MSU Forage

SOIL NUTRIENT
MANAGEMENT
FOR FORAGES

NITROGEN

Kathrin Olson-Rutz Research Associate
Clain Jones Extension Soil Fertility Specialist
Department of Land Resources and Environmental Sciences, Montana State University - Bozeman

reprinted 2015 EB0216

INTRODUCTION
Forage crops provide substantial income to many
Montana farmers. They are also an integral part of
livestock production systems, where winter feed can
be the largest annual production cost on ranching
operations (1). Improvements in forage production
through improved soil fertility practices have the
potential to increase income and reduce livestock
production costs.
An important step towards soil fertility is nurturing
soil health. In forage production this includes: allowing
adequate plant recovery time, encouraging plant species
diversity, and leaving cover and standing material to
buffer changes in soil temperature and help store water.
These may increase soil organic matter, aggregation,
nutrient availability, plant resistance to stresses, and
yield. Contact the National Resources Conservation
Service (NRCS) for more information on management
for soil health.
This bulletin focuses on using legumes or other
sources of nitrogen (N) for established perennial forage
stands. Newly seeded perennial stands and annual forage
crops require slightly different N management and will
be discussed briefly. Soil phosphorus (P), potassium (K),
sulfur (S) and micronutrient management practices for
forage crops are presented in EB0217. For additional
information on plant nutrition, soil fertility, and N
cycling, see MT4449-2 and MT4449-3. For information
on species composition and grazing management
see EB0019 and EB0099. These and other resources
mentioned in this bulletin are listed under “For more
information” at the end of this bulletin.

© 2015
EB0216
The U.S. Department of Agriculture
(USDA), Montana State University and
Montana State University Extension
prohibit discrimination in all of their
programs and activities on the basis
of race, color, national origin, gender,
religion, age, disability, political beliefs,
sexual orientation, and marital and
family status. Issued in furtherance of
cooperative Extension work in agriculture
and home economics, acts of May 8 and
June 30, 1914, in cooperation with the
U.S. Department of Agriculture, Jill Martz,
Director of Extension, Montana State
University, Bozeman, MT 59717.

cover photo by Julianne Sather
1

EMERGENCE (% of 0N control)

100
80
60
40
20
0

0

27

53

107

107

- - - - - - - - - - - - - - - - Seed-placed - - - - - - - - - - - - - - - - B'cast-incorp.
N RATE (lb N/acre) AND PLACEMENT

FIGURE 1. Timothy seedling emergence declined with increased rate
of seed-placed N and was not affected by broadcast-incorporated N.
Brandon, Manitoba (2).

Of the 17 chemical elements that are essential for plant
growth, N is the nutrient that most often limits grass
growth. Nitrogen is very mobile in the soil and can
become limiting in areas with high rainfall or irrigation,
in coarse or shallow soils, and in soils with low organic
matter. Nitrogen is lost by leaching, to the atmosphere,
and by removal at harvest.
The key to N management for optimal forage yield
and quality is to select the right fertilizer (or manure)
source, rate, placement, and timing for your operation
(4R Concept). These are usually interrelated; for
example, the right rate, placement, and timing are very
dependent on the source. In addition, selecting the
right crop, the best management practices to maximize
legume N fixation, and right crop rotation are also
critical. Getting it ‘right’ not only increases your bottom
line, it also protects soil, water, and air resources.
NEW OR INTERSEEDING

Nitrogen is not recommended when direct seeding into
a stand of weeds or other undesired species because it
stimulates growth of those species. These then provide
too much competition for desired seedlings, especially
of slow- establishing perennial species. Small amounts
of N are only warranted if planting on sandy soils with
low fertility or in late summer/early fall after a cereal
grain crop, when soil available N has been depleted.
Under these circumstances, up to 60 lb N/acre may
be beneficial in the first year (EB0161), but to avoid
seedling damage, less than 10 to 15 lb N/acre should
be applied with the seed (Figure 1). Surface broadcast
N application should be postponed until after seedlings
have emerged and established secondary roots to
minimize weed competition. If soil organic matter

Manage as a
pure grass stand
emphasize N
100

Manage as a mixed stand
75

50

Manage as a pure
legume stand
emphasize P & K
25

0

GRASS COMPONENT (%)
LEGUME COMPONENT (%)
0

25

50

75

FIGURE 2. Nutrient focus depends on ratio of grass to legumes in the
stand. Adapted from 3.

