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17
Basic Calibration Procedure (Continued)
Seed Calibration Procedures (Continued)
8 Turn 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.
9 Weigh 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.
10 Calculate 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.
11 Where 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.
Table 3
For
1
/
80
Hectare (125m
2
) Calibration
Seed Rate = Actual Seed Collected (kg) x 80
For
1
/
20
Hectare (500m
2
) Calibration
Seed Rate = Actual Seed Collected (kg) x 20
Table 4
Table 5
Sowing Width Turns for Turns for
(m) 1/80 Hectare 1/20 Hectare
1.8 31 125
Pt. No. 67372
Issue 0806