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Organic Alfalfa

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					Organic Alfalfa Production



Bruce Bosley
CSU Extension Agent/
Cropping Systems & Natural Resources
Lower South Platte
Alfalfa Benefits in a Crop Rotation

  Perennial crops develop soil conditioning
     Enhanced soil structure
     Macropores are established resulting in:
        Enhanced soil aeration and water
         infiltration rates
     Create a favorable habitat for many
      beneficial soil micro-organisms
Alfalfa Benefits II

   Provides a favorable habitat for beneficial
    arthropods, pollinators, and natural pest
    enemies.
   As a result there are few serious pests in
    alfalfa
Alfalfa Benefits III

  Nitrogen fixing plant
    Can credit over 100 lbs N for next
     year’s crop and 50 lbs N for the year
     after that
  Nitrogen scavenger
    Can pick up nitrogen that has moved
     below the root zone of other rotational
     crops – to 10 feet and beyond in deep
     soils
Alfalfa Benefits IV

  Increase livestock performance (output) in
   grazed pastures
    Higher protein forage
    Expands mineral content of diet (deep roots)
    Have to manage for Bloat
       Increased performance usually outweighs risks
       Depends on the manager’s risk tolerance
 Alfalfa and Perennial Pastures fit
 Uncertain water situations
 Alfalfa and perennial forages are the best fit
  for uncertain irrigation supplies
   More reliable
                                               6
   Adapted to                                 5




                           Yield (tons/acre)
  precipitation                                4

                                               3

  seasonality                                  2

                                               1
      Dormancy survival                       0
                                                   3   6   9   12   15    18    21   24   27   30

                                                               Water use (acre-in)
Alfalfa Requirements
  High Phosphorus and Potassium feeder
  More seasonal work
     3, 4, or 5 cuttings
     Irrigation from March to October
     Manual stacking of small bales
  Haying equipment (different from row crops)
  Equipment for hauling hay to market
     Swather, windrow inverter, bailer, stacker
  Tarp or shed for covering bales
Organic Production

  Similar to Conventional - Exceptions:
    Requires Federal Certification to call it Organic
    Organic seed (if available - must document)
       Untreated seed
       Non-GMO (no use of Roudup-ready alfalfa)
    Organic Fertilizer sources
    Biointensive IPM for Pest Management
       (Pests = Insects, weeds, diseases, rodents, etc)
Excellent Pest Tolerance starts
with Healthy Alfalfa
    Seed for a dense stand
    Well drained site with productive soil
    Fertilize based on soil & water test levels
    Seed at12 to 15 lbs PLS./acre – preferably drilled
      Firm and pest free seed bed (all pests)
      Appropriately timed – Front range & High plains
          April 10th to 20th & August 15th to Sept 5th
  Manage for stand health
  Remove weak stands
Manage for Stand Health
  Understand risks of tillage, compaction, &
   overwatering & poor drainage
    Tillage causes crown injury and allows soil
     diseases to infect plant
       Injury directly proportional to degree of tillage
       crown rot: the primary cause of alfalfa stand loss
    Compaction limits root development and
     increases chances for water-logging soils
    Standing water and saturated soils kill alfalfa
       Diseases & direct drowning of roots & crowns
Experience with Alfalfa Health

  Some farmers find that healthier alfalfa
   stands are less likely to be damaged by
   weevils
  Some even use refractometers to monitor
   alfalfa plant health
    Refractometers index plant sugar levels
       “equivalent to taking a plant’s pulse rate and blood
        pressure”
Biointensive IPM for Alfalfa

  Biointensive IPM incorporates ecological and
   economic factors into agricultural system
   design and decision making.
  In doing so, it addresses public concerns
   about environmental quality and food safety.
Biointensive IPM addresses the
following questions:
  Why is the pest there?
  How did it arrive?
  Why doesn’t the parasite/predator complex
   control the pest?
  What pest management techniques are most
   suited to protecting the crop and restoring the
   natural Agroecosystem to a natural balance
   with the lowest monetary and environmental
   costs?
Biointensive IPM for alfalfa

  Insect Pests
  Diseases
    Root and Crown Diseases
  Vertebrate Pests
  Weed Management
Management of Alfalfa Insects

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             >
Alfalfa Insect (arthropod) Pests
    (In order of concern in Colorado)
  Alfalfa Weevil
  Army Cutworm
  Other incidental Arthropod pests
      Caterpillars
      Aphids
      Leafhoppers
      Two spotted mite
      Blister Beetle
Alfalfa Weevil Biointensive IPM

  Maintain high beneficial populations for
   controlling weevils
  Alfalfa is an ideal crop for a pest
   management system that doesn’t
   completely eliminate the pest but simply
   reduces it’s population to a moderate
   level
  Alfalfa weevil is generally a 1st cutting
   threat
Alfalfa Weevil (continued)
  Harvest first cutting early to avoid increasing
   feeding damage as weevil larvae grow
    Cut and remove quickly (haylage). Solarization
    Graze off at bud stage (consume & solarize)
       Can also reduce cool season weeds
  Mix alfalfa with grass to reduce impact and
   enhance beneficial populations
  Harvesting alternative strips dramatically
   increases the beneficial populations
Alfalfa Weevil (continued)

  Flaming alfalfa can complement weevil
   management and reduce winter annual
   weeds.

