Calibrate Field Sprayer
Even new or nearly-new field sprayers equipped with what appears to be a good set of nozzles can produce disappointing results if just a bit of dirt, sand or some other defect in the equipment goes undetected. Taking a few minutes to properly calibrate the sprayer can provide peace of mind that crop protection products are at least being applied properly.
Here are a few simple steps to follow to properly calibrate the sprayer requiring a few basic tools: a timer (a watch or smart phone) showing seconds, a measuring tape and a jar graduated in millimetres or ounces.
- Measure distance and time
- Place two stakes 50 metres apart in the field
- Select the gear and throttle setting (r.p.m.) at which you plan to spray
- Fill the sprayer half full of water
- Drive the distance between the stakes three times, timing each pass. Each time, make sure the tractor is at the desired speed as you pass the first stake. Keep driving at this speed until you pass the second stake.
- Take the average time of the three passes
- Measure the average nozzle output
- Park the sprayer and run at the same pressure as the test run.
- Collect the output from each nozzle for the average length of time needed to travel the 50 metres in the test run.
- If any nozzle is more than five per cent above or below the average output, it should be cleaned or replaced
- Measure the nozzle spacing in metres
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Use the following formula to determine the sprayer output:
Sprayer Output (L/ha) = (Average Nozzle output (mL) / Nozzle spacing (m)) x 0.2
- Farmers who prefer to measure in litres/acre or gallons/acre, can use the following conversion guide:
- Litres per hectare x 0.4 = Litres per acre
- Litres per hectare x 0.09 = Imperial gallons per acre
- Litres per hectare x 0.11 = U.S. gallons per acre