Great Plains 2525P Material Rate - Manual (Page 66)

118-960B 10/19/2010
Great Plains Mfg., Inc. 66
Fertilizer Density Correction
The Fertilizer Rate charts in the Seed Rate manual are
based on a StandardDensity of:
65 pounds/cu-ft or
1.04 kg/liter.
If your material is substantially different, and/or if you
don’t intend to calibrate, calculate a CorrectedRate
before consulting the rate chart.
1. Obtain your material density from the packaging. If it
is not documented, you will need to weigh a known
volume of it, and convert the results to pounds-per-
cubic-foot or kilograms-per-liter.
2. Compute the correction factor.
3. Apply the correction factor to your desired applica-
tion rate.
4. Look up the setting for the CorrectedRate in the Fer-
tilizer Rate chart.
5. The CorrectedRate is used only to obtain an initial
setup for the rate adjuster. Calibrate to your real field
rate (the ActualRate).
Fertilizer Rate Calibration
Calibration is strongly recommended. Fertilizer density
and granularity can be substantially different from the
material used to generate the chart.
Refer to sample data and formulas at right.
1.
Consult the rate chart for your material (after correct-
ing for density, if that step was completed).
2. Set rate adjuster on one of the drill boxes.
3. Record weight of an empty container large enough
to hold material metered for one acre for three rows.
4. Place several pounds of material over three fertilizer
drop tubes on an outside end of a drill box. Pull deliv-
ery tubes off of these three openers and route them
to container.
5. Raise the drill.
6. Rotate gauge wheel or calibration crank a few turns
to confirm gearbox has engaged and to confirm that
the fertilizer paths are free from foreign matter.
7. Turn gauge wheel several times to verify even flow of
material from the three fertilizer drop tubes. Place
materials collected so far back in box.
CorrectionFactor
StandardDensity
YourDensity
---------------------------------------- =
CorrectedRate ActualRate CorrectionFactor
×
=
Example Fertilizer Density Correction
Drill: 2010HDF-2410
Desired Application Rate (ActualRate): 60 lbs/ac
Fertilizer Density:
42 pounds per cubic foot.
CorrectionFactor:
65
÷ 42 = 1.55
CorrectedRate:
60 x 1.55 = 93 (pounds/acre)
The closest chart rate to 93 is 92.
Use adjuster setting: 50
For example:
Drill: 2010HDF-2410
Assuming the material density corrected earlier:
ActualRate: 60 (pounds/acre)
CorrectedRate: 93
Rate Adjuster setting from chart:
50
Assume empty ContainerWeight of:
1.1 pounds