Metric native grass rates – Great Plains 3P1006NT Material Rate User Manual
Page 48
46
3P1006NT
Great Plains Manufacturing, Inc.
151-144B
2011-10-21
Metric Native Grass Rates
For U.S. customary units, see page 22.
Formulas
Metric Example
Know your Desired seed rate in pounds per acre:
TargetRate
Example target seed rate:
40 kg per hectare
Choose the number of rows to sample.
Example:
3
Weigh the empty sample container(s):
ContainerWeight
Example container are three 680 gram buckets:
2.04 kg
For a larger sample, we set the Drive Type high.
Suggested calibration Drive Type:
2
As there is only minor benefit in changing the final drive
sprocket for calibration, we leave it as is.
Example final drive sprocket:
20T
Examine the transmission for Standard vs. Seed Rate
Reduction/
Example transmission: Rate Reduction not installed:
Standard
Operate crank/gauge wheel for one tenth hectare:
CalibrationRevs
Example (s/n A1067W+):
34.6 revolutions (
1
⁄
10
th
of 346)
Weigh the collected seed plus container(s):
GrossWeight
Example:
GrossWeight = 2.96 kg
Obtain the net sample weight:
Example:
0.92 = 2.96 - 2.04, or:
NetSample = 0.92
Determine the net sample weight per cup:
Example:
0.92
÷ 3, or:
NetPerCup = 0.31
Scale the sample to drill-wide:
Example:
4.6 = 0.31x 15, or:
NetFullWidth = 4.6 kg
Scale the sample to a full hectare:
Example:
46.0 = 4.60 x 10, or:
NetPerHa = 46.0 kg/ha
Look up the number of meter shaft revolutions per ha:
CalCharRevs
for the current Drive Type, final sprocket and
transmission configuration.
Example:
Drive Type 2, 20T and Standard is:
297 cup revolutions per ha.
CalChartRevs = 297
Detemine the cup rate for this seed mix:
Example:
0.155 = 46
÷ 297, or:
WeightPerRev = 0.155 kg
Determine the number of revolutions required for the
target field rate weight metered per shaft revolution:
Example:
258.1 = 40
÷ 0.155, or:
TargetRevs = 258
Look up the Drive Type and final sprocket for
TargetRevs
Example:
Drive Type: 2
Final Sprocket: 23 T
NetSample
GrossWeight
ContainerWeight
–
=
NetPerCup
NetSample
SampledRows
---------------------------------------
=
NetFullWidth
NetPerCup
15
×
=
NetPerHa
NetFullWidth
10
×
=
WeightPerRev
NetPerHa
CalChartRevs
--------------------------------------
=
T
etRevs
arg
T
etRate
arg
WeightPerRev
------------------------------------------
=