100

is greater than 3 percent, then decomposition of the
organic matter may reduce the amount of N fertilizer
required for 2 to 3 years.
ESTABLISHED STANDS

Maintaining forage stands and improving old stands
with fertilizer is more effective than mechanical
methods (aeration, harrowing and light disking) and less
expensive than reseeding. However, fertilizing stands
that have more undesirable than desirable species may
increase production of the undesirable species. Weed
control measures should be implemented near time of
fertilization to maximize the return.
The proportion of grass to legumes in the field
determines whether fertilization should focus on N or P
and K (Figure 2). Fertilizing stands containing legumes
with N will reduce the legume population and favor
grass (Figure 3). Forage stands containing greater than
50 percent legume may respond little to applied N if soil
conditions are suitable for N-fixation. Legumes require
species-specific soil bacteria (rhizobia), which prefer soil
pH higher than 6. They also require adequate P, K, S
and micronutrients for healthy N-fixation (see EB0217).
Yield increases and net returns from applied N have
been found to be highest in fields with low percentages
(less than 36 percent) of alfalfa and low levels of soil
nitrate-N (5 lb N/acre; 5).
Source The most common sources of commercial
fertilizer N are urea and urea ammonium nitrate (UAN).
These are also available as ‘enhanced efficiency fertilizers’
designed to reduce N losses and increase N availability
(see EB0188).

PERCENT CLOVER (dry matter)

NUTRIENT MANAGEMENT

50
45
40
35
30
25
20
15
10
5
0

A

AB
AB

BC

AB

CD
D
K+B+Ca+S K
P
None Manure N+P+K
N
- - - - - - - - - No N - - - - - - - - ---------N----------

FIGURE 3. Clover biomass in a mixed stand was highest without N and
lowest with 3 years of N fertilizer. Bars that have none of the same
letters are different with 95% confidence. Marshfield, Wisconsin (4).

NITROGEN 2

Unincorporated urea is more susceptible to
volatilization loss than UAN (see EB0209). However,
urea and ammonium-based fertilizers are less likely
to accumulate as toxic nitrate in forage than nitratecontaining fertilizers (5). The source should be selected
based on cost per pound of available N, ease of
application, potential germination issues if applied with
the seed, and potential for high nitrate in plant tissue.
Nitrogen sources that need to decompose or break
down in the soil to become plant available (manure
or fertilizers that are polymer coated) will have a lag
effect before the forage responds. They may provide
N too late to stimulate early growth, or in areas with
a short growing season. For example, in west-central
Alberta, spring-applied polymer-coated urea consistently
produced less forage than urea broadcast on bromegrass
pasture (6). However, slowly available N sources can
extend benefits for season-long pasture or a late cutting.
If available, manure is a good source of N. However,
fresh manure solids containing substantial straw (C:N
greater than 40:1) may actually tie up N for a few weeks
as they begin to decompose, and the amount of plant
available N released may not peak until 2 to 3 years after
application (see EB0200). Because manure nutrient
content is highly variable, test the manure and soil for
available N content to calculate application rates that
meet crop needs (see 'Manure management resources'
under 'For more information'). Be aware that manure
can contain viable weed seeds or herbicide residues toxic
to certain forage species.
Grazing animals return much of the N they consume
to the soil via manure and urine. However, there is

some N loss through cow weight gain and volatilization,
and N can be redistributed from grazing areas to near
corners, fences, and water. This can eventually lead to N
deficiency in preferred grazing locations (7).
Interseeded legumes are an excellent source of N and
improve forage quality. In a Wyoming study, irrigated
grass-alfalfa mixes had higher yield than either pure grass
with 134 lb N/acre or pure alfalfa without N, and similar
crude protein to pure alfalfa (8). In southcentral Alberta,
pure bromegrass dry matter yields required 90 lb N/acre
annually to equal the yields of pure alfalfa fields without
N (Figure 4). Forage stands with 33 to 66 percent alfalfa
and no additional N yielded about the same as pure grass
stands with 135 lb N/acre annually. In this three-year
study, protein content, net margins, and hay produced
per unit of energy input were greater from grass-alfalfa
mixtures than from pure grass (9).
Interseeded legumes, as well as manure, contribute
N that benefits yield and protein content throughout
the growing season, rather than in a single flush (10,
11). For a summary of using legumes and manure as
nutrient sources, see EB0200 and 'Manure management
resources' under 'For more information'.
Rate Base N rate on soil tests, the expected yield
and the percentage of legume in the stand (Table 1).
Soil tests from samples taken in the spring rather than
fall usually better reflect N available to the crop in
that growing season because of overwinter soil nitrate
changes (13).
5.0

Oahe intermediate wheatgrass
Luna pubescent wheatgrass
Manchar smooth brome

4.5
4.0
3.5

6
5
4
Pure alfalfa
66 alfalfa/33 grass
50 alfalfa/50 grass
33 alfalfa/66 grass
Pure grass

3
2
1
0

0

45
90
135
ANNUAL N ADDED (lb/acre)

180

FIGURE 4. At least 33 percent alfalfa in a bromegrass/alfalfa field with
no N fertilizer produced similar yields to straight bromegrass receiving
135 lb N/acre applied annually. Eckville, Alberta (9).

