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How to calibrate the Agrowdrill AD083

Correct calibration of your seed drill will improve metering and result in more cost-efficient sowing

There are four steps for calibrating your AD083 seed drill:

  1. Set the gates and restrictors
  2. Set the sowing rate
  3. Calculate the actual sowing rate
  4. Adjust the sowing rate to suit your desired output

TIP: There are a number of factors that influence sowing rates. These tables are offered as a guide; your machine may need slightly different settings.

We recommend you calibrate your machine according to the following instructions and re-check the results after a hectare to ensure consistency and accuracy. 

1. Set the gates and restrictors

  • Check the restrictor and gate settings recommended for your seed and/or fertiliser in the recommended restrictor and gate settings table.
  • Fit restrictors to your seed rollers as described in the table. 
  • Adjust the roller gates according to the recommended rate. 

The roller gate adjustment levers are located on the right-hand side of the machine. They can be adjusted by rotating the handle anticlockwise to loosen the handle, then sliding the lever to the desired setting. Once in place, rotate the handle clockwise to lock it in place. 

NOTE: The gate setting levers allow broad calibration changes, usually based on seed type and size. Do not adjust gate settings to increase the application rate. This can be adjusted using the rate adjustment levers, which allow for much more precise changes. 

The fluted seed rollers have a fine and a coarse side. This design allows both small and large seeds to be accurately metered. Apply restrictors by positioning them sideways above the seed roller and twisting them into place in the adjustable stoppers. There should be an audible click as they are positioned. 

For more information on restrictor positioning for different seed and fertilisers, see how to reposition seed roller restrictors

Recommended restrictor and gate settings


Gate setting

Restrictors fitted

Lupins 1 None
Barley 0.6 2 of 4
Oats 0.8 None
Wheat 0.6 2 of 4
Sorghum 0.6 2 of 4
Canola 0.2 3 of 4 (leave fine tooth exposed)
Sub clover 0.2 3 of 4 (leave fine tooth exposed)
Lucerne 0.2 3 of 4 (leave fine tooth exposed)
Ryegrass 0.2 2 of 4
Single super 0.8 None or 2 of 4
DAP 0.6 None or 2 of 4
Urea 0.6 2 of 4

restrictor setting

2. Set the sowing rate

  • Set the rate adjustment lever to the desired application rate (measured in Kg/Ha) as described in the calibration chart
Varibox on the AD083

The rate adjustment lever can be found on the varibox, which is located on the left-hand side of the platform. To adjust the rates, rotate the handle anticlockwise to loosen and slide the lever up and down to the desired setting. Once in place, rotate the handle clockwise to lock it in place. 

Tip: The rate adjustment lever on the varibox should be free but firm. Ensure the wing nut that secures the varibox lever is tightened securely to prevent it loosening during sowing. 

Calibration Chart

Artboard 1

NOTE: This chart is a guide only. Seed sizes can vary between varieties, from season to season, and crop to crop. Oaten and barley varieties, in particular, can also be affected by the cleanliness of the sample. Always check the application rate prior to sowing. 


3. Calculate the actual sowing rate

Once the sowing rate has been set, you need to measure the actual volume of product being passed through the seed rollers in order to adjust the sowing rate to your target output.

  • Add the seed or fertiliser being calibrated to the seed box. You need enough to completely cover the outlets being calibrated. The outlets being calibrated are the ones that feed into the calibration tray. 
  • Remove the spacer tray and replace it with the calibration tray. 
  • Prime the seed rollers by rotating the drive wheel anti-clockwise until product appears in the calibration tray. 
  • Empty the trays and replace the calibration tray under the seed rollers. 
  • Turn the drive wheel anticlockwise (in the direction of travel) the number of turns specified in the 'crank handle turns' section of the calibration table. 
  • Weigh the resulting product and calculate the application rate (in Kg/Ha) according to the following formula. Use the calibration table to find the correct calibration factor. 

Calibration Formula

Calibration weight to collect (grams) = target amount (Kg) ÷ calibration factor

Calibration Table

AD083 Model

10 rows

11 rows

17 rows

18 rows

Sowing rows 10 x 175mm 11 x 159mm 17 x 159mm 18 x 150mm
Sowing width 1.75m 1.75m 2.7m 2.7m
FarmScan pulse metres 1.270 1.439 1.439 1.524
Collect from no. of hoses 5 5 5 5
No. of drive wheel turns 63 63 41 41
Calibration factor 0.100 0.110 0.170 0.180

4. Adjust the sowing rate to suit your desired output

  • Use the rate adjustment lever on the varibox to make minor adjustments to the sowing rate. 
  • Repeat step 3 and recalculate the sowing rate until the target output is achieved. 
  • Remove the calibration tray and replace it with the spacer tray. 
  • Place a known amount of seed in the hopper and calculate the expected area to be covered with this quantity of grain. Review the application rate by sowing that area and confirming the correct amount of seed has been sown. 

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