Farm Progress

3 ways to minimize herbicide drift

Minimizing spray drift is always important, but especially with newer herbicide systems.

Tom J Bechman 1, Editor, Indiana Prairie Farmer

March 28, 2017

2 Min Read
GOOD DAY TO SPRAY? Is it a good day to spray, or should you leave the sprayer parked? Wind speed can be one of the determining factors. Spraying in even moderate wind risks more spray drift.

Managing spray drift and minimizing it as much as possible just became more critical. With dicamba herbicides now approved for use over dicamba-tolerant crops, minimizing spray drift is a must. But even if you’re not using one of those products, it’s still important.

Bryan Young lays out three basic rules as the cornerstones to managing and minimizing spray drift. Young is a Purdue University weed scientist.

1. Choose nozzles that produce larger droplets. The industry is helping by developing newer nozzles that develop coarser droplets and still work efficiently, Young says. If your sprayer is still equipped with conventional flat fan nozzles that were popular prior to glyphosate-resistant crops, it’s time to switch them out, he says.

There are many nozzles that can do a much better job today and that produce coarser droplets, which are less subject to drift. Any nozzle that produces medium-size droplets and fines is going to be difficult to manage when trying to limit drift.

2. Lower the boom on drift — literally. Boom height is a big deal if you’re trying to keep spray droplets at home and not lose them to air currents. The new dicamba labels list a maximum boom height above the target of 24 inches. Often you may be able to run the boom even lower than 24 inches, Young says. One limiting factor may be 120-foot booms in sloping fields. Sometimes slightly shorter booms are an advantage if you’re spraying lots of rolling fields.

One rule of thumb says boom height above the target should equal the spacing between the nozzles on the boom, Young explains. So if nozzles are spaced 20 inches apart, then try to run the boom 20 inches above the target.

3. Don’t spray if wind exceeds top speed on the product label. One way to zero in on wind speeds is to carry a device to measure wind speed in the cab, Young says. There is even technology available that will automatically record wind speed and other conditions as you spray.

“What’s good about that is that you have a record if someone later claims you sprayed when it was too windy and [product] drifted onto their garden,” he says. “What’s potentially bad about that is the same thing: You have a record if you are in a jam and spray when it’s really windier than when you should be spraying. Documenting environmental conditions while spraying cuts both ways.”

About the Author(s)

Tom J Bechman 1

Editor, Indiana Prairie Farmer

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