NP2540
Fertilizer Rates
97
2019-04-12
417-459M
Select and Install Orifice Plates
If using VeriFlow nozzles, orifice plate instructions do not
apply. However, the topic “
” on page 98 applies to all types of nozzles.
Agricultural Chemical Hazard:
Wear protective gloves when changing orifice plates. Consult
material manufacturer or supplier documents for proper
handling and steps to take if skin contact occurs.
Orifice plates
at each drop line nozzle provide
back-pressure that balances flow in the manifolds,
assuring that each row obtains the same flow rate. For a
given rate, there may be more than one orifice size that
provides the recommended back-pressure.
Plates are provided with the system in three sizes.
Additional sizes are available. In general, the orifice
needs to be small enough to create a minimum pressure
in the manifold but large enough to prevent the manifold
pressure from exceeding the maximum:
15 psi min., 15-40 optimal, 65 psi max.
Using an orifice size too large can result in unequal flow
at rows. Using a size too small can cause excess
back-pressure resulting in material dumping at the relief
valve.
Determine Orifice Size
The chart below shows rate ranges for each Great Plains
orifice size and row spacing. You may need to change to
the next higher or lower orifice for a different fertilizer
solution density and/or a different ground speed.
To reduce orifice plugging and pump wear, use the
largest orifice practical for your fertilizer application rate.
For rate ranges in liters per hectare, see page 172.
Material Loss or Misapplication Risks:
Orifice size must be appropriate for rate selected. Drop line
orifice plates
do not affect rate
on ground drive pumps, and
are not used to control rate on hydraulic drive pumps. If the
orifice size is too small, over-pressure in system may result in
material loss at the ground drive relief valve. A size too small
for a hydraulic drive system may require excess pressure to
achieve the target rate. An orifice size too large may result in
uneven application across all rows.
If changing rate, changing material, changing field speed or
shutting off rows, review orifice sizing.
Figure 67
Fertilizer Drop Line Nozzle
36715
L38
L38
Orifice Plate Size
20
28
34
48
59
80
98
Recommended Rate Range in Gallons per Acre. Range is 0 - PSI
Nozzle Spacing
(Values based on: 5.0 mph, 10.7 lbs/gallon Fertilizer solution density)
30 in. Triple Coulter
3.4 - 5.5
6.3 - 10
9.5 - 15
18 - 30
28 - 46
51 - 83
80 - 131
38 in. Triple Coulter
2.6 - 4.3
5.0 - 8.1
7.5 - 12
15 - 24
22 - 36
40 - 66
64 - 104
40 in. Triple Coulter
2.5 - 4.1
4.7 - 7.7
7.1 - 12
14 - 23
21 - 34
38 - 63
60 - 99
30 in. Double/TR Coulter
2.2 - 3.6
4.2 - 6.9
6.3 - 10
12 - 20
19 - 30
34 - 56
54 - 88
38 in. Double/TR Coulter
1.8 - 2.9
3.3 - 5.4
5.0 - 8.1
9.7 - 16
15 - 24
27 - 44
42 - 69
40 in. Double/TR Coulter
1.7 - 2.7
3.2 - 5.2
4.7 - 7.7
9.2 - 15
14 - 23
26 - 42
40 - 66
30 in. Single Coulter
1.1 - 1.8
2.1 - 3.4
3.2 - 5.2
6.1 - 10
9.3 - 15
17 - 28
27 - 44
38 in. Single Coulter
0.9 - 1.4
1.7 - 2.7
2.5 - 4.1
4.8 - 7.9
7.3 - 12
13 - 22
21 - 35
40 in. Single Coulter
0.8 - 1.4
1.6 - 2.6
2.4 - 3.9
4.6 - 7.5
7.0 - 11
13 - 21
20 - 33
* These sizes standard in most Great Plains fertilizer systems.
31014E