Great Plains 800 Material Rate User Manual
Page 8
6
800
Great Plains Manufacturing, Inc.
175-057B
2011-10-25
7.
If not already done, set the Drive Type, Seed Rate
Handle and Seed Cup Doors across the drill. 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 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 seed. Subtract initial weight of
container(s).
14. Divide the net seed weight by three. Multiply by
number of openers on your drill to determine the
total of pounds per acre seeded.
15. The Seed Rate Handle scale is a percentage of
meter opening, and its effect is linear near scale
center. Calculate a new scale setting based on the
test.
Set the Seed Rate Handle to the new scale setting.
16. You may want to repeat calibration procedure at the
new setting if your results varied greatly from the
Seed Rate Chart, or if you must operate near the
ends of the Seed Rate handle scale (0-20 or
90-100).
Row Spacing
Rotations Per Acre (ha)
6 in. (15.2cm)
728 (1799) rotations
7
1
⁄
2
in. (19.1cm)
728 (1799) rotations
Example: the drill has a row spacing of:
7
1
⁄
2
in.
you desire to plant barley at:
64 pounds per acre
which, from the chart, is an initial Seed Rate Handle
scale setting of:
50 on the Drive Type 2 chart
Crank rotations for one tenth acre:
72.8.
Example: the containers weighed a total of 3.25
pounds after test. NetWeight is:
1.75 lbs net
1.75
3.25
1.5
–
=
NetWeight
GrossWeight
ContainerWeights
–
=
Example:
on the 12-row 7
1
⁄
2
in. drill, MeasuredRate is:
70 lbs/ac
70
1.75
3
----------- 12
Ч
10
Ч
=
MeasuredRate
NetWeight
3
--------------------------- OpenerCount
Ч
10
Ч
=
Example:
the target rate was 64 lbs/ac, and the initial scale 50:
the NewScale setting is:
46
46
64
70
------ 50
×
=
NewScale
TargetRate
MeasuredRate
--------------------------------------- PreviousScale
Ч
=