28
Figure 30. Using the seed side calibration test system
Simultaneous calibration test for fertilizer and seed.
Place the machine tubes in the calibration test position. Rotate the crank a few times in order to fill the feed
chambers. Then check that each feeding device contains seed and fertilizer. Following this, empty the
calibration test trough carefully.
Rotate the crank the number of times mentioned for the machine type in question in the sowing table. The
sowing table can be found on the inner surface of the left side of the machine. The rotation speed must
correspond approximately to the driving speed used.
Weigh the seed and fertilizer that has entered the test sowing troughs. If the calibration test was carried
out with a number of rounds equivalent to an acre (reference number is given in table), the sowing amount
per hectare can be determined by multiplying the weighing results by 100.
The obtained results may differ from the desired results because of ordinary variations in fertilizer and seed
batches:
If the results obtained differ excessively from the desired feed results, the feed amounts must be
made more accurate by rotating the hand-wheel
The feed adjustment must be increased or reduced by as many percentage points as the weighed
calibration test amount exceeded or fell below the desired level
The above can be presented as follows:
Desired feed amount
New feed adjustment value =
x (present adjustment value)
Observed feed amount
If we then insert sample figures into the formula above:
Desired fertilizer feed amount = 650 kg/ha
Feed amount based on calibration test = 600 kg/ha
Hand-wheel adjustment used in calibration test = 6.5
Corrected value according to formula = (650/600) x 6.5 = 7.0
Caution! The given calculation formula is intended to simplify the determination of
correct adjustment. The end result must however always be checked with a
calibration or field test if an accurate end-result is desired!
Caution! The calculation example given above is for reference only, and is only
intended to demonstrate the use of the calculation formula.
