Sprayer technology tested under on-farm conditions

Research results include the effect of wind turbulence and boom vibration.

Posted: July 26, 2005

Using field-scale equipment to evaluate sprayer application technology and herbicide efficacy gives Alberta's AgTech Centre investigators a better handle on how nozzles and chemicals work under real conditions.

AgTech Centre's custom-built field-scale sprayer

Valuable information can be learned from the conventional hand-operated research-scale sprayers, often referred to as bicycle sprayers. These units, mounted on bicycle wheels and pushed by hand, are used to apply pesticides over relatively small research plots.

Brian Storozynsky, AgTech's sprayer technology specialist, says the Lethbridge-based AgTech Centre was fortunate to have the resources as well as the available land base to conduct trials on a larger scale. Most field plots for sprayer evaluation are 24 by 82 feet (7 x 25 metres).

"Our goal was to simulate how high clearance and hybrid sprayers and the application technology performs under field conditions," says Storozynsky. "These units operate booms at various heights, travel faster, and kick up dust, so we felt we should be testing under similar conditions." The AgTech research sprayer can be operated effectively at speeds up 13 miles per hour.

The 20-foot-wide, three-point hitch mounted AgTech sprayer operates like a typical high clearance field sprayer, but you won't find anything like it commercially available, says Storozynsky.

You have to know what you're doing

Although AgTech Centre engineers and technologists built the sprayer from standard components, the boom is equipped with a five-nozzle turret to accommodate a range of nozzle types and sizes being evaluated. The custom designed console and switches are built around a Raven auto controller system.

The sprayer, which has a boom height ranging up to 46 inches above crop canopy, is mounted on a New Holland Model TV140 bi-directional tractor. The tractor carries five tanks to hold various pesticides and mixes. The system is designed, however, with no bypass lines, no agitator lines and in-line valves to avoid accidental cross contamination between tanks and lines.

"The system is built so we can change nozzles and rates quickly, adjust speed quickly, change chemical mixtures quickly, and change water rates quickly," says Storozynsky.

Original plans were to have the high clearance sprayer mounted on the rear of the bi-directional tractor and a standard sprayer mounted on the front, so an operator could perform different treatments with one unit.

But in trying to treat as many as 224 field-scale plots in a day, the centre found it was too much for one machine, so a second tractor is now used to carry the conventional spray boom and nozzles.