New spot-spray technology in Canada

Weed-it can potentially save you money

Weed-it is a modular precision-spraying system, which means the number of detection sensors required for your farm size can be fit to your sprayer. Detection sensors are spaced 40 inches apart and individually control four solenoids with a nozzle spacing of 10 inches.

Precision field-spraying technology developed in Europe and licensed to a well-established distributor in Australia is now available to farmers across Canada, with the promise to help reduce herbicide costs and perhaps equally, or more importantly, help farmers afford the fight against herbicide-resistant weeds.

Weed-it, billed as the “world’s best-selling” camera-based, precision-spraying technology, has been demonstrated a few times in Western Canada over the past couple of years. It is now available to farmers looking to fine-tune their spraying operations, says Jesper Voois, Canadian manager for Croplands Equipment. Croplands, that bought the rights to market Weed-it technology, is a subsidiary of the well-known Australian-based crop protection company Nufarm, which opened its doors in Canada about 30 years ago.

The newest Weed-it Quadro sensors, mounted on the field sprayer boom, use a blue light to scan the ground to instantly detect and measure chlorophyll level in plants, and then apply herbicide to just those plants. It is described as green-on-brown technology — it can detect weeds (any green plant with chlorophyll) and ignores the brown, whether that be mature crop, crop residue or bare soil.

It is technology that generally doesn’t have a fit applying in-crop herbicide over a whole field. A conventional field sprayer can handle in-crop treatment quite nicely.

Precision spot spraying

However, Weed-it does have a particularly effective fit in three important areas. It can be effective in applying a pre-seed burndown at the start of the growing season. It can also be used for post-harvest weed control at the end of the season, and somewhere between those two points it can be effective for spot spraying a desiccant to help even out patches of immature crops, or be used to apply a pre-harvest herbicide to control troublesome weed patches.

More than 13,000 Weed-it sensors have been sold in Australia alone. The camera- based, precision-spraying technology is now available to farmers looking to fine-tune their spraying operations. photo: Croplands Equipment

The Weed-it uses green-on-brown technology — it detects weeds (any plants with chlorophyll) and ignores anything brown, such as mature crop, bare soil or crop residue.

The key feature of the technology is it controls the field sprayer to only apply herbicide to green plant material, whether that be tiny, emerging winter annuals the size of your thumbnail, a wolfy, old dandelion in standing stubble or a nasty patch of kochia in a ripening crop. In a burndown situation, for example, depending on weed populations, Weed-it has been able to reduce herbicide use by up to 90 per cent.

“The technology allows the sensor to detect only green plant material,” says Voois. “During a pre-seeding burnoff with the field sprayer outfitted with Weed-it sensors, the sprayer is only going to apply herbicide to weeds and not the whole field.”

The same principle applies during post-harvest treatment — Weed-it will only spray any green material growing in standing stubble.

“And as a desiccant, if you have a pea crop, for example, that is mostly ripe but with some patches of immature crop or weed patches, with Weed-it, it will just spray those green patches and not the whole field,” says Voois.

Each of Weed-it Quadro sensors covers a 40-inch span on the boom and individually controls four solenoids when nozzle spacing is the standard 10 inches apart. If your field sprayer has a 100-foot boom, you’ll need 30 sensors to cover the boom width.

The sensors can be operated in three different modes. The first is the spot-spraying mode, with nozzles set at 40 degrees and each sensor scanning 10-inch spacing. The second, or dual mode, with nozzles set at 60 degrees, can be set so it detects very small, thumbnail-size weeds, and it applies about a 30 per cent rate of chemical on those small weeds. As the system detects larger weeds, it gives them an extra burst of herbicide.

“The amount of herbicide applied is adjusted depending on the size of weeds,” says Voois. And the third mode is the full coverage mode, with nozzles set at 65, 80 or 110 degrees for sufficient overlap to provide proper coverage.

“It is important farmers have proper training of the equipment and a good understanding of the weeds they are dealing with and chemicals being used,” says Voois. “You’ll likely have very effective control of those tiny weeds at a 30 per cent application rate, for example, but you need to discuss that with your Nufarm rep or other crop advisor.”

Along with the spot-spraying technology, Weed-it can also effectively work at field travel speeds up to 16 miles per hour. So, you don’t have to slow down for the equipment to work.

And aside from the different sensor modes, the sensitivity of the blue light chlorophyll detection can also be adjusted. At high sensitivity the light can detect and spray very small weeds, while at very low sensitivity the system will detect only larger green plants and consider everything else it scans as background. “For example, if you’re using it pre-harvest, it is going to detect those green patches of crop and ignore the rest, or zap those kochia patches,” says Voois.

