CSSHRT 382 Turfgrass Physiology by ntz11397

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									ORGANIC CONTROL OF BROADLEAF
 WEED SEED GERMINATION AND
       ESTABLISHMENT


   Michigan’s Organic Agriculture Research Reporting Session

                       Suzanne Lang
                 Department of Horticulture
       What to do with leaf litter?
Clean Air Act - 1970

Federal Solid Waste Band -1995

Field Work
Nikolai & Reike - 1999

Leaf Mulch - does it hurt
  turfgrass?
Organic Control of Broadleaf Weeds in
             Turfgrass
  Field Studies

  Golf Course
 Superintendents

Kowalewski et al.
  Which Maple Leaves are Best?
Kowalewski – 2006
• Sugar Maple, High Sugar Maple, Red Maple,
  Silver Maple
• Applied at rates of 0.5, 1.0, and 1.5 kg/m-2
• Particle size ranged from 1.3 to 6.4cm

• Two successive applications of Sugar Maple at
  high application rate provide 81% control of
  dandelion (Taraxacum app.)
  Organic Control of Broadleaf Weeds in
               Turfgrass
     Pre- or Post-emergence Questions
1) Barrier Effect?
   Physically limits germination and/or
   growth?

2) Allelopathic Effect?
a) Pre-emergence
• Germination Performance
    • Germination Percentage
    • Time to Germination
b) Post-emergence
• Seedling growth
Organic Control of Broadleaf Weeds in
             Turfgrass
 Two Collection
     Events

     Summer
fresh, living leaves

        Fall
 after natural leaf
     senescence
                  Leaf Collection


  Kellogg Biological Station
     single species blocks

• Sugar Maple – Acer saccharum
• High Sugar Maple – Acer saccharum
• English Oak/White Oak – Quercus robur
  /Quercus alba
              Leaf Extraction Procedure
                    Returned to lab
                    Homogenized
                    leaves + Water

                                                          Water
                    Solution
                                 Filtered                soluble
                   [12 hours]                            extract


  Homogenized                                            Organic
                     Solution
leaves + Organic                  Filtered               soluble
     Solvent        [12 hours]                           extract


                                            6 to 7 Liters of Extract
     Leaf Extraction Procedure
                        Water                   Freeze Dry
                       soluble
                       extract
                                                  Powder
                      Organic
                      soluble
                      extract                     Storage


          Re-solublized powder at specific concentrations
Solutions can then be used for the liquid that stimulates germination



       Germination performance under controlled conditions
    Preliminary Germination Tests
    Verify Ideal Conditions

• 50 seeds/ Petri dish
• Whatmann #2 filter paper
• 2 mm double-distilled water
• Incubated at 25° C (77° F), 14
  hr day/10 hr night
• Monitored germination over
  15 days; add water as needed
       Preliminary Germination Tests

• Calculate mean time to                     MTG =
  germination (MTG) &             [day number (T) x number of seed
  germination %                   germinated (N) + T2N2 +…+ TnNn]
                                       ÷ [total number germinated]


• Species with the lowest               Germination % =
  MTG and highest
                                        [total number of seeds
  germination % were selected
                                        germinated]
  for the first test of leaf
  extract effect on germination         ÷ [total number of seeds
                                        placed into Petri dish]
               Large Initial Problem

Seed borne disease and/or
          fungus!

•   Devise a series of pre-
    treatment experiments:
                                Most effective treatment –
    - to kill the pathogens,        •20 sec soak in 20% Ethanol
    without having a negative       •30 min soak in 20% Sodium hypochlorite
    impact on germination
    performance.                    solution
                                    •Rinsed with double-distilled water
Turfgrass Species- Seed Solutions (‘Spartan
             Grade A’ mix)

• Perennial ryegrass ‘Quebec’ –
  Lolium perenne ‘Quebec’
• Creeping red fescue ‘SR5210’ –
  Festuca rubra ‘SR5210’

Broadleaf Weed – V&J Seeds
• Dandelion – Taraxacum spp.
    Germination Treatments
• Water Control
• Oak - 4, 8, or 12 ppm
• Sugar Maple – 4, 8 or 12
  ppm
• High Sugar Maple – 4, 8, or
  12 ppm
Each treatment was replicated eight times.

Seeds were placed in growth chambers to
   incubate under ideal germination
   conditions
• 25°C (77° F)
• 14 hour day; 10 hour night


Germination was evaluated daily for a period
   of 15 days.

•   Calculate MTG (mean time to
    germination) & germination %
       Mean Time to Germination

No difference between
 control and seeds
 treated with the oak
 or either of the maple
 water soluble
 extracts.

MTG was ~ 7 days for
 controls and all
 treatments.
                    Germination %


ppm     Species     Dandelion   Perennial Rye ‘Quebec’   Creeping Red Fescue SR5210




 0      Control        94                100                        96
 2       Oak           83                100                        98
 2     S Maple        74*                100                        98

 2    H S Maple        85                100                        96



 4       Oak           84                100                        93
 4     S Maple        78*                100                        87

 4    H S Maple       68*                100                        88



 6       Oak           90                100                        100
 6    Sugar Maple     74*                100                        91

 6    H S Maple       49*                100                        92
    Organic Control of Broadleaf Weeds in
                 Turfgrass
What was next?
Expand Pre-emergence experiments

•  Looking for complete dose                                     High Sugar Maple Senesced Leaf Material
   response –
         What happens to                                    95
                                                            90      85




                                      Percent Germination
   germination as the concentration                         85
                                                            80

   increases?                                               75
                                                            70
                                                            65
                                                                                      68


Test Organic Extracts – preliminary                         60
                                                            55                                             49
   results suggest little effect.                           50
                                                            45

• Testing other turfgrass included                                   2                 4                   6


   in ‘Spartan Grade A’ mix & weed
                                                                                     mg / L


   species for impact on
   germination performance.
        Post-emergence Activity
What is the effect on