  Timing:
    Early Spring near dormancy break
    Mid spring growth (following a very early cut)
    Following first cutting harvest
Alfalfa Weevil (continued):
    Flaming
  Kansas study:
    Flaming alfalfa reduced weevil larvae from 2.2 to
     0.3 per stem in the first year and 2.7 to 0.9 the
     second year of the study
  California study:
    In addition to weevil control, flaming alfalfa can
     reduce weed levels: 75% tansy mustard &
     shepherds purse at 22 gallons propane per acre &
     50% at 11 gallons per acre
Alfalfa Weevil (continued)
  One recommendation is to take the last
   cutting of alfalfa as late in the season as
   possible. This “may” reduce weevil damage
   on the next crop
  Another is to graze off top growth well after
   freezing.
  However, both techniques can reduce winter
   hardiness. (rebuild plant energy, trap
   moisture & even out soil temperature
   fluctuations in the winter)
Alfalfa Weevil (continued)

  Adult weevils overwinter in alfalfa fields &
   adjacent field margins and grass areas
  Release of biocontrols for alfalfa weevil
    New released biocontrol agents often take at
     least three years to bring prey under control
    Try to conserve natural beneficial
     populations in and around field margins
    Bathyplectes curculionis is very effective in
     the West
Alfalfa Weevil (continued)

  Natural pesticides for alfalfa weevil control
    Neem – acting as a toxicant, insect growth
     regulator, and antifeedant.
    Neem worked in caged tests in fields
       2.5% and 5% seed suspensions applied four times at
        weekly intervals completely interrupted the larval
        development of the weevil pest and increased yields
Consider organic pesticide
use as one tool and normally
the one of “last resort”

Any pesticide, including organics, can
disrupt the natural balance between pest
and beneficial populations
Army Cutworm
  Night feeding (will climb and defoliate)
    Rests under ground near crown during day
    Cutworms have many natural predators and
     parasites
  Apply “natural pesticides” at night
      BT spray or BT Baits (rolled oats & molasses)
      Thyme’s essential oils
      Neemix Botanical Insecticide
      Others (Check Colorado Licensing of these
       products)
Incidental arthropod pests

  Most of the listed incidental pests have plenty
   of natural enemies and are rarely encountered
   in Colorado
  Enhance beneficial populations (easier to
   accomplish in organic fields than in
   conventional)
  Harvest early to remove pest threat
Blister Beetle

  Second and later cutting pest affecting horses
  Considered beneficial since larvae feed
   primarily on grasshopper eggs
  Adults are attracted to flowering crop or
   flowering weeds in or near crop margin
    Harvest before bloom and control weeds
  Adults mass on a few plants in a small area
    Concentrated in one or a few bales
Alfalfa Diseases
  Soil health management is the key to
   successful control of plant diseases
    Soil borne diseases are the primary Colorado
     alfalfa problems
    Stem nematode near soil surface.
  Diseases occur when:
    The pathogen is present
    The host is susceptible
    And the environment is favorable
The Health Triad

 Organism
   Inherent Strengths & Weaknesses
 Environment
 Condition (degree of fitness)
   Energy and Resilience
   Pests
   Abiotic Injuries
Post-Emergence Seedling Blight




                            Photo by Craig Grau
Seedling Blight Management

   Field selection: avoid poorly drained areas
   Phytophthora resistance
   Avoid irrigating during emergence
   Plant in spring?
     Pythium favored by cool/warm, wet soil
Phytophthora Root Rot
Root Rot Management

  Don’t cut too often       Variety resistance to
  Don’t cut in late fall     AN, APH, PRR, winter
                              hardiness
   until after hard frost
                             Field selection
  Insect control
                             Balanced fertility
  Avoid traffic on          Crop rotation
   crowns
                             Proper irrigation
  Do not cultivate
      Crown & Root Rots


