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The keys to calibration

Graybeards who operate today's high-tech sprayers must marvel at the advances in sprayers that have been made during their farming careers.

Ninety-foot booms. Rate controllers. Space-age suspension. These advances were just a gleam in the eyes of agricultural engineers and farmers in 1980, when Successful Farming magazine partially funded an application study conducted by the University of Nebraska (U of N).

Back then, U of N agricultural engineers found inaccurate application cost farmers between $2 and $12 per acre in added chemical expense, potential crop damage, and more weeds. This information was detailed in a landmark story, "Billion dollar blunder" (April 1980).

Today's technology enables applicators to spray more accurately than back then. It's important to remember, though, that even the lowliest glitch can foul the most fancy-pants technology. Remember how a faulty O-ring brought down the space shuttle Challenger in 1986?

Well, something as simple as a plugged nozzle can ax sprayer application accuracy. Ditto for an aged speed sensor with an adhesive magnet that falls off or a mud-caked magnet. These can prompt speed sensors on spray monitors to give faulty readings.

"The monitor might be the best in the market, but if the travel speed is off, all calculations are off," says Erdal Ozkan, Ohio State University Extension agricultural engineer.

That's why calibrating your sprayer still makes sense. Sure, it takes precious time out of the busy growing season. Still, take a moment to digest these two nuggets:

  1. Sprayer calibration often takes no more than 20 to 30 minutes.
  2. It's an easy way to make $1,875 per hour.

Yes, that's right! Here's why.

It's estimated as few as 5% of chemical applications are within the 5% of desired target rates, says Bill Casady, University of Missouri Extension agricultural engineer.

Research also shows overlaps and poorly calibrated sprayers often result in overapplications of more than 20%.

"If that single recalibration saves 5% on 500 acres in an application sprayed at $25 per acre, then that 20 minutes worth of work would come in at about $1, 875 per hour," points out Casady.

That's why Successful Farming magazine worked with several Extension agricultural engineers this past year in a "Billion dollar blunder" update. This issue's story revolves around calibration readings Ozkan took on three farmer-owned sprayers against travel speeds and application rates that the farmers input into their rate controllers.

Graybeards who operate today's high-tech sprayers must marvel at the advances in sprayers that have been made during their farming careers.

David Wiley, Richwood, Ohio, and his son-in-law, Russel Fout, were the first farmers visited. The duo apply herbicides, fungicides, and foliar liquid nitrogen with a Case IH SPX 3200 sprayer.

Meeting the maximum 5% application error margin also hinges upon optimum nozzle output. Ozkan, Wiley, and Fout used a Quick Check Calibration Calculator from Greenleaf Technologies to determine the gallons per acre (gpa) that each nozzle applied.

Inspecting nozzle pressure is the last calibration step. "You have to have uniform pressure for proper flow rate to occur," explains Ozkan.

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