Smithco Turf Spraying Guide - Manual (Page 25)

7. NOTE : As a practical matter, if high application rates are desired (above 75 GPA), the measured
course length should be reduced by half (i.e. 102-ft [31 m] for 20-inch (52 cm) spaced nozzles). The
volume collected (above) is then doubled (multiplied by 2).
8. Observe individual nozzle output volumes. If an individual nozzle's is 10% above or below the
average output, check for blockages in the nozzle or in the nozzle strainer. If the nozzle is worn or
damaged, replace it.
9. Compare this actual application rate with the recommended rate. If the actual rate is more than 5%
higher or lower than the intended rate, adjustments must be made.
10. Increasing or decreasing the spraying pressure may make minor adjustments in application rate.
Lowering spraying pressure decreases application rate. Increasing spraying pressure increases
application rate. This procedure normally does not apply to spray systems controlled by an electronic
spray control system that governs flow rate.
11. Increasing or decreasing the travel speed of the sprayer if conditions permit may make adjustments in
application rate. Slower speeds increase application rate. Faster speeds decrease application rate.
12. Nozzle sizes can be changed to provide the correct application rate. Refer to the nozzle charts in this
book for the desired nozzle type.
13. Re-calibrate the sprayer (steps 2-6) after any adjustments are made.
As previously discussed, there are other acceptable methods of Turf Sprayer Calibration. Chemical suppliers,
Agricultural Extension Agents, Universities and consultants of various types offer helpful advice on this subject.
Technical catalogues are available from nozzle manufacturers.
3. TRANSFERRING THE "128" METHOD OF CALIBRATION INTO METRIC (LITERS
PER HECTARE)
The same steps are used that are used when calibrating in gallons per acre. First a relationship between a
measurable amount (milliliters) and the calibration amount (liter) is determined. That ratio is 1: 1,000.
Now an area which is 1/1,000 th of a hectare must be measured. On spray booms with 51 cm (20 inch)
spacing, mark off an area which is 20 meters (65.6 feet) long. The area formed by that length and the width of
one spray nozzle (20 meters by .5 meters) is 10 square meters which is 1/1,000 of a hectare. Therefore, the
amount of spray material applied to this small area in milliliters is equal to the amount applied to one hectare in
liters.
Then, follow the remaining steps 2-10, substituting milliliters for ounces, liters for gallons, square meters for
square feet and hectares for acres.
AVERAGE OUTPUT (MILLILITERS) = APPLICATION RATE (LITERS/HA)
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