Fusarium crown & root rot:
  - Greatest impact on stand persistance.
  - wet field conditions/heavy equipment,
    weather (too wet/too dry, freezing/thawing)
    insect damage, tillage for weed control
Anthracnose:
  - Stem & crown lesions.
  - Plants can have individual stem die back.
  Fusarium Root & Crown Rot


Photo by APS
Anthracnose




              Photos by APS
Anthracnose




              Photo by Bill Willis
         Alfalfa Wilt Diseases

Vascular wilt diseases:
  - Damage/discoloration of water conducting tissue.
  - Culturing required for ID.
Bacterial wilt:
  - Formerly devastating in Colorado
  - Resistant varieties
Verticillium wilt:
  - Occasional problem in select fields
  - Resistant varieties
Fusarium wilt:
  - Resistant varieties
Bacterial Wilt
  Verticillium Wilt




Photo by B. Pennypacker
Fusarium Wilt
Stem Nematode

                        Internodes stunted
                        Swollen nodes
                        Twisted, crinkled,
                         yellowed or white
                         leaves
                        Growths die
                        Use a resistant
                         variety

Photo by Bill Willis
Foliar diseases - Spring Blackstem




             Photo by APS
Vertebrate Pest Management

  Pocket Gopher (# 1 pest of all forages)
    Especially on Sandy Fields
  Controls include:
    trapping, flooding, planting field edges with
     repellent plants (gopher spurge, castor bean)
    Predator Urine in the burrows
    Owl perches (barn owls eat 155 gophers/year)
    Propane exploders – check regulations &
     efficacy?
Other vertebrates

  Voles, Ground Squirrels, Rabbits, Deer
  Controls:
      Keeping field edge vegetation short
      Fencing
      Trapping rodents
      Providing predator perches & blind
      Repellants & frightening devices (efficacy?)
Weed control in organic Alfalfa

    Use Alfalfa’s competitiveness
    Natural in healthy perennial communities
    Easier in a mixed alfalfa/grass mix
    Manage crop health to enhance competition
Manage crop health to enhance
Alfalfa competitiveness
    Seed for dense stand establishment
         Fall plantings are inherently more successful
    Pay attention to fall health
         irrigation & time for plant regrowth after last cutting
      Use cutting frequency appropriate to hay market
      Avoid traffic induced crown damage
      Eliminate/reduce crown injury from tillage
      Promote good alfalfa growth through fertility,
       irrigation, and harvest management
Seeding competitive alfalfa/grass

  Seed alfalfa at 8 to 10 lbs/acre for hay
  Seed alfalfa at 2 lbs /acre for grazing
  Cut Seeding rate of perennial grasses
   appropriate to the use (60% or full)
Using oat or barley nurse crop

  Seed 1 bushel of oats (32 lbs)
  Seed 1 bushel of barley (64 lbs)
  Harvest these nurse crops prior to
   heading (boot stage or earlier)
  Irrigate to avoid drought stressing alfalfa
    Small grains can take the majority of soil
     water, especially in the fall.
Plant alfalfa in weed free fields

  Clean fields are essential with “solo” alfalfa
   seedings
  Nearly as important with nurse crop plantings
  Pre-plan and manage weeds (gophers) in
   previous crops
  Use tillage or burning to eliminate weeds
   prior to planting
    Both practices “burn off” soil organic matter
Natural Stand Decline

  Alfalfa stands naturally thin out with age
    2 to 4 productive years are common
     especially with intensive dairy hay cropping
  Know when to take out an unproductive
   alfalfa stand
  A weedy stand usually indicates when it’s
   time to rotate to another crop
Determining When to Eliminate
an Alfalfa Stand
When & How?

  The best time is in the fall after the final cut
   but any time will do.
  Make the counts after 4 to 6 inch re-growth
  Make several (10 to 20) random stand counts
   throughout the field
  Pre determine your threshold level
    <40 to 45 plants per square foot are
     recommended.
Stands should also be evaluated
for disease, weed, and gophers
  Eliminate a stand if severe crown rot is
   common
  Eliminate stands if significant stem nematode
   infestations are present
  Mustards and dandilion may be influential
  Gophers and other rodents may also
   determine whether to keep a stand
Irrigated Pasture Grazing
  A discussion for
   another day and time
     Contact me later
    Bruce Bosley
    bruce.bosley@colostate.edu
    Office phone:
    (970)522-3200, x 285
Seeding & Growing for Alfalfa
Health
Site Suitability

  Alfalfa grown on subirrigated sites should
   have permanently wet soil at least 3 feet, and
   preferably 6 or more feet, below the soil
   surface.
  Avoid poorly drained soils or those with high
   water tables
  Alfalfa is also poorly suited for saline or
   shallow soils
Soil Fertility

