Spray system reduces drift

Kim Blagborne said the right particle size can not only reduce drift but ensure better spray coverage.

With growers facing increasing scrutiny from neighbors and tighter ­environmental protocols, keeping a low profile may seem like a good idea. The good news is, that’s exactly what a cross-border collaboration between Vine Tech Equipment LLC of Prosser, Washington, and Slimline Manufacturing Ltd., of Penticton, British Columbia, Canada, makes possible.

In 2000, Vine Tech introduced a line of airblast spraying equipment to North America that had originally been developed by Croplands in Australia. Vine Tech principal Jack Maljaars said the company was looking for something that could do a better job than the spray systems then available to growers. One of the advantages of the Croplands system was that it helped control drift, and allowed better targeting of sprays.

"I wouldn’t say it eliminates drift, but it controls drift much superior than a standard air blaster or any conventional sprayer," ­Maljaars said.

Vine Tech originally brought in components of the Croplands sprayers and retrofitted existing equipment, then began importing complete sprayers from Australia. The strengthening of Australia’s dollar made Vine Tech rethink the practice, however, and it began partnering with other manufacturers who could incorporate Croplands components with their own systems.

A long-standing familiarity with Slimline made the Penticton company an obvious choice.

Lightweight

Slimline General Manager Kim ­Blagborne began working with Croplands components three years ago, marrying them with his own lightweight tanks to produce systems suitable for use in a ­variety of structured crop environments.

Adjustable nozzles help reduce water requirements, making for a smaller sprayer unit, while high-powered directional fans limit spray drift and potential environmental impacts.

While a traditional sprayer might require 100 gallons or more an acre, the system Slimline offers can do the job with just 25 gallons an acre.

"Water is a precious item, so this technology allows you to use less water and do the same quality of job," Blagborne said.

"Next issue is drift; because the spray applicators are so close to the bush, there’s less potential for drift compared to some of the other systems."

Speaking to growers at the Pacific Agriculture Show in Abbotsford, British Columbia, this past February, Blagborne explained that the right particle size can not only reduce drift but ensure better coverage of a crop.

Research has shown that a 15-micron water particle (a micron is 1/25,000 of an inch) will take about two minutes to hit the ground when released from a height of ten feet, Blagborne said. Put that in a field setting, and those particles would be volatile, hanging in the air or contributing to drift. Indeed, Blagborne said any ­particles smaller than 50 microns are undesirable.

That makes the ability to adjust particle size key to the better management of spray drift.

"The whole secret is picking a size that doesn’t float," Blagborne told growers.

The ideal particle size that will help reduce the chance of sprays drifting is about 150 microns to 200 microns, at least when wind conditions are no more than nine miles an hour. Research at Ohio State University suggests that a light breeze of about three miles an hour will cause a 150 microns particle to drift up to 22 feet when released from a height of ten feet. A particle that’s just 50 microns stands to drift 178 feet under the same conditions; smaller particles travel even further.

The pressure driving a spray is also important.

Spray applicators need the ability to tinker with water pressure, the direction of the spray, and the speed of the power take-off (PTO) shaft that governs the flow of water through the system, to ensure that sprays are landing where they’re needed.

"You’re looking for products that give you flexibility," Blagborne said, noting that greater output, and greater power doesn’t necessarily mean better coverage.

The blowers should direct air to ensure sprays are directed to the appropriate areas rather than the air or ground.

"Take the time and learn calibration," Blagborne said.

An alternative to conventional boom-and-tower sprayers, a basic two-row unit from Slimline sells for $40,000, compared to a traditional single-row applicator that costs between $10,000 and $15,000. Since it does double the work for a single
cost, and reduces input requirements, ­Blagborne feels the system is worthwhile.

But it’s not for everyone, he added.

A grower with a 100-acre block would likely find it pays for itself in a year, but an orchard with a structure unsuited to over-row sprayers might not find it’s worth the investment. While different configurations are possible for different orchards, a single-row system ­may not make sense.

"If you make a single-row machine, then the uniformity of the crop is not as necessary, but then you’re basically ­getting very close to the old traditional systems—which really doesn’t warrant the capital investment that’s required," Blagborne said. 

(Prices are in Canadian dollars. The Canadian dollar is about on a par with the U.S. dollar.)