Managing Cultivated Forages

1
Managing Cultivated Forages

• Vance Owens and Jim Johnson

2
Cool-season grass fertility

• Nitrogen
• Highly responsive to N application
• moisture availability
• grazing versus haying
• Time of application
• apply just prior to period of most rapid growth
  (generally mid- to late-spring in SD)
• can apply in fall

3
Cool-season grass fertility

• Nitrogen
• Rate of application
• SD Fertilizer Recommendation Guide 25 lbs N per
  ton yield goal
• May do a split application (spring and fall) if
  applying more than 100 lbs/acre
• Rate decreases from east to west
• Increase rates by 50-100 under irrigation

4
Cool-season grass fertility

• Phosphorus
• Base application on soil test
• SD recommendations are 0-40 lbs P/acre depending
  on soil test
• Apply and incorporate before planting if possible

5
Impact of N rate and date of application on
crested wheatgrass yield and quality
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Nitrogen impacts on yield and protein of smooth
bromegrass at Brookings (1951)
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Age of stand and nitrogen influences on
cultivated cool season grasses
8
Twenty two year average forage yields of a smooth
bromegrass stand with 6 annual N rates at Fargo,
ND
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Twelve years of hay yields from crested
wheatgrass fertilized at four rates in Dickinson,
ND
10
The impacts of precipitation and fertilizer on
grass production at Williston, ND
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Warm-season grass fertility

• Nitrogen
• Variable response to N application
• species and cultivar
• native prairie versus seeded stands
• moisture availability
• linear to curvilinear
• grazing versus haying

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Warm-season grass fertility

• Nitrogen
• Time of application
• apply just prior to period of most rapid growth
  (generally late May in SD)
• do not apply during establishment year
• early spring or late summer encourages
  cool-season species
• Rate of application
• 25-100 lbs/acre depending on moisture and use
• Rate decreases from east to west

13
Warm-season grass fertility

• Phosphorus
• Warm-season species do better on low P soil than
  cool-season species
• Better able to use P from symbiotic relationship
  with arbuscular mycorrhizal fungi
• P application without sufficient N has actually
  led to lower yields due to N immobilization and
  microbial growth
• Nebraska recommendations are 0-40 lbs P/acre
  depending on soil test
• Apply and incorporate before planting if possible

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Response of switchgrass to N application.
Brookings County, 1975.
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Response of switchgrass to N application and
effect of carryover N (Brookings Co., 1977-1979)
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Response of big blue/indiangrass mix to N
application and effect of carryover N (Brookings
Co., 1977-1979).
17
Cost of producing extra forage using N on
warm-season grasses (Brookings, Co. 1977-79).
18
Standing crop and protein at beginning and end of
grazing trail, Norbeck FS, 1973-75
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Standing crop and protein at beginning and end of
grazing trail, Norbeck FS, 1973-75
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Grass/Legume mixtures

• Cool-season grass/legume mix most common
• Significant portion of grass N requirements can
  be met by legumes
• Application of fertilizer N increases competitive
  ability of cool-season grasses
• Application of P tends to favor legume growth
• Time of application
• apply just prior to period of most rapid growth
  (generally mid- to late-spring in SD)
• can apply in fall

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Quantity (lbs/acre/year) of N fixed by various
legume species

• Alfalfa 70-200
• Birdsfoot trefoil 45-100
• Cicer milkvetch 140
• Field peas 150-175
• Red clover 50-125
• Sweetclover 120

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Pasture renovation experiment (Greg Cuomo,
University of Minnesota-Morris).

• Initial pasture consisted primarily of Kentucky
  bluegrass, smooth bromegrass, and quackgrass
• Renovation treatments included
• untreated control
• 0.75 lbs/acre glyphosate (1 qt/A RoundUp)
  followed by interseeding in 1994 with
• 10 lbs/acre Spredor II alfalfa
• 4.5 lbs/acre each of red clover and birdsfoot
  trefoil
• Graziers mix 2.1 lbs/acre each of Vernal
  alfalfa, birdsfoot trefoil, red clover, smooth
  bromegrass, orchardgrass, timothy and 0.5
  lbs/acre each of alsike clover and ladino clover

23
Pasture renovation experiment (Greg Cuomo,
University of Minnesota-Morris).

• Cattle turned in at 10-15 inch height
• Grazed to leave 2-4, 4-6, or 6-8 inch height
• Animals grazed for 12 hours
• Published in Journal of Prod. Ag. 12564-569

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Total season forage yields of renovated pastures
at Morris, MN.
LSD (0.05) 0.48
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Total season forage yields of renovated pastures,
as a percent of the unrenovated control, at
Morris, MN.
26
Forage availability (tons/acre) by grazing date
in renovated pasture (Greg Cuomo, University of
Minnesota-Morris).
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Species composition () in renovated pasture
(Greg Cuomo, University of Minnesota-Morris).
28
Does it pay to renovate existing pastures?
29
Yield of smooth bromegrass with and without N and
grown with legumes (alfalfa and kura clover) at
Morris, MN in 1999
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Yield comparison of grass and grass-alfalfa
mixtures (tons/acre)
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Hay yields of crested wheatgrass with and without
alfalfa and not fertilized
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Hay yields of smooth bromegrass-alfalfa mixtures
compared to grass seeded alone and not fertilized
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Tips on Using Grass-Alfalfa Mixes for Pastures

• Alfalfa and cool-season grasses
• West River -- crested wheatgrass
• East River -- smooth brome, intermediate
  wheatgrass, orchardgrass
• Rotational grazing is a must to maintain alfalfa
  otherwise expect alfalfa loss in 1 or 2 yrs
• Good growing conditions graze 5-10 days, defer
  28 days before regrazing base on moisture
• Dont graze after Sept 15 allow regrowth
  cover
• Winter feeding on grass-alfalfa can damage stand
• Maintain adequate P and N. Alfalfa is equivalent
  to 50N

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To fertilize or not to fertilize cultivated grass
pastures or hayland

• Advantages
• Increased hay production
• Higher quality forage
• Increased water use efficiency
• Earlier spring growth (cool-season)
• Greater grazing capacity

• Disadvantages
• Inc. yields limited by moisture
• Annual applications generally required
• Potential for increased weed growth
• Possible ground water contamination
• Possible livestock disorders (e.g.. Grass tetany)

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Common Grass Varieties (refer to EC890)

• Cool season
• Crested wheat Nordan
• Intermediate wheat Oahe, Manska
• Reed canary Palaton, Venture
• Smooth brome Rebound, Cottonwood, Lincoln

• Warm season
• Switchgrass Neb 28, Sunburst, Forestburg
• Big blue Bonilla, Pawnee, Champ
• Indiangrass Holt, Tomahawk

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Seeding rates for pure stands of a single species
based on PLS (seeding rate goal is 20 seeds/
square foot)
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Example Calculation for a Mixed Species Seeding
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Pure Live Seed Calculation

• Smooth Bromegrass Seed Tag Information
• Pure seed 88.45 Germination 91
• Crop seed 0.12 Hard seed 0
• Inert 11.19
• Weed seed 0.24
• Calculate PLS using the following equation
• PLS ( pure seed x germ)/100
• (88.45 x 91)/100 80.48 PLS