3

YIELD (ton/acre)

DRY MATTER YIELD (ton/acre)

7

3.0
2.5

}

rhizomatous

}

bunch

2.0
1.5
Hycrest crested wheatgrass
Paddock meadow brome
Bozoisky Russian wildrye

1.0
0.5
0.0

0

50

100
150
N RATE (lb N/acre)

200

250

FIGURE 5. Rhizomatous (sod-forming) grasses yielded more in response
to increased N rates than bunchgrasses. All were grown in Buffalo,
Wyoming, with flood irrigation (14).

Generally, soil N in grass-dominated stands managed
for hay is low because the stands remain undisturbed
(untilled), thus releasing little N by organic matter
decomposition. Adding N can increase yield of a vigorous
grass stand if water is not limiting. Higher yielding grass
species generally respond more to increasing N than
lower yielding species adapted to low rainfall (Figure 5).
However, as yield increases, grass digestibility decreases
and protein content may decrease, unless N is added
above generally economically viable rates (60 to 80 lb
N/acre; 15). Fertilizing at high rates to increase grass
protein increases the risks of high forage nitrate levels and
downward movement of nitrate-N below the root zone.
Forage nitrate toxicity may occur at N rates well
below those that maximize production (Figure 6).
The tendency of grasses to accumulate nitrate varies
with grass species and maturity (17). Of cereal forages
tested in Montana and Wyoming, oat accumulated
the most nitrate in high nitrate environments, spring
wheat and triticale the least, and barley and spelt nitrate
accumulation were very variety dependent. Nitrate
concentrations decreased from flowering to soft dough
stage in all species, suggesting delaying harvest may be
worthwhile in high N environments, especially with
nitrate-accumulating varieties (18). Check with your
Range or Livestock Extension Specialist for species
suitable for certain production systems, and talk to
your Extension agent about conducting a quick test to
determine if your forage has high nitrate.
Visual N deficiency symptoms can be used to manage
N. Nitrogen deficient plants have uniformly yellow
or light green lower leaves (see MT4449-9). However,
4.0
TOTAL ANNUAL YIELD (ton/acre)

1.5

2.5
2.0

1.0

1.5

non-bred animals

1.0

0

50

Yield
Potential
(ton/acre)2

80/20

1
2
3
4
5
6

5
10
15
20
25
30

Alfalfa/Grass
60/40
40/60 20/80
available N need (lb/acre)3
10
15
20
20
30
40
30
45
60
40
60
80
50
75
1004
60
90
1204

0/100
25
50
75
1004
1254
1504

From EB0161; 2 Attainable yield when all growth factors optimized; 3 Fertilizer N =
available N – soil nitrate-N from soil test; 4 Do not exceed 100 lb N/acre in a single
application on cool season grasses (12).

0.5

TABLE 2. Plant part to sample, sampling time and critical N
concentrations for plant tissue from alfalfa and grass1.

pregnant animals

0.5
0.0

TABLE 1. Nitrogen fertilizer guidelines for alfalfa and grass in Montana
based on soil nitrate analysis, yield potential and alfalfa/grass mix1.

1

FORAGE NITRATE (%)

3.0

Special considerations:
Cereal forages – Growing cereal forages in rotation with
perennial forages helps eliminate weeds and disease
problems in the perennial rotation. Cereal forages can
also relieve grazing pressure from perennial pastures or
be baled for hay.
Preliminary field trials near Huntley and Froid,
Montana, indicate dryland Willow Creek winter
wheat requires 14 to 27 lb available N in the upper
2 feet of soil per ton of forage, while dryland barley
requires 30 to 64 lb available N/ton of forage to
maximize yield (20, 21, 22). These rates are based on
fall soil tests. Because winter wheat establishes earlier
and roots deeper than barley, its total N use is likely
higher than the 14 to 27 lb N/ton measured, since it
can scavenge deep soil N.

2.0

Yield
Nitrate
Limit forage intake

3.5

be cautious of pseudo-deficiencies, such as disease or
herbicide damage that may look like N deficiency. Once
plants are light green or yellow, potential yield has likely
already been reduced. Therefore, it is better to rely on
soil test recommendations, N removal rates, or tissue N
concentrations (Table 2).