  Most soils in Colorado need phosphorus
  Manure and Compost are excellent sources
  Not all Organic phosphorus sources are plant
   available in Western high pH soils
  Phosphorus fertilizers can be broadcast and
   incorporated prior to seeding
  Top-dressed applications on standing forages
   are useful but not as available as incorporated
Soil Fertility (cont)

  Nitrogen is generally not beneficial to alfalfa.
  10 to 15 pounds N can enhance sandy soil
   alfalfa establishment. (manure & compost)
  Check for Nitrogen in Irrigation Water
Soil Fertility (cont)

  Check K, Fe, Zn, B levels in soil
  Check for Boron levels in Irrigation Water
  These are found in Manure & compost
    Organic matter provides natural chelates for
     keeping the fertilizer elements from being tied up
     in high (or low) pH soils.
Alfalfa Seeding - Seedbeds

  Alfalfa seeds need good soil contact and soil
   moisture for rapid emergence
  Footprints should sink in about 1/2 inch with
   a well packed alfalfa seedbed
  No-till and reduced tilled seedbeds are useful
   with the right planter and right planting pre-
   planning and residue management
No-till & stubble plantings
  Plant residue or stubble can be used effectively to
   minimize erosion.
  No-till seeding into small grain stubble can be
   particularly effective.
  Annual weeds and volunteer grains must be
   eliminated prior to seeding (sweeps or flaming)
  use special no-till drills to seed into small grain
   stubble
  Excessive straw confounds stubble seeding
Reduced and no-till alfalfa plantings
require good pre-planning

  Crop preceding alfalfa must fit the tillage
   plan
  Residue management needs considering
  Should pre-fertilize for the alfalfa crop prior
   to planting the “bridge” crop especially when
   turning under manure and/or compost.
  Manage alfalfa weeds and rodents in previous
   crops
Reduced tillage drills

  The Most reliable seeding method uses a drill
   equipped with depth bands and packer wheels.
     Good on most field sites and conditions.
  Or use seeding equipment that places seed between
   two corrugated rollers
     Best Suited to:
        fine-textured soils
        With good moisture retention
        Not on erosive sites/soils.
Use of Companion Crop

  Companion crops also reduce the hazard of
   erosion but must be removed before they
   compete with new alfalfa seedlings
  Harvest companion small grain at or before
   boot stage
  Use only when protection is needed!
Companion Crops
  Companion crops compete with alfalfa seedlings for light,
   moisture, and soil nutrients
  Small grain companion crops should be harvested as forage
   no later than the boot stage.
  Waiting to harvest grain from companion crops risks stand
   loss of alfalfa.
  Oats are an excellent companion crop for fall- or spring-
   seeded alfalfa.
  Seed only 15 to 20 pounds of oats per acre
  Only use oats that are free of weed seed.
  Wheat, rye, and barley are often too competitive
Seeding depth

  Seed alfalfa 1/4 to 1/2 inch deep in fine
   textured soils and 3/4 inch deep in sandy soils
  Many alfalfa seedings fail because of
   planting too deep
  Some fail due to poor moisture conditions or
   surface crusting
    Rectify this with high residue plantings
Seeding Rates

  12 to 14 lbs per acre on irrigated fields
  8 to 10 lbs/acre on dryland fields
  Use lower rates when mixing with perennial
   cool season grass mixtures
  Inoculate seed where no alfalfa has been
   grown in the past (>10 years)
Planting Dates

  Seed alfalfa between April 15 and May 5
  August seeding can succeed if soil moisture
   is favorable
  Weeds can be a problem for spring seeding
  August seeding avoids most weed problems
    Dryland seeding is more risky due to potential
     for lack of adequate rainfall
Avoid Frost and Drought
  Frost damage is minimized by planting within these
   recommended planting dates.
  Early Seedlings are frost resistant
     Emergence through cotyledon stage
  Seedlings are frost susceptible until the third
   trifoliate leaf is formed
     1st trifoliate and 2nd trifoliate stage don’t have enough
      crown energy reserves
  Drought stress is more often the cause of dryland
   planting failures
Delay harvest on Newly
Established Alfalfa Stands
  Do not harvest alfalfa seeded in August until
   the following spring.
  Allow spring and August seedings to start to
   bloom before the first harvest.
  Thereafter, harvest at 1/10 bloom
Soil Compaction

  Alfalfa production develops soil structure
  Soil Structural Strength can be dense but is
   not necessarily compacted
  Compaction studies in Alfalfa have not
   shown conclusive evidence that in-crop
   efforts at removing compaction are effective
  Don’t compact in the first place
    Keep off wet fields when possible

				
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