Basic Calibration Procedure (Continued)
Seed Calibration Procedures (Continued)
8Turn the crank handle clockwise the required number of revolutions as detailed in Table 3.
Note The Calibration is usually done for 1/80th hectare. For very small seed rates or when using inaccurate scales (i.e. unable to measure to the nearest gram) the calculation based on 1/20th hectare should be used.
Hand Crank Turns for Seed Rate Calibration
The tables represented below are for arable conditions (worked ground) and are calculated to indicate an average situation. If there is any doubt as to the accuracy of these figures for the conditions, it is advisable to run at least 1 of the 2 checks on the calibration figures listed. Refer Page 18 (Recalculating the Constant) and/or Page 19, (Wheel Slip Deviations). Check and record which tyres are fitted to your drill, to ensure use of the correct Hand Crank Turn and Constant figures.
Sowing Width | Turns for | Turns for |
(m) | 1/80 Hectare | 1/20 Hectare |
|
|
|
1.8 | 31 | 125 |
|
|
|
Table 3 |
|
|
9Weigh the seed collected during the test in kilograms.
Scales must be accurate to 2 grams, as any error will be multiplied by either 20 or 80, giving inaccurate calibration results.
10Calculate the seed rate by multiplying the kgs previously collected x 80 (1/80th ha method, refer Table 4) or x 20 (1/20th ha method, refer Table 5) depending on the requirement. If the resultant calculation does not produce the desired seed rate use the enclosed seed rate calculator disc to determine the correct gearbox setting.
Refer Use of Seed Rate Calculator Page 18
Suggestion: To be on the safe side and until confidence has been gained with the method of calibration it is advisable to conduct a second test at the newly determined gearbox setting.
For 1/80 Hectare (125m2) Calibration
Seed Rate = Actual Seed Collected (kg) x 80
Table 4
For 1/20 Hectare (500m2) Calibration
Seed Rate = Actual Seed Collected (kg) x 20
Table 5
11Where a coated seed is used it is advisable to check the calibration after 1 hectare as dressings can tend to create a coating on the seed metering wheels thus changing the the flowing properties of the seed which in turn alters the seed rate.
Pt. No. 67372
Issue 0806
17