When I’ve asked sprayer operators to define calibration during workshops, their responses cover a wide range of activities. Here are the three most common definitions:
- Sprayer inspection (e.g. is it worn out, broken or leaking?).
- Adjusting the sprayer settings to match the crop and the environmental conditions (e.g. should semi-dwarf trees in high wind be sprayed like nursery whips in high humidity?).
- Confirming sprayer output (e.g. is the rate actually sprayed per hectare what it should be?).
Convention would suggest that answer number three (confirming sprayer output) is the correct definition for sprayer calibration. However, I feel that calibration is holistic and includes elements from all three answers – it’s simply a matter of knowing when to do what and why.
Why should I calibrate?
No matter the definition, regular airblast sprayer calibration is essential because:
- Calibration confirms the sprayer is functioning correctly.
- Calibration confirms each nozzle is delivering the desired rate (e.g. L/min. or gal./min.) and spray quality.
- Calibration ensures the desired rate (e.g. L/ha or gal./ac) is applied to the crop.
- Calibration improves coverage and reduces product wastage (i.e. saves money and reduces unnecessary environmental impact).
When should I calibrate?
This depends on which of the three definitions you have in mind:
Where do I calibrate?
Again, this depends on which of the three definitions you have in mind:
The obvious question of “how do I calibrate” is a huge topic, and way too much for a single article. It is a requirement of Good Agricultural Practices (GAP) to calibrate any sprayer, but presently, GAP doesn’t specify the calibration method. Be sure to regularly perform all three varieties of calibration according to use and your sprayer manufacturer’s maintenance schedule, and keep your records up to date.