This Alberta farmer will not go back to one flat-rate fertilizer blend

Pat Kunz estimates it takes two or three extra bushels of wheat yield or perhaps an extra bushel of $9 to $10 canola to cover the cost of using variable rate fertilizer technology (VRT) on his Bieseker, Alta., farm.

That includes soil testing, analysis of yield data, and having a professional prepare the VRT fertilizer prescription.

And while he hasn’t crunched all the numbers from the 2008 harvest yet, there is no doubt in his mind that he more than covered the VRT costs with increased yield on this 2,300 acres of cropland this year. Although, it wasn’t necessarily the primary objective, he also knows he used less fertilizer this past season, compared to other years.

Kunz says using VRT has helped him improve fertilizer efficiency — as in, producing more bushels with the same amount or less fertilizer.

“When you look at the soil analysis over our farm, some of our poorer producing sites had up to 200 pounds of residual nitrogen in the soil, while some of the better sites had zero residual nitrogen,” says Kunz, who runs a mixed farming operation along with his father Chris and brother Kevin. “That tells me that on the poorer sites we wasted fertilizer and on the better sites we weren’t applying enough. With variable rate technology you can cut back what you apply on the lower producing sites and move some of that fertilizer to those sites that have medium and high yield potential. I know we used less fertilizer this year, than we have in the past, and yet our yields were better.

“In past years we would have a single fertilizer blend for the farm and just kept getting loads from the plant as needed until we had covered the whole farm. This year we could pick up exactly what we needed for each field. It was much more measured.”

Along with using the VRT and agronomic services provided by local agri-service company DynAgra, based in Bieseker, Kunz also had to equip a seeding system to apply fertilizer at variable rates.

The drill and controller

“We needed to replace our old air seeding system anyway, and

“You need a controller than can read a prescription file. Nearly every manufacturer will to tell you their seeding system is equipped for variable rate, but a lot of the times that could just mean hitting a button and you can apply 10 per cent more or 10 per cent less fertilizer. It isn’t true variable rate.”

— Garth Donald, DynAgra

we looked at several different manufacturers before we bought the Bourgault system,” says Kunz. “We knew we wanted something that could handle variable rate technology.” Their old Concord air seeding system was set up to apply anhydrous ammonia. At one time, NH3 used to be one of the more economical forms of nitrogen fertilizer, but that price benefit has largely disappeared. As well, Kunz says due to concerns about safe storage and handling, anhydrous is getting more difficult to find that form of fertilizer.

In 2007, Kunz bought a 54-foot Bourgault 5770 air drill with a 6550 ST four-compartment tank. To accommodate variable rate fertilizer application, the one upgrade option was a Zynx X20 monitor and controller, which cost an extra $20,000.

“With newer air seeding systems the controller is really the only extra piece of equipment you need,” he says. “And depending on the system, there are different makes and models of controllers you can get. With our old Concord, we had five different monitors in the tractor cab, each showing us something different. With the Bourgault system, we have one monitor/controller that does it all.”

With the equipment ready to go, DynAgra provided Kunz with the fertilizer prescription for each field. That information was downloaded onto a memory stick, or flash memory card, which Kunz simply plugged into a USB port on the side of the Windows-based Zynx controller. The controller mounts in the tractor cab. The wiring harness from the air drill is attached to the monitor and the whole system is good to go.

The basic tools needed to make VRT possible are a global positioning system receiver and the controller, says Garth Donald, senior agronomist with DynAgra.

“You need the GPS so you can orientate the tractor and the air seeding system in the field,” says Donald. “But you also need a controller than can read a prescription file. Nearly every manufacturer will to tell you their seeding system is equipped for variable rate, but a lot of the times that could just mean hitting a button and you can apply 10 per cent more or 10 per cent less fertilizer. It isn’t true variable rate.

“What you need is a controller that can read a prescription file. Flexicoil has task controllers, Bourgault and Morris have the Zynx controllers, and other manufacturers have their own systems. As long as what you have can read a prescription file, then likely you can apply variable rate fertilizer.”

Donald says controllers capable of handling variable-rate application range from a bare bones $2,000 model to the Cadillac $25,000 systems. A $2,000 model likely doesn’t include some of the wiring and hardware needed to make the system work, may or may not include a monitor, and very likely can apply only one product at variable rates.

On the other hand the $20,000 to $25,000 controllers include a nice monitor, have on-screen mapping, perform a wide range of other functions, and can handle the variable rate application of up to seven different products.

Older seeding systems can be upgraded to accommodate variable rate technology. It is not so much the hardware or the “iron” itself, it is the computer or electronic technology that’s missing, says Donald. Upgrading an older airseeding system involves the cost of the controller and perhaps the wiring harness. “And that can be expensive,” he says. “You need to talk with your equipment dealer or a company providing VRT services to get an answer that’s specific to the equipment you have. In some situations it may be more economical to update the seeding system than to try and upgrade the old air seeder.”

Kunz’s new air drill has a mid-row banding system. Seed and starter fertilizer are applied through shanks on 9.5-inch spacing equipped with narrow 4.5-inch sweeps. Urea is applied through disk openers that run between the seed rows and is placed one to 1.5 inches below the seed.

One compartment in the tank holds straight urea (46-0-0), another compartment holds seed and a third compartment holds a starter blend of phosphate, potash and sulphur, which is also applied in the seed row.

Kunz loads the fertilizer tank with the respective products, and plugs the VRT prescription into the Zynx controller in the tractor cab. He pulls into a field with the seeding system, makes sure the GPS system and the Zynx controller are reading each other, activates the auto steer feature and begins seeding. He can watch his seeding progress over the colour-coded map of the field, which appears on the monitor of the Zynx controller. Each of the five colours on the field map represents an area of the field with different production capability, and will receive a different fertilizer rate to correspond with the yield potential.

Kunz also set up seeding rate and fertilizer trials on 200 acres this year to compare variable rate to conventional seeding. In the trials, he not only varied fertilizer rates, but also seeding rates. Data from those field scale plots has yet to be analyzed.

“There is a steep learning curve, but it is actually a very simple system once you start using it,” he says. “I have no doubt it is making more efficient use of the fertilizer. We are convinced on this and we don’t plan to go back.”

Lee Hart is field editor of Grainews, based in Calgary. Contact him at 403-592-1964 or by email at [email protected]



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