Saving money and the environment are two objectives common to most farmers. But sprayer calibration, a practice that can do both, is not common enough.
Three out of every four farmers overspray or undersrpay more than the 5-percent cushion around the inteded rate, says Erdal Ozkan, an Ohio State University professor in agricultural engineering. The 5-percent cushion above or below the intended rate is the accuracy level recommended by the U.S. Department of Agriculture and the Environmental Protection Agency.
Most farmers are over-applying spray at an average of 23 percent, Ozkan says. Knowing this, a farmer who set aside $4,000 for pesticide purchases could save nearly $1,000 by properly calibrating his sprayers. For a farmer setting aside $10,000, about $2,300 could be saved.
“A 20-minute calibration could save a farmer thousands of dollars,” Ozkan says. “That might be the most profitable 20 minutes that one could and shold spend to help the budget in tight economic conditions.”
Farmer should calibrate sprayers several times throughout the year.
There is a direct correlation betweent he number of calibrations and the accuracy of the sprayer, Ozkan says. According to a University of Nebraska study, nearly 70 percent of farmers who calibrate more than once a year spray within the 5-percent recommendation. This is compared to 95 percent of farmers who missed the mark when only calibrating once a year or less, he says.
In particular, calibration should be more of a concern to fruit and vegetable growers who do multiple spray applications during the growing season. Insecticides and fungicides are applied more often than herbicides and in some cases are sprayed weekly on fruit and vegetable farms, Ozkan says. If the sprayer is not calibrated, the error is repeated each time.
Other farmers should calibrate sprayers when changing fields to accommodate the variance in landscape. The differences in ground conditions (soft vs. hard) and the slope of the field can cause a difference in travel speed, which affects application rate, Ozkan says.
Calibration also should be checked when the type of liquid chemical is changed.
There are several ways to calibrate a sprayer and each should take less than 30 minutes. Details on specific processes can be found in the Ohio State University Extension Fact Sheet 520 (“Boom Sprayer Calibration”), which is also available electronically by clicking here.
Small changes in calibration can be made by adjusting the pressure, Ozkan says. Larger changes can be made by adjusting travel speed or by replacing nozzles with other of the appropriate size.