100
150
200
250
ANNUAL N RATE (lb N/acre)

300

0.0

Crop

Plant part

Stage

N concentration(%)2

Alfalfa

Leaves from top
third of plant

Bud to 10%
bloom

3.75-5.50

Grass

Uppermost leaves

Right before
heading

3.20-4.20

Abbreviated from 19; 2 Nutrient concentration range is valid only for the crop, plant
part, and sampling time indicated.

1

FIGURE 6. Nitrates in bromegrass reached levels toxic to livestock at N
rates less than rates which maximized production. Nitrate-N = nitrate x
0.23. Vimy, Alberta (16, MT200505AG).

NITROGEN 4

Mountain meadows – Based on several mountain
meadow studies in Colorado, forage yield per
pound of N is highest around fertilization with 40
to 60 lb N/acre. Higher N rates may reduce forage
protein and digestibility and increase lodging (23).
Meadows flooded during part of the growing season
and dominated by a dense thatch of sod have lower
production response and recovery of fertilizer N than
meadows on mineral soils. On these high organic
soils, forage yields may decline for several years after
N fertilization is discontinued. Once a fertilizer
program is started, it is suggested to continue without
interruption to maintain higher yields. Consider
applying N on small test strips to evaluate a given
field’s response to N fertilizer (24).
Native rangeland - Nitrogen fertilization of native
rangelands provides a long-term residual effect (25).
Although this may appear desirable, researchers
from Montana, Colorado and Wyoming suggest
caution because species composition may change to
the detriment of the native plant community (15,
26, 27). Weed monitoring is very important on
fertilized native range because there are few remedial
options. Also, the costs of N fertilization or legume
interseeding may be excessive.
Timing and Frequency Timing of N fertilization
depends on the N source and soil and climatic
conditions which influence how quickly N becomes
available from soil organic matter. Sources that slowly
release N over time (e.g. slow- or controlled-release
fertilizer, or manure) should be applied well before N is
needed.

Sources that supply readily available N should be
applied before the rapid increase in plant N uptake
(Figure 7). This ensures adequate N for rapid growth
and increases N recovery with fewer losses. Cool season
grasses start rapid N uptake at jointing, therefore apply
N in the spring shortly after green-up. If possible,
time application so it can be incorporated with at least
½-inch of irrigation or rainfall in a single event to
minimize volatilization loss and increase N recovery
(Figure 8). Applying urea in fall under cool temperatures
with ability to irrigate is an option. However, in soils
with high leaching potential, such as coarse or shallow
soils, fertilizer is better applied in the spring than fall
to minimize overwinter loss (see MT201103AG). Also,
fall application must be early enough that roots are still
taking up N, but late enough that it does not stimulate
leaf growth, which decreases winter hardiness.
Enhanced efficiency fertilizers delay the release
of urea or conversion of urea to ammonium, which
‘buys’ time for incorporation by rain or irrigation and,
therefore, gives more flexibility in application timing.
These fertilizers are discussed in the 'Source' section. See
EB0208 and EB0209 for more information.
Split N applications increase N recovery by the crop
and reduce potential water contamination. Although
split N applications may not necessarily increase yield,
they tend to distribute forage production over a longer
portion of the growing season (Figure 9). This may
increase protein in later cuttings and avoid elevated
forage nitrate levels. On fields producing multiple
cuttings, about half of the total required N is applied

100
90
80
70
60
50
40
30
20
10
0

Approximate start
of jointing stage
S uptake
N uptake
Biomass
PLANT GROWTH

FIGURE 7. Biomass and forage N and S uptake by cool season and turf
grasses in Willamette Valley, Oregon (28).

5

PERCENT RECOVERY OF APPLIED N

PERCENT OF MAXIMUM UPTAKE

60
50

A
B

40

C

C

C

C

30
20
10
0

0

1
2
4
8
16
DAYS UNTIL IRRIGATION AFTER UREA APPLICATION

FIGURE 8. Immediate application of 0.8-inch water after fertilization
results in higher N-recovery in bromegrass than when applied 2 days
later. Bars that have none of the same letters are different with 95%
confidence. Eckville, Alberta (29).

in early spring to take advantage of optimal growing
conditions and the higher yield potential of cool season
grasses; the remainder is applied after the first cutting
or mid-grazing season, or split after a first and second
cutting if a third cutting is anticipated. In years or areas
with low expected forage yields, split N applications may
not be economical.
If N deficiency symptoms are observed, in-season N
can be applied before stem elongation in grasses. After
that point, it may be too late to improve yield. Plants
that appear N deficient but do not respond to N may be
S deficient, since adequate S is necessary for N uptake.
Sulfur accumulates earlier and faster than N (Figure
7). In-season application of sulfate-S can correct S
deficiency and is discussed in EB0217.
Placement Method Application method should
maximize fertilizer uptake by the crop with minimal
disturbance to the plants. Nitrogen fertilizer applied
to thatch has high potential for N volatilization loss
(EB0208). Ammonia- and ammonium-based N fertilizer,
including manure, should be immediately incorporated
by rain or irrigation (Figure 8) or subsurface banded.
For example, a ½-inch rainfall within 3 hours of urea
application on pasture can be sufficient to protect urea
from volatilization, whereas a ½-inch of rainfall 2 days
later may not (30).

