Great Plains 1520P Operator Manual - Manual (Page 127)

5/6/2010 118-732M
125 Seed Rate Charts
Small Seeds Attachment
To set and calibrate the seeding rate on the op-
tional small seeds attachment, follow these
steps.
Set the seed-rate handle on the small seeds at-
tachment as indicated by the Small Seeds Rate
Chart, this page.
Checking Volumetric Seeding Rate
The seed charts are based on cleaned seed and
11L x 15, rib implement tires. Factors including
foreign material, seed treatment, seed size,
seed weight, field conditions and tire pressure
will affect seeding rate. Set and check the seed-
ing rate, then readjust the rate as necessary.
1. Record the weight of an empty container
large enough to hold seed metered from
three cups for one acre.
2. Place several pounds of seed over three
seed cups on an outside end of the small
seeds box.Raise drill off ground.
3. Remove hose ends from the openers of the
three seed cups being measured.
4. Turn gauge wheel a few turns to fill cups with
seed and until seed drops to ground from all
three hoses.
5. Place a container under the three hoses to
gather seed as it is metered.
6. Using the chart on the right, select your row
spacing and determine the correct number
of revolutions per acre. Turn drive gauge
wheel the selected revolutions for your row
spacing. Check in box to make sure seed
tubes have plenty of seed covering them.
7. Weigh measured seed. Subtract initial
weight of empty container. Divide by three
for the amount metered by each cup, then
multiply by the number of drill openers for
the pounds-per-acre seeding rate.
8. If seeding rate is different than desired:
• Check to be sure all three seed cups are
covered with seed.
• Adjust seed-rate handle accordingly.
9. When finished reconnect seed hoses to op-
ners.
Equations for calibrating volumetric seeding rate:
measured seed empty container –
3 (number of meters measured)
----------------------------------------------------------------------------------------- pounds per meter =
pounds per meter number of openers × pounds per acre =
Planted Row
Spacing (Inches)
Number of
Rows for 15ft
drills
Tire
Revolutions per
Acre for 15ft
Drills
7 1/2” 24 365
10” 18 365
10” 19 346
15” 12 365
15” 13 337
20” 9 365
20” 10 329
30” 6 365
Twin Row 30” 12 365
Twin Row 30” W/S 19 346