In a retrofit situation, the Weed-it sensors can be mounted on most field sprayer systems, although attention has to be paid to how much weight the boom can carry and the job may take a week or more, he says. Another option is to buy a Weed-it-ready boom manufactured by Specialty Enterprises of Wisconsin. The company’s durable aluminum booms, with brackets for holding Weed-it sensors, can be installed on most sprayers within a couple of days.

The technology can be effective in applying a pre-seed burndown at the start of the growing season, it can be used for post-harvest weed control at the end of the season and somewhere between those two points it can be effective for spot spraying a desiccant to help even out patches of immature crops, or be used to apply a pre-harvest herbicide to control troublesome weed patches. photo: Croplands Equipment

What about the payback?

So, lots of technology and a great concept to just apply chemical to identified weeds and not the whole field — an efficient spot-spraying system. But what is the cost and what is the payback or return on investment?

Well, it’s not cheap. The Weed-it system costs about $1,500 per foot of boom, so depending on boom width, it’s in the neighbourhood of $150,000.

So, what about the payback? Tom Wolf, a well-known field sprayer expert in Western Canada and one of the principals of Agrimetrix consulting services in Saskatoon, sees several benefits of the Weed-it technology.

Wolf, who provides consulting services to both Nufarm and Weed-it, says he did a lot of “soul-searching” before he decided to endorse the product. He had a close look at the technology, reviewed any research reports and even visited Rometron, the Dutch company that developed Weed-it, before making the decision. “It is technology that works and I believe can be of value to western Canadian agriculture,” says Wolf.

Voois points out that Croplands has sold about 14,000 sensors (outfitting about 600 field sprayers) in Australia and other countries over the past six years. “They are different farming systems in Australia and Canada, but in Australia during chemfallow years producers have reduced their herbicide use by up to 90 per cent with Weed-it,” says Voois.

Using some average figures for Canada, Voois estimates herbicide savings during spring burnoff and pre-harvest treatments could be in the order of $12 per acre.

Wolf says a $150,000 Weed-it system probably won’t provide a payback if only 1,000 or 2,000 acres are being cropped and treated. And, further, if you just used generic glyphosate at about $3 per acre as the reference point, saving half or more chemical application rate wouldn’t be that spectacular, he says.

“But once you get into 7,000 or 15,000 acres, the payback becomes a different calculation,” says Wolf.

“One of the greatest challenges we are facing in Western Canada is the increasing rate of weeds developing herbicide resistance,” says Wolf. “Until there is some alternative, glyphosate is still a hugely important tool for farmers using conservation farming practices. We can’t afford to lose it.”

However, he points out farmers are already seeing glyphosate-resistant kochia and Australia is reporting glyphosate-resistant wild oats.

Wolf says the strategy to reduce the risk of glyphosate-resistant weeds is to use a combination of herbicides in a tank mix, along with glyphosate.

“We’re not just talking $3 per acre anymore,” says Wolf. “As we look at multiple herbicides in a tank mix, we’re looking at $4 becoming $10 and then perhaps $15 per acre. It gets expensive. So, if you can use technology that reduces total herbicide costs for that burndown by 50 or 70 per cent and that’s your savings over 7,000 or 15,000 acres, then that becomes a significant savings and it wouldn’t take long to recover the cost of the new technology. The technology helps farmers afford the cost of at least delaying the risk of herbicide resistance.”

Wolf also likes the fact that Weed-it sensitivity can also be adjusted to provide “spot treatments” in pre-harvest applications, whether it be desiccating the crop or tackling weed patches.

“And as with any new technology, farmers get pretty creative, too, and find different uses,” says Wolf. He described the case of a western Saskatchewan farmer who this year, for whatever reason, missed doing a pre-seed burndown ahead of seeding canola.

“He didn’t get the field sprayed before seeding,” says Wolf. “But just as the crop emerged, he went in with his sprayer equipped with the Weed-it sensors, adjusted (lowered) the sensitivity of the chlorophyll reading and applied the burndown application. The sensors ignored the canola that was probably at the one-leaf stage, but then applied a spot spray to all the larger weeds.”

Voois says applying an effective pre-seed burndown with Weed-it will not only reduce the amount of herbicide used, but can potentially reduce the weed pressure in crop, which again could result in reduced herbicide applications. He also had one Alberta customer cropping about 4,000 acres who reduced the number of trips to refill the sprayer by 30 trips. “If each trip took 20 or 30 minutes, he saved himself 10 to 15 hours he could spend doing something else,” says Voois.

For more information on the Weed-it system visit, contact Jesper Voois in Calgary at 403-831-3913, or email [email protected].

About the author

Field Editor

Lee Hart

Lee Hart is editor of Cattleman’s Corner based in Calgary.



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