OMAFRA Sprayer Calibration Calculator

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OMAFRA Sprayer Calibration Calculator

Author:	Helmut Spieser - Application Technology Specialist, Agricultural Engineer/OMAFRA
Creation Date:	01 June 1997
Last Reviewed:	09 February 2006

Field Sprayer Calibration
Hand/Backpack Sprayer Calibration
Sprayer Calibration Video
Related Links

Field Sprayer Calibration
(Determining application rates in litres per hectare)

There are many ways of determining the number of litres of spray material that are being applied to one
hectare of land - or calibrating a sprayer.

Instructions

1. Measure the time

Place 2 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

2. Measure the average nozzle output

Park the sprayer with the PTO engaged and the throttle adjusted to reach the PTO speed set in
the test run
Adjust the pressure regulator to the desired working pressure with full flow to the boom
Collect the output from each nozzle for the average length of time needed to travel the 50 metres
in the test run.
Enter the nozzle outputs into the chart below
If any nozzle is more than 5 % above or below the average output, it should be cleaned or
replaced

3. Measure the nozzle spacing in metres

4. Use the following formula to determine the sprayer output:

Sprayer Output (L/ha) = (Average Nozzle output (mL) ÷ Nozzle spacing (m)) x 0.2

5. Calculate the actual area sprayed after each tank of spray solution is applied.

Re-check the actual sprayer calibration after each tank of spray is applied by dividing the volume sprayed by the actual area sprayed. The nature of some products may slightly alter the calibration from that of clean water.

6. Growers 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

Try it!

To determine the application rates for your situation, please provide the following information.
To get this information, please follow the steps listed in steps 1 through 4, above.

Average time to travel 50 metres (164 ft):

seconds (s)

Nozzle spacing on the boom:

metres inches

Average amount of liquid collected per nozzle: (in the time entered above)

millilitres (mL)

Enter in the amounts of liquid collected per individual nozzle below (in millilitres - mL).

This will calculate the average amount of liquid collected, and will see if any individual nozzles are spraying abnormal amounts of liquid. The average will be calculated on those entered (not all fields have to be filled in). If values are entered below, they will be used (as opposed to the single average which can be entered above).

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Notes:

Sprayer calibration bottles or kits are available from a number of suppliers. For further information contact the OMAFRA Agricultural Information Contact Centre at 1-877-424-1300, or manufacturers of sprayers, sprayer parts, or herbicides.
For banded spray applications, measure the width of the of the spray band (at the soil surface or surface of the crop canopy) and enter this value into the formula instead of the "nozzle spacing." Where band spraying the acreage sprayed is NOT the same as the crop acreage. The herbicide rates referred to in most herbicide publications and labels refers to the actual area sprayed unless otherwise stated.

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Hand/Backpack Sprayer Calibration

Many people use small hand-held or back pack sprayers for treating problem areas or spraying areas that were missed. Calibration of the sprayers is as important as calibrating your field sprayer.

Instructions For Calibrating The Hand Sprayer

Method 1: Hand Sprayer

Measure out an area that is 100m².
Fill the spray tank with water.
Mark the level on a measuring stick. Pump to the pressure that will be used during the pesticide application.
Spray the water over the 100m² area.
Walk at a steady pace, taking care to apply it as evenly as possible, just as you would when
applying pesticide.
Measure the amount of water needed to fill the spray tank to the mark on the measuring stick.
This amount will be the sprayer output per 100m²

Method 2: Hand Sprayer

If the spray tank is not large enough to cover an area 100 m², use the following calibration
procedure:

Measure the amount of water needed to fill the sprayer.
Pump to the pressure you will use during the pesticide application.
Spray an area as evenly as possible, walking at a steady pace.
Spray until the tank is empty.
Measure the number of square metres covered
For example: 6m x 10m = 60 m² or 8m x 3m = 24m²
Use the recommended amount of pesticide for this number of square
metres each time you fill the tank.

Try It!

Amount of Water Required to Fill Sprayer	Litres Gallons
Length and Width of Area to be Sprayed	x Metres Feet (Length x Width)

Notes:

To convert the application rate of any pesticide to the amount required for a small area, follow this guide:
- 1 kg per hectare is equal to 10 grams per 100 square metres
- For liquid measure, 100 litres per hectare is equal to 1 litre per 100 square metres.
- One level tablespoon equal 15 mL.

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