Great Plains 800 Material Rate - Manual (Page 31)

Great Plains Manufacturing, Inc. Table of Contents Main Box Rates Small Seeds Rate 29
2011-10-25 Table of Contents Main Box Rates 175-057B
3. Disengage the lock-out hub (see Operator manual),
to permit independent rotation of the main jackshaft.
Refer to Figure 9
4.
Remove the calibration crank from its storage stob
on the left top side of the main tool bar. Store the
retaining pin on the stob.
Refer to Figure 10
5.
Place the hex socket of the crank on the left end of
the main jackshaft.
6. Pull the small seed hoses off the top of three opener
seed tubes, at the top of the openers. Place the
hoses into each sample container.
7. If not already done, set the Small Seeds Rate
Handle. If fertilizer is loaded, remove the fertilizer
drive chain (unless you are simultaneously
calibrating fertilizer rate).
8. Load seed above the rows to be sampled. Load well
more than the expected sample size.
9. Rotate the crank several turns counter-clockwise to
ensure that the drives and seed cups are engaged,
working properly, free from foreign material, and that
seed is flowing steadily from the meters. Stop.
10. Note the current reading of the acremeter, unless
you do not plan to rely on it for the calibration.
11. Empty the sample containers back into the seed box,
and place them back under the three hoses to gather
metered seed.
12. Turn crank at a steady rate until one tenth acre or
hectare is tallied on acremeter. While turning, check
that cups have ample seed coming into them.
13. Weigh metered material. Subtract initial weight of
container(s).
14. Divide the net material weight by three. Multiply by
number of openers on your drill to determine the
total of pounds per acre applied.
15. Divide the desired original field rate by the measured
rate to calculate a scale adjustment factor.
Row Spacing Rotations Per Acre (ha)
6 in. (15.2cm) 728 (1799) rotations
7
1 ⁄
2
in. (19.1cm) 728 (1799) rotations
Figure 10
Calibration Crank Engaged
28068
Example: on the 12-row 7
1 ⁄
2
inch drill, planting alfalfa at
12 pounds/ac has an initial small seeds rate handle
setting of:
60
Rotations for one tenth acre is:
72.8
Example:
the three containers weighed a total of
1.04 pounds after test: NetWeight is 0.35 lbs
0.35 1.04 0.69 – = NetWeight GrossWeight ContainerWeights – =
Example:
a 12-row (7
1 ⁄
2
in.) drill: MeasuredRate is 10.6 lbs/ac
10.6
0.35
3
----------- 12 Ч 10 Ч = MeasuredRate
NetWeight
3
--------------------------- RowCount Ч 10 Ч =
Example: the target rate was 12 lbs/ac:
the correction factor =1.2
1.13
12
10.6
-----------
˙
=
CorrectionFactor
FieldRate
MeasuredRate
-------------------------------------- =