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In-Season Field Imaging Too Late For N Applications

Canada’s opportunity going forward is to be on the Cadillac side; that’s how

we could separate ourselves

There are several reasons to monitor a crop’s progress throughout the year. Using images from aircraft or satellites are two options. While in-season imagery may work well for some purposes, it may not always provide timely nutrient information — at least for prairie crops.

When speaking at a recent seminar, Dr. Peter Scharf, a professor at the University of Missouri’s division of plant sciences, discussed the value of aerial imaging to identify patches of nitrogen (N) stress in corn crops, which can seriously hamstring growth. He says using aircraft photos as a template for spot applying N to restore levels in problem areas has proven to be very profitable in the U. S. corn belt.

“We’re not profitable using aerial imaging to spot and correct N deficiency just any old time,” explains Scharf. “It’s when we’ve had excessive rainfall between N application and N uptake.” That can cause spring-applied N to leach out of some soils, leaving levels too low for maximum crop yields. However, he cautions growers may not see the same payback in other crops or under prairie growing conditions.

Chris Holzapfel, research manager at the Indian Head Agricultural Research Foundation, says trials conducted with top dressing N on cereal and oilseed fields at that location have shown only small economic returns. “The monetary gains are fairly modest,” he says. “But we were factoring in the cost of applying it.”

Those trials used Trimble’s new GreenSeeker technology, which allows producers to address a crop’s N needs through real-time optical imaging. N was applied before low levels became a problem for young plants.

Wade Barnes, president of Farmers Edge, an agricultural consulting firm, agrees trying to correct N deficiency by looking at aerial images isn’t as effective in cereal and oilseed crops as it is in corn. “If you do this (rely on aircraft photos) in cereal crops, by the time you realize the crop is lacking in nitrogen the damage has already been done, because yield is determined at such an early stage. It has a bit of merit with canola, but the (application) window is pretty tight.”

That lack of time to measure N deficiency through aerial imaging means it isn’t a great fit for cereals and oilseeds. “It’s hard to make those bad areas good again when you’re growing short-season crops,” adds John Heard, a soil and fertility specialist with Manitoba Agriculture, Food and Rural Initiatives. “There’s less time to intervene.”


Further aggravating the problem when using aerial imaging is it almost always involves a delay. The lag occurs between the time an aircraft flies over crops and the data is analyzed, to when a farmer finally gets equipment into the field. “Six or seven years ago we thought this was the way to go, but we quickly realized timing was everything,” says Barnes. “It’s not a quick enough process; that is why we focused on satellite imagery.”

But the overhead imaging idea may still be useful, here. “I think it has huge merit on a fungicide application,” says Barnes. “With airplane or satellite imagery you can identify those (problem) areas and place fungicides in some spots and not in others.”

Barnes also points to the value of overhead images in monitoring a crop’s overall development, allowing producers to see any trouble spots as they develop. The information could point to a variety of problems such as insects, disease or even seeding errors. “I think there is merit in following the development of the crop to see what’s going on.”


And there may be yet another way to add value by using satellite imagery. It could be used as a quality assurance tool for crops contracted to foreign buyers, particularly when sold into markets like Europe where consumers are notoriously conscious of food production standards.

Making images and input data available to buyers would allow them to monitor crops from seeding to harvest. “They can follow

the development of a crop all the way through the season,” says Barnes. “As the farmer makes an application, he can upload that information and the buyer can go in and look at any field they want. It gives them the security of knowing what’s happening.”

Barnes believes using that technique to go upmarket could be the key to maintaining grain values in the future. Problems like the discovery of GM contamination in flax exports are an example of the increasing scrutiny exports are subjected to. It’s all part of a growing demand from foreign customers for quality assurance. “I think things are going to get much more sensitive,” he says.

“As agriculture progresses, a lot of cheap grain (from a variety of developing countries) is going to come onto the market, and Canada isn’t going to be able to compete against that,” he says. “How we will be able to compete is by providing a higher value.”


“I don’t see over the next five or ten years that we want to be a (bulk) commodity producer,” comments Barnes. “They (developing countries) will end up being the lowest-cost producers, and I think buyers will separate themselves. Some will want to buy quality products and others will want really cheap [grain].”

“Canada’s opportunity going forward is to be on the Cadillac side; that’s how we could separate ourselves,” Barnes says. “Other than Australia, I don’t think anybody else can do that. That’s our sweet spot.”

Scott Garvey is machinery editor for Grainews.

Contact him at [email protected]

About the author


Scott Garvey

Scott Garvey is a freelance writer and video producer. He is also the former machinery editor at Grainews.



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