program is one of our most valuable programs for producers,” says Duncan Morrison, MFGA executive director. “We’re evaluating the UAV eye-in-the-sky technology to see if we could correlate what we are seeing with the lab results. It also gives us all a broader scope as well. It definitely supports the existing program, which will continue to be of great value as we look at ways to get the best information possible out to producers, while attracting sponsors for the program.”

“Farmers around the world are being educated on the benefits that UAVs can provide to their operations,” says Johnson. “From increasing efficiency and profitability, to decreasing waste and environmental impacts, the solution is clear, and it is UAV-based technology. We are very pleased to have this opportunity to work with and help MFGA showcase their Green Gold program.”

For more information visit the M3 website.

About the author


Angela Lovell

Angela Lovell is a freelance writer based in Manitou, Manitoba. Visit her website at or follow her on Twitter @angelalovell10.



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