yields because there may be less volatilization loss and the
N may dissolve sooner due to subsurface soil moisture
(31). Bands should be at least 2 inches beneath the
surface and the slit produced by banding or knifing wellclosed to trap the ammonia produced by the urea band.
Foliar N is useful for in-season N adjustment if leaf
burn is minimized (see text box 'Practices that increase
the risk of leaf burn'). Because less than 16 percent of
foliar N is taken up through the leaf (36), foliar N must
be washed into the soil with at least ½-inch of water.
UAN is better applied as a surface band than a foliar
spray to increase forage yield and protein (37).

200
HAY PRICE ($/ton) TO RECOUP UREA COST

1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4

cut 3
cut 2
cut 1

0.2
0.0

- Greater than 30 lb N/acre UAN or 45 lb N/acre of liquid urea (32)
- Herbicide, fungicide, and/or surfactant plus more than 20 lb N/
acre UAN (33)
- Urea plus the urease inhibitor N-(n-butyl) thiophosphoric triamide
(NBPT; 34)
- The addition of S to liquid N fertilizer (35)
- Application during high temperature conditions
- Application later in the season (35)

Single

50/50
33/33/33
N APPLICATION DISTRIBUTION

FIGURE 9. N applied once in early spring, or split between early
spring and after the 1st or 1st and 2nd cutting on dryland bromegrass
increases total yield and improves distribution over the season. Lacombe,
Alberta (9).

160

First year @ 50 lb N/acre
4-yr avg @ 100 lb N/acre
4-yr avg @ 50 lb N/acre

115
92

120

69

80

46

40

23

0
300 400

500 600 700 800
COST OF UREA ($/ton)

AUM PRICE ($/AUM) TO RECOUP UREA COST

YIELD INCREASE OVER NO N CONTROL (ton/acre)

If the fertilizer will be incorporated with water, then
broadcast application is better than subsurface banding
because it is less disruptive to the stand. However, under
dry conditions subsurface banding may produce higher

Practices that increase risk of leaf burn:

0
900 1000

FIGURE 10. The price of hay or AUM necessary for the increased dryland
production from a single N application to offset the urea cost in the first
year (50 lb N/acre rate only) or summed over 4 years (50 and 100
lb N/acre rates). An AUM is 750 lb forage with 75% utilization (note,
earlier version used 50%). Text example uses $800 (dashed red line)
per ton urea. Adapted from 38, on introduced rhizomatous grasses in
Havre, Montana.

NITROGEN 6

SHOULD I FERTILIZE?
The decision to apply N depends in part on the long
term plans for the stand. If a grass-legume field will be
rotated to another crop within a year or two, consider
applying N for a higher immediate yield. However, if the
goal is to maximize time before reseeding with legumes,
consider sacrificing some yield in the short term to
concentrate on rejuvenating the legume portion of the
stand (see EB0217).
Yield increases and net returns tend to be greater
in fields with higher N deficiency, if all else is equal.
Use your typical yield estimate and a spring soil nitrate
sample (Table 1). High yielding grass species, such as
introduced rhizomatous grasses, tend to respond more
to N than bunch grasses or native species (38). Grass
varieties suited for low precipitation are generally less
able to respond to high N rates than those suited to high
precipitation (Figure 5).
Planting a legume in combination with grass to add
soil N is usually more cost-effective than N fertilization
for dryland pastures. However, the economic benefit
of N fertilization should be evaluated over several
years. On dryland introduced rhizomatous grasses near
Havre, Montana, single applications of 50 and 100 lb
N/acre increased yields by 0.09 ton/acre (180 lb/acre)
and 0.14 ton/acre (280 lb/acre), respectively, over the
unfertilized control. Four-year cumulative yield increases
were 1.1 and 1.2 ton/acre for the 50 and 100 lb N/acre
applications, respectively (38).
A calculation of the necessary value of additional
hay or animal unit month (AUM) produced to offset
the urea fertilizer cost only (Figure 10) in the Havre
study illustrates: 1) the 50 lb N/acre rate is more likely
to provide a positive economic return than the 100 lb
N/acre rate, 2) the economic benefit is greater when
averaged over four years than just the first year, and 3)
fertilizing is generally a better option than buying hay or
renting pasture, especially if it alleviates a chronic bottle
neck in the production system. Urea could cost $800/
ton and a single 50 lb N/acre application would still be
less expensive than buying hay (unless hay costs less than
$40/ton). Pasture rent could reach $23/AUM for each
of 4 years before it costs more than the $800 invested
in urea fertilizer to produce the equivalent additional
AUMs.

