Great Plains 1520P Operator Manual - Manual (Page 39)

5/6/2010 118-732M
37 Adjustments
Checking Volumetric Seeding Rate
The seed charts are based on cleaned seed
and 9.5L x 15, rib implement tires. Factors in-
cluding foreign material, seed treatment,
seed size, seed weight, field conditions and
tire pressure will affect seeding rate. Set and
check the seeding rate, then readjust the rate
as necessary.
1. Record the weight of an empty container
large enough to hold seed metered from
three meters for one acre.
2. Place several pounds of seed over three
seed meters on an outside end of the drill
box.
NOTE: If drill box is full, shut off sliding
seed tubes to all but three meters on an
outside end.
3. Raise drill off ground.
4. Turn gauge wheel a few turns to fill
meters with seed and until seed drops to
ground from all three openers.
5. Place a container under the three open-
ers 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 revolu-
tions 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
meter, then multiply by the number of drill
openers for the pounds-per-acre seeding
rate.
8. If seeding rate is different than desired:
• Double check transmission sprocket
and drive range sprocket combina-
tions.
• Check for meter malfunction.
• Check for correct seed meter wheel.
• Check that all three rows are getting
seed.
• Refer to Troubleshooting on page 47.
9. Readjust transmission and/or range
sprockets and repeat test.
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
Tire
Revolutions
per Acre for
15ft drills
7.5” 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