No excuses for spray drift

 Crops 2014 speaker Rory Roten, of Lincoln Agritech, told Rural News “there’s plenty of technology out there, inexpensive or expensive, to prevent [drift].”

He gave two presentations at the Crops 2014 field day outlining some of those, but the most common mistake is to drive too fast, he says. “I wouldn’t go faster than 10km/h but I’m not a farmer,” he told one of his audiences, acknowledging there is a need to get sprays on in a timely manner.

When spraying, keeping going even though the wind has increased to exceed what’s acceptable is another common reason for problems, as is having the boom too high over the target.

The advent of GPS guidance on sprayers means relatively old solutions, like droplegs that put spray into the crop canopy, or hoods to keep spray off crops but on weeds growing between rows, have renewed potential, he added.

A drift study by Lincoln Agritech found various drift reduction technologies (DRTs) cut spray reaching 2-20m downwind of the target area by 34-60% compared to standard 110o, 03-sized nozzles. However, “most alarmingly”, air-assisted booms increased drift with 63-81% more spray deposited 10-40m away.

Simply changing standard nozzles for ones designed to reduce drift, such as air induction nozzles, is “one of the cheapest options,” Roten told the field day crowd.

Such nozzles substantially reduce the number of very fine, drift-prone drops a sprayer produces, he explained, and it is that more uniform droplet size distribution, rather than the claimed creation of larger drops with bubbles in them, that reduces the drift, he suggested.

Excessive pressure through any nozzle is likely to increase fine droplets, hence drift, so should be avoided, and adjuvant effects on spray quality should also be considered. “If you can cut the fines, you are automatically going to cut drift.”