Page 9
Calibrang the Sprayer
2. Determine the nozzle size and use the calibraon chart
Always follow the chemical manufacturers label recommendaons for applicaon rate (GPA). There are ve things you will need to
know to be able to gure your nozzle size and pressure seng. They are:
1. Applicaon rate — GPA or GAL/1000 Sq. Ft.
2. Speed — MPH
3. Width — Nozzle Spacing (in inches) for broadcast boom spraying
— Spray width (in inches) for boomless nozzles
4. Spraying Pressure — Follow chemical label recommendaons for pressure/droplet size requirements
5. Soluon weight and conversion factor (CF)
Spraying Soluons Other than Water
Since all the tabulaons are based on spraying water, which weighs 8.34 lbs. per USA gallon, conversion factors must be used when
spraying soluons which are heavier or lighter than water. To determine the proper size nozzle for the soluon to be sprayed, rst
mulply the desired GPM or GPA of soluon by the rate conversion factor. Then use the new converted GPM or GPA rate to select
the proper size nozzle and pressure.
Example: Desired applicaon rate is 20 GPA of 28% Nitrogen. Determine the
correct nozzle size as follows:
GPA (Soluon) x Conversion Factor = Converted GPA
20 GPA (28% x 1.13 = 22.6 GPA (Water), the applicator should choose a
nozzle size that will supply 22.6 GPA of water at the desired pressure.
See the appropriate Applicaon Chart for your boom spraying nozzle or
boomless nozzle. Using the tractor speed, nozzle width or spray width,
nozzle size being used and desired gallons per acre (GPA), nd the
pressure (psi) necessary to achieve the desired GPA.
Example for tradional boom sprayer: Assume you have found your tractor speed to be 6 MPH, your nozzle spacing is 20”, and
you want to spray 15 GPA and your sprayer has blue AIXR11003VP nozzles. Upon looking at the applicaon chart, you will nd that
you should set the sprayer’s pressure at about 40 psi in order to apply about 15 GPA.
Example for boomless sprayer: Assume you have found your tractor speed to be 5 MPH, your nozzle will cover 216 inches (18 Ft)
mounted 48” height above the target spray zone, and you will want to spray 15 GPA and your sprayer has yellow XT024 nozzles.
Upon looking at the applicaon chart, you will nd that you should set the sprayer’s pressure at about 50 psi in order to apply
about 15 GPA.
Useful Formulas
GPM =GPA x MPH x W GPM —Gallons Per Minute
(Per Nozzle) 5,940 GPA —Gallons Per Acre
GAL/1000 Sq. Ft. —Gallons Per 1000 Square Feet
GPM =GAL/1000 Sq. Ft. x MPH x W MPH —Miles Per Hour
(Per Nozzle) 136 W—Nozzle Spacing (in inches) for broadcast spraying
—Spray width (in inches) for single nozzle,
Band spraying or Boomless spraying
