# A Step-by-Step Guide: How to Calibrate Your Sprayer

JUNE 2018

An accurate calibration is essential for any spraying function as it ensures that the chemical is applied at the rate intended on the product label. Application in excess of the recommended rate is prohibited, as it can damage plants/foliage and it is uneconomical.

But what does it actually mean to calibrate your

This is a calculation to ensure you are applying the correct amount of liquid (chemical + water) to a certain size or area. So here’s a few basic steps to help you calibrate your

## Step 1: Check the Calibration on Your Sprayer

### Check Nozzle Output

Fill the spray tank with clean water. Run the sprayer at the correct pressure with all nozzles operating.
Place a measuring jug under first nozzle for one minute. Measure how much water is in the jug.
Repeat for all nozzles. Nozzle output should not vary by more than 10%. If it does, the nozzle could be worn or damaged and should be replaced. All nozzles on the boom should have a similar output.
Add all the jug measurements to find the total sprayer output in litres per minute.

Average Output = 41.9 L/min

### Calibrate the Sprayer

Speed (km/h) = 360 divided by Time (seconds) and measure Time per 100 Metres

Example:
Speed = (360 ÷ 41.9) = 8.6 Km/h
Output = (1.40 x 600 ÷ 0.5 ÷ 8.6) = 195.35L/min

## Step 2: Get the Initial Data

This will give you the Spray Volume, Product Dose & Spray Quality

Example:
Spray Volume = 200 Litres / Hectare
Product Dosage = 50 Litres / Hectare
Spray Quality = Medium

### Measure Time

Measure time (in seconds) per 100 Metres

Example:
Time = 41.9 Seconds

### Calculate Speed

Calculate Speed – SPEED (km/h) = 360 divided by TIME (seconds)

Example:
Speed = (360 ÷ 41.9) = 8.6 km/h

### Nozzle Spacing

Measure the nozzle SPACING – Usually 0.5 metres (50cm)

Example:
Spacing = 0.5 metres

### Measure Quantity per Minute

Measure TIME per 100 Metres – OUTPUT (L/min) = VOLUME (L/hec) x SPEED (km/h) x SPACE (metres) ÷ 600

Example:
Quantity = (200 x 8.6 x 0.5 ÷ 600)  =  1.43 L/min