7

The economic break-even point for fertilizing
introduced bunch and native grasses averaged over
4 years (data not shown) were very similar to those
of introduced rhizomatous grasses in the first year
(uppermost line in Figure 10). Fertilizing introduced
bunch and native grasses may be an economical
alternative to buying hay, but more likely more expensive
than renting pasture. However, this does not take into
account all costs associated with fertilizing, or providing
hay or pasture, and, ultimately nutrients removed from a
field need to be replaced to sustain forage production.
The N needed to optimize profit will vary for each
production system depending on soil, other limiting
factors like water and P, hay prices, and fertilizer N
costs. As production intensity increases, so will the need
for fertilizers to maintain production levels. Efficient
fertilizer use is important in balancing productivity and
the bottom line.

SUMMARY
Nitrogen is the most common nutrient that needs
to be added for production of forages containing a
low percentage of legumes. However, N is generally
not needed at seeding or during the first year of new
dryland or irrigated perennial stands. Nitrogen is not
recommended in young alfalfa or sainfoin stands, or when
interseeding into a stand dominated by undesired species.
Readily available N sources, such as urea or UAN, should
be applied shortly after green-up or as split applications
in a manner that minimizes volatilization loss. Slowly
available N sources such as manure or slow- or controlledrelease fertilizer will have a lag effect before the forage
responds. They may provide nutrients too late in the
spring to stimulate early growth, but can extend benefits
for season-long pasture or a late cutting. Legumes may
be the most economical source of N. The proportion
of legumes in a stand will influence N fertilizer rates.
Because fertilizer N can become tied up in the soil and
plant material of perennial systems, the economic benefit
of N fertilization should be evaluated over several years.

REFERENCES
1. Nayigihugu, V., A.D. Schleicher, D.W. Koch,
L.J. Held, J.W. Flake, and B.W. Hess. 2007. Beef
cattle production, nutritional quality, and economics
of windrowed forage vs. baled hay during winter.
Agronomy Journal. 99:944-951.
2. Alberta Ag and Rural Development. 2011. Perennial
Forage Establishment in Alberta. Agdex 120/22-3.
http://www1.agric.gov.ab.ca/$department/deptdocs.
nsf/all/agdex9682
3. Flore, N. 2003. Fertility Management in Forages.
Saskatchewan Soil Conservation Association
Conference. February 19-20. Saskatoon,
Saskatchewan. pp. 78-87. http://ssca.ca/images/
pdf/2003_conference_pdf/Flore.pdf
4. Schneider, N. 2009. Soil Fertility Influences
Forage Species in Sward. http://winnebago.uwex.
edu/files/2010/09/Fertility-and-Pasture-SpeciesPersistance.pdf
5. Malhi, S.S., K.S. Gill, D.H. McCartney, and R.
Malmgren. 2004. Fertilizer management of forage
crops in the Canadian Great Plains. Recent Research
Developments in Crop Science. 1:237-271.
6. Karamanos, R.E. and F.C. Stevenson. 2013. Nitrogen
fertilizer product and timing alternatives exist for forage
production in the Peace region of Alberta. Canadian
Journal of Plant Science. 93:151-160.
7. Augustine, D.J., D.G. Milchunas, and J.D.
Derner. 2013. Spatial redistribution of nitrogen by
cattle in semiarid rangeland. Rangeland Ecology &
Management. 66:56-62.
8. Dhakal, D. and A. Islam. 2013. Legume grass
mixtures reduce nitrogen requirements and production
costs. Reflections. University of Wyoming. pp. 30-33.
www.uwyo.edu/uwexpstn/publications/reflections/
reflections-2013-web.pdf
9. Malhi, S.S., R.P. Zentner, and K. Heier. 2002.
Effectiveness of alfalfa in reducing fertilizer N input for
optimum forage yield, protein concentration, returns
and energy performance of bromegrass alfalfa mixtures.
Nutrient Cycling in Agroecosystems. 62:219-227.
10. Wagner, R.E. 1954. Legume nitrogen versus fertilizer
nitrogen in protein production of forage. Agronomy
Journal. 46:233-237.
11. Ta, T. and M. Faris. 1987. Effects of alfalfa proportions
and clipping frequencies on timothy-alfalfa mixtures. I.
Competition and yield advantages. Agronomy Journal.
97:817-820.

