Simple Sprayer Calibration Worksheet-Spray Smart

  1. What is the nozzle spacing (broadcast) or spray band width?

Nozzle spacing or band width / inches
Calibration distance / ft
Time to cover distance
1st pass
2nd pass
3rd pass
Average / seconds
Tractor and sprayer ID
Gear and RPM
Number of ounces collected
in time to cover distance / ounces / = / GPA
  1. Determine the proper calibration distance from the Table

located at the bottom of the page.

  1. Stake the distance out in the field and record the number of

seconds required to travel the distance. Repeat at least 2

times or until the time required is consistent. Also Record the

sprayer or tractor used, gear, and throttle setting (RPM).

  1. With the tractor in neutral and at the above RPM, collect water

from the nozzles for the above number of seconds. Collect

from one nozzle for a broadcast application. Collect from all

of the nozzles spraying one row for a banded application.

Record the number of ounces of water collected. This equals

the number of gallons per acre on a broadcast basis.

Note: you should always calibrate on a broadcast basis because

rates on herbicide labels are presented as the amount of material

needed per acre on a broadcast basis.

  1. Check the output of all the nozzles and replace any that are

more than 10% or more from the average or a new nozzle.

  1. Recheck calibration periodically and save records to avoid

confusion.

TABLE. Distance needed to calibrate sprayers using nozzle spacing for broadcast application and band width for banded application. / Nozzle Spacing/Band Width (inches) / 12 / 16 / 18 / 20 / 24 / 32 / 36 / 48 / Note: to determine a calibration distance for a nozzle spacing or band width not provided, divide 4080 by the nozzle spacing or band width in inches.
Calibration Distance (feet) / 340 / 256 / 227 / 204 / 170 / 127 / 113 / 85


Broadcast Application Example

Aatrex and Evik are being applied broadcast at a rate of 3 qts/acre and 0.5 lb/A.

The boom you are using is 60 ft wide and has a nozzle spacing of 20 inches.

You refer to the table and find that for a 20 inch spacing the calibration distance is 204 ft.

You stake the distance out and it takes an average of 15 seconds to travel.

If you catch an average of 25 ounces of water in 15 seconds, then you are applying 25 gallons per acre.

Your spray tank holds 500 gallons, so you can spray 20 acres per tank. For a rate of Aatrex at 3 qts/acre you should add 60 qts (15 gallons) of Aatrex to 485 gallons of water.

Banded Application Example

Asulox is being applied at 4qts/acre + 0.25% v/v non-ionic surfactant in a band.

Divide the desired band width (inches) by the row spacing (inches).

This will give you the % band width.

If the band width is 36 inches and the rows spacing is 60 inches this is a 60% band.

This means that for every acre the tractor and sprayer travel over you are only treating 0.6 acres. From the table you find that for a 36 inch band the calibration distance is 113 ft.

You stake the distance out and it takes an average of 10 seconds to travel.

If you catch an average of 20 ounces of water in 10 seconds, then you are applying 20 gallons per acre.

If your spray tank holds 400 gallons, you can treat 20 acres, but the tractor and sprayer will travel over 33.3 acres. For the above rates, 80 qts of Asulox, 379 gallons of water, and 1 gallon of surfactant should be added to the spray tank. It is key to remember, that the concentration of herbicide in the spray solution is the same whether the herbicide is applied broadcast or in a band.