2009-11-30_PERMIT FILE - C1981038 ‎(5)‎

• Permit No: C1981038
• IBM Index Class Name: Permit File
• Doc Date: 11/30/2009
• Doc Name: Colorado Discharge Permit ‎(NPDES)‎
• Section_Exhibit Name: Volume 7 Exhibit 05 Vegetation Data
• Media Type: D
• Archive: No

Volume 7 Exhibit 5
Table 1: Suggested N rates for new. seedings of
alfalfa.
0 -6
• irrigated
ppm NO,-N
Companion crop:
in soil
With Without
135'
Fertilizer rate, lb N/A
0 -3
60 20
4 - 6':
30 10
>6
0 0
New seedings of dryland alfalfa generally do not benefit from
prepiant N.
NOTE: Nitrogen fertilizers should not be applied to established
stands of alfalfa. N fixation activity can be decreased.
Table 2: Suggested N. rates for irrigated grasses.
ppm NQ,-N in soil Fertilizer rate, lb N/A
0 -6
185
7 -12
160
13-18
135'
19-24
110
25-30
85
> 30
0
NOTE: Use the same N rates. for grass- legume mixtures
containing less than 25 percent. legumes.
B-11 15 - 22
Table 3: Suggested P rates for irrigated alfalfa.
Table 4 :Suggested P rates for irrigated grasses,
grass- legume mixtures and pastures.
Fertilizer rate, lb P
ppm P in soil
Relative
New Established
-DTPA NaHCO,
level
seedings stands'
• AB
0-3 0 - 6
very low
200 100
4-7 7 - 14
low
150 75
B-11 15 - 22
medium
50 0
>11 > 22
!high
0 0
"Suggested. P rates for established stands should be based on
new soil test results.
Table 4 :Suggested P rates for irrigated grasses,
grass- legume mixtures and pastures.
Table 5: Suggested P rates for dryland alfalfa.
Fertilizer rate, lb P O,lA
ppm Pin Relative New Established
AB -DTPA NaHCO, level seedings stands*
0-3 0 - 6 low 60 45
4-7 7 - 14 medium 45 30
> 7 > 14 high 0 0
`Suggested P rates for established stands should be based
onnew soil test results:
NOTE: Phosphorus applications are not recommended for
.
grass-legume • mixtures and grass forages produced under
dryland conditions.
The Colorado State University Soil, Water and
Plant Testing Laboratory is located in Room A319,
Natural and Environmental. Sciences Building, Colorado
State University, Fort Collins, CO 80523; (970) 491-
5061.
Nitrogen Suggestions
Because legumes usually fix N.from the
atmosphere, some of their N requirements are met
through this process. Inoculate alfalfa with specific
.host bacteria if alfalfa has not been grown recently
in a field. However, some preplantN may be. needed
for the companion crop in the establishment of alfalfa
under irrigated conditions if residual NO N levels in
the soil are low (Table 1). Decrease the seeding.rate of
the companion crop and do not overapply N to :avoid
shading of the new alfalfa and grass seedlings,
Preplant N fertilizers generally are applied
broadcast and incorporated in combination with
P fertilizers. Application of N fertilizers in the
establishment of alfalfa is not suggested under dryland
conditions.
Grasses require annual N applications. The
suggested N rate is related to the NO N status of the
soil. Nitrogen application can increase yields of grass -.
legume mixtures, but also results.in a decline of the
legume component. Therefore, application of N to
mixtures comprised: of more than 50 percent of the
legume component is not recommended. Generally,
the proportion of legume will decline with time. Once
this.proportion reaches 25 percent or less, stands
should be fertilized with .N according to the same
recommendations given for grasses alone (Table 2).
Suggested N rates in Table 2 are for an expected yield of
4 tons.;per acre. These rates should be adiusted.by 40. lb
N/A for each ton/A difference in. expected yield.
:Phosphorus Suggestions
Irrigated Alfalfa
Alfalfa responses to applied. P are most likely
on soils with low or medium levels of extractable..P.
Suggested.P rates (Table 3) are based on broadcast
applications related to soil test Ievels. The main soil tests
for extractable P in Colorado soils are the AB -DTPA
and sodium. bicarbonate (NaHCO) tests. Values for both
tests are in Table 3.
Irrigated Grass and Grass- legume Mixtures
Table 4 gives suggested P rates for establishment
of inigated grass and grass - legume mixtures for forage
production. Broadcast and incorporate phosphate
fertilizers into the soil prior to seeding.
IqAomvle '
_g0'N0y -20W
Fertilizer rate lb P /A
ppm P - -in soil
Relative
New Established
AB -DTPA NaHCO,
level
seedings: stands'
Q.:3 0 - 6
low
80 80
4-7 7 -'14
medium
40 4o
>7 > 14
:high
0 0
'Suggested P rates for established' stands
should be based
onnew soil :test results.
Table 5: Suggested P rates for dryland alfalfa.
Fertilizer rate, lb P O,lA
ppm Pin Relative New Established
AB -DTPA NaHCO, level seedings stands*
0-3 0 - 6 low 60 45
4-7 7 - 14 medium 45 30
> 7 > 14 high 0 0
`Suggested P rates for established stands should be based
onnew soil test results:
NOTE: Phosphorus applications are not recommended for
.
grass-legume • mixtures and grass forages produced under
dryland conditions.
The Colorado State University Soil, Water and
Plant Testing Laboratory is located in Room A319,
Natural and Environmental. Sciences Building, Colorado
State University, Fort Collins, CO 80523; (970) 491-
5061.
Nitrogen Suggestions
Because legumes usually fix N.from the
atmosphere, some of their N requirements are met
through this process. Inoculate alfalfa with specific
.host bacteria if alfalfa has not been grown recently
in a field. However, some preplantN may be. needed
for the companion crop in the establishment of alfalfa
under irrigated conditions if residual NO N levels in
the soil are low (Table 1). Decrease the seeding.rate of
the companion crop and do not overapply N to :avoid
shading of the new alfalfa and grass seedlings,
Preplant N fertilizers generally are applied
broadcast and incorporated in combination with
P fertilizers. Application of N fertilizers in the
establishment of alfalfa is not suggested under dryland
conditions.
Grasses require annual N applications. The
suggested N rate is related to the NO N status of the
soil. Nitrogen application can increase yields of grass -.
legume mixtures, but also results.in a decline of the
legume component. Therefore, application of N to
mixtures comprised: of more than 50 percent of the
legume component is not recommended. Generally,
the proportion of legume will decline with time. Once
this.proportion reaches 25 percent or less, stands
should be fertilized with .N according to the same
recommendations given for grasses alone (Table 2).
Suggested N rates in Table 2 are for an expected yield of
4 tons.;per acre. These rates should be adiusted.by 40. lb
N/A for each ton/A difference in. expected yield.
:Phosphorus Suggestions
Irrigated Alfalfa
Alfalfa responses to applied. P are most likely
on soils with low or medium levels of extractable..P.
Suggested.P rates (Table 3) are based on broadcast
applications related to soil test Ievels. The main soil tests
for extractable P in Colorado soils are the AB -DTPA
and sodium. bicarbonate (NaHCO) tests. Values for both
tests are in Table 3.
Irrigated Grass and Grass- legume Mixtures
Table 4 gives suggested P rates for establishment
of inigated grass and grass - legume mixtures for forage
production. Broadcast and incorporate phosphate
fertilizers into the soil prior to seeding.
IqAomvle '
_g0'N0y -20W