12. Brummer, J.E., J.G. Davis, and M.R. Booher. 2011.
Fertilizing Cool Season Grasses and Grass/Legume
Mixtures. Colorado State University Extension
No. 0.522. http://www.ext.colostate.edu/pubs/
crops/00522.html
13. Jones, C., C. Chen, J. Eckhoff, M. Greenwood, P.
Lamb, A. Lenssen, K. McVay, P. Miller, B. Stougaard,
J. Weeding, and M. Westcott. 2011. Changes in Soil
Nitrate-N Levels from Late Summer to Early Spring
in Montana. Fertilizer Fact No. 55. Montana State
University Extension, Bozeman, Montana. http://
landresources.montana.edu/fertilizerfacts/index.html
14. Horn, B. 2013. Hay study finds answer to what is
most productive. Reflections. University of Wyoming.
pp. 33-36. www.uwyo.edu/uwexpstn/publications/
reflections/reflections-2013-web.pdf
15. Brummer, J.E. Personal communication. Associate
Professor. Department of Soil and Crop Sciences,
Colorado State University, Fort Collins, Colorado.
16. Penny, D.C., S.S. Malhi, and L. Kryzanowski. 1990.
Effect of rate and source of N fertilizer on yield, quality
and N recovery of bromegrass grown for hay. Fertilizer
Research. 24:159-166.
17. Smith, A.D. and L.E. Lutwick. 1975. Effects of N
fertilizer on total-N and NO3-N content of six grass
species. Canadian Journal of Plant Science. 55:573577.
18. Westcott, M., D. Wichman, and R. Hybner. 2012.
Evaluation of Nitrate Potential in Hay from Five
Cereal Forage Species. Fertilizer Fact No. 56. Montana
State University Extension, Bozeman, Montana.
http://landresources.montana.edu/fertilizerfacts/
index.html
19. Beegle, D. 2002. Soil Fertility Management for Forage
Crops: Maintenance. Agronomy Facts 31-C. Penn
State Extension. http://extension.psu.edu/plants/
crops/forages/soil-fertility/soil-fertility-managementfor-forage-crops-maintenance
20. McVay, K.A., A. Lenssen, and C. Jones. 2012.
Cereal forage response to nitrogen fertilizer: Refining
the Montana nitrogen rate guideline. Great Plains Soil
Fertility Conference. 14:161-166. Denver, Colorado.
21. McVay, K.A. Unpublished data. Cropping System
Extension Specialist. Southern Agricultural
Experiment Station, Montana State University,
Huntley, Montana.

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22. Lenssen, A. Unpublished data. Associate Professor.
Department of Agronomy, Iowa State University,
Ames, Iowa.
23. Brummer, J.E. and N.D. Rill. 1999. Effects of Low
Rates of Nitrogen Fertilizer on Yield and Quality of
Mountain Meadow Hay. Colorado State University,
Mountain Meadow Research Center Progress
Report. February 5.

35. Phillips, S.B. and G.L. Mullins. 2004. Foliar burn
and wheat grain yield responses following topdressapplied nitrogen and sulfur fertilizers. Journal of Plant
Nutrition. 27:921–930.

24. Brummer, J.E. and J.G. Davis. 2012. Fertilizing
Mountain Meadows. Colorado State University
Extension No. 0.535. http://www.ext.colostate.edu/
pubs/crops/00535.html

36. Rawluk, C. G. Racz, and C. Grant. 2000. Uptake of
foliar or soil application of 15N-labelled urea solution at
anthesis and its affect on wheat grain yield and protein.
Canadian Journal of Plant Science. 80:331-334.

25. Power, J.F. 1972. Fate of fertilizer nitrogen applied to
a Northern Great Plains rangeland ecosystem. Journal
of Range Management. 25:367-371.

37. Kissel, D. 1988. Management of Urea Fertilizers.
North Central Regional Extension Publication 326.
Kansas State University.

26. Wichman, D. Personal communication.
Superintendent and Research Scientist. Montana
State University, Central Agricultural Research
Center, Moccasin, Montana.

38. Jacobsen, J., S. Lorbeer, H. Houlton, and G.
Carlson. 1996. Nitrogen fertilization of dryland
grasses in the Northern Great Plains. Journal of Range
Management. 49:340-345.

27. Manske, L.L. 2010. Long-term Plant Species Shift
Caused by Nitrogen Fertilization of Native Rangeland.
North Dakota State University, Dickinson Research
Extension Center. Summary Range Research Report
DREC 10-3055. Dickinson, North Dakota.

