The chance to gain a bird’s-eye view of a growing crop is one of the biggest attractions of precision agriculture, but the degree of precision depends on the tools. So far, growers and advisors have had a choice of either satellite images or those from drones or unmanned aerial vehicles (UAVs). Each has advantages and disadvantages. Satellite images are hampered by cloud cover and resolutions as low as 10 metres. UAVs or drones can provide sub-inch resolution, but are limited to several hundred acres per day. Drones are also restricted near airports.
An intermediate option is being tested in a pilot project to use aircraft to take images from higher than a drone but lower than a satellite. The project is managed by Veritas Farm Management, based in Chatham, Ont. and owned by Deveron Corp. It’s working with Ceres Imaging to provide intermediate-level imagery of 25,000 acres of subscriber fields across southern Ontario during the 2021 growing season. Flights began in late June, with subsequent flyovers of the same fields planned for late July and late August.
The project was aided by Deveron’s continuous growth in the past decade and a partnership based on Ceres Imaging’s involvement in fixed-wing imagery. The latter had been working with NDVI (normalized difference vegetation index) imagery to assess irrigation needs and nitrogen recommendations in parts of the U.S., and when Veritas manager Aaron Breimer saw what it could do, he started discussions with several ag retailers around Chatham. They decided to approach Ceres with the goal of this 25,000-acre project, though normally the company works with a minimum of 50,000 acres.
“They’ve done a lot of work on different bands of imagery and created indexes,” says Breimer. “NDVI is an index because it’s a combination of red light and near-infrared light and they used a mathematical equation to create their own algorithms. They’re able to give us an indication of what parts of the field might be suffering drought stress.”
A view from 10,000 feet
Working with fixed-wing imagery is a significant change from the high-res capabilities of drones and the lower-resolution offerings of satellites. Breimer notes the area covered is a big advantage. The pilot project targeted 5,000 acres per day, while a drone can cover only 500 acres in the same time.
“And if I’m going to do 500 acres with a drone, those fields had better be tightly knit together,” says Breimer, noting the other big challenge — restricted use around larger regional airports.
Paul Hodgins was Breimer’s choice for the project. The Hodgins family has been in the aerial application business since 1962, with Paul operating under the name General Airspray Ltd., based near Lucan, north of London. The family’s primary focus has been working with the forestry industry. They have used aerial photos to identify blocks they were treating, and conducted seeding and chemical applications.
“We’ve worked with Aaron on various spraying and seeding research projects over the years,” says Hodgins, who installed his first GPS guidance system in 2001. “He contacted us early in 2021 to see if we’d be able and interested in participating in a project of this scope. Our flight crews are used to flying precise flight lines using only lightbar guidance information.”
Hodgins echoes Breimer’s comments about how transponder codes change the potential for fixed-wing imagery. Flights are conducted at 10,000 feet above ground and are monitored and controlled by Nav Canada to avoid conflicts with other aircraft. He also shares Breimer’s cautious optimism on the adaptability of higher-res imagery.
“The adoption of this technology to many growers may be of interest only,” says Hodgins. “But if researchers don’t collect this type of data, we won’t learn to react to the changing environment in order to more effectively manage the grower’s crops.”
The technology's changing
Managing real-time data from lower-level fixed-wing flights is another challenge. The pace at which some companies are installing sensor technology and cameras continues to quicken.
“That’s evolving over time where you have sensor companies that have four or five lenses that are collecting 10 different spectrums, and they’re expensive,” says Breimer.
“But the nice thing with fixed-wing is you can have an RGB or near-infrared or it’s RGB and near-infrared that’s combined to give you NDVI. You can have that red edge, you can have thermal sensors giving you more from that one flight.”
But with such a huge volume of data to manage from one flight, how quickly can it be correlated and put into the hands of growers?
Breimer says the goal is within 24 hours, although it will depend on how quickly data can be pushed through the internet.
“Obviously, you’re talking about big data that are coming in, so we’ve made an investment to have a hub near Lucan to be able to push the data as soon as the plane lands.”
He says Ceres works with data-processing companies around the world, so as soon as the imagery starts to upload, they can start to stitch things together.
From there, ground-truthing will be required to differentiate the findings and determine precisely what specific information the imagery provides.
The future fit
As for the plans for 2022, Breimer says it will depend on the results from 2021. If there is an indicator, it’s in the acceptance of thermal imagery. Ceres has been involved in helping with assessing the need for irrigation in different parts of the U.S., and he believes the same could become the norm for Ontario agriculture. If growers find value in the level of detail from thermal imagery, things will change.
“The thermal sensor is going to give us a chance to quantify things — for instance, if there’s a value investing in overhead irrigation,” says Breimer. “With land prices in Ontario at $25,000 to $30,000 per acre, we’ll have drought stress in some locations in Ontario, meaning irrigation — large-scale — and not just on the sands of Norfolk or Elgin but on heavier clays.”
Another intriguing development from 2021 has been the use of thermal imagery combined with NDVI to identify early outbreaks of sclerotinia (white mould). The disease often starts in the highest NDVI area of a field yet those also tend to be the coolest (since healthy plants can regulate their temperatures better). If a hotspot were to show up in a high-NDVI area, it could be similar to those healthy plants having a “fever.” As Breimer says, there’s no guarantee that is what they’ll find but it’s a hypothesis they’re testing.
Breimer says growers are generally resistant to developing prescription maps or using precision ag tools to their fullest extent, often citing frustration with gathering data and looking for support from their agronomic network. The problem comes when some within that network also have product — seed, inputs or equipment — to sell. Breimer says he understands that each side is looking for balance.
“Farmers are collecting all of this data and people keep telling them their data is worth so much, and they’re saying ‘I’m not seeing it,’” says Breimer. “Farmers are saying, ‘I would really like to utilize this, but is it actually making me money?’ The potential is there, we just have to figure out whether it actually adds value, and that’s why we have to be careful and it’s why we’re walking through it as slowly as we are.”