FOR MORE INFORMATION

28. Hart, J.M., D.A. Horneck, D. Peek, and W. Young
III. 1989. Nitrogen and sulfur uptake for cool season
forage and turf grass grown for seed. pp. 15-17.
In W.C. Young III (ed.) 1989 Seed Production
Research. Dept. of Crop Sci., EXT/CrS 80. Oregon
State University.
29. Malhi, S.S. 1995. Influence of source, time and
method of application, and simulated rainfall on
recovery of nitrogen fertilizers applied to bromegrass.
Nutrient Cycling in Agroecosystems. 41:1-10.
30. Black, A.S., R.R. Sherlock, and N.P. Smith. 1987.
Effect of timing of simulated rainfall on ammonia
volatilization from urea, applied to soil of varying
moisture-content. Journal of Soil Science. 38:679-687.
31. Lamond, R.E. and J.L. Moyer. 1983. Effects of knifed
vs. broadcast fertilizer placement on yield and nutrient
uptake by tall fescue. Soil Science Society of America
Journal. 47:145-149.
32. Brown, B. and L. Long. 1988. Response of ‘Ute’ to
rate and source of foliar N. Proceedings, 39th Annual
Far West Regional Fertilizer Conference. July 11-13.
Bozeman, Montana. p. 111-116.
33. Kells, J.J. 1996. Weed Management in Wheat. Wheat
Facts. Michigan State University Extension Bulletin
E2602. East Lansing, Michigan.
9

34. Krogmeier, M.J., G.W. McCarty, and J.M. Bremner.
1989. Phytotoxicity of foliar-applied urea. Proceedings
of the National Academy of Sciences, USA. 86:81898191.

MSU EXTENSION PUBLICATIONS

These, and many others, can be found by title under
'Extension Publications' at http://landresources.
montana.edu/soilfertility/, or by contacting MSU
Extension Publications at (406) 994-3273 or online at
http://store.msuextension.org.
Crop and Fertilizer Management Practices to Minimize
Leaching. MT201103AG.
Dryland Pastures in Montana and Wyoming Species
and Cultivars, Seeding Techniques and Grazing
Management. EB0019.
Enhanced Efficiency Fertilizers. EB0188.
Factors Affecting Nitrogen Fertilizer Volatilization.
EB0208.
Fertilizer Guidelines for Montana Crops. EB0161.
Management to Minimize Nitrogen Fertilizer
Volatilization. EB0209.
Nitrate Toxicity of Montana Forages. MT200505AG.
(currently out of print)
Nitrogen Cycling, Testing and Fertilizer Recommendations.
MT4449-3.
Plant Nutrient Functions and Deficiency and Toxicity
Symptoms. MT4449-9.

Plant Nutrition and Soil Fertility. MT4449-2.
Soil Nutrient Management for Forages: Phosphorus,
Potasium, Sulfur and Micronutrients. EB0217.
Soil Nutrient Management on Organic Grain Farms in
Montana. EB0200.
Species Selection, Seeding Techniques and Management of
Irrigated Pastures in Montana and Wyoming. EB0099.
MANURE MANAGEMENT RESOURCES

Fertilizing Forages with Manure. 2008. Saskatchewan
Ministry of Agriculture. http://www.agriculture.gov.
sk.ca/Default.aspx?DN=feb4e9af-8270-440d-87395bd40cb6b344
Manure and Biosolids: Regulation and Management.
MT4449-13. http://landresources.montana.edu/nm/

ACKNOWLEDGEMENTS
We thank the following for their time and expertise in
reviewing this bulletin:

-- Joe Brummer, Associate Professor, Department of Soil
and Crop Sciences, Colorado State University
-- Paul Dixon, Agriculture and Natural Resource
Specialist, Dixon Land Management, Sheridan, WY
-- Marc King, Montana State University Extension
Agent, Sweetgrass County, MT
-- Dave Wichman, Superintendent and Research
Scientist, Montana State University, Central
Agricultural Research Center, Moccasin, MT
-- MSU Extension Communications & Publications for
design and layout

Manure Nutrient Management. www.extension.org/
pages/8647/manure-nutrient-management#.
UtQXMP0ZyCz
USDA-NRCS. www.nrcs.usda.gov, search 'manure'
Using Manure as Fertilizer. EB0184. http://
landresources.montana.edu/soilfertility/documents/
PDF/pub/ManureFertEB0184.pdf
OTHER RESOURCES

Colorado Forage Guide. 2012. http://www.ext.colostate.
edu/sam/forage-guide.pdf
University of Idaho Extension. Idaho Forage Web page
http://www.extension.uidaho.edu/forage/
University of Idaho Extension. Managing Nutrients
for Forage Crops Web page http://www.extension.
uidaho.edu/nutrient/crop_nutrient/forages.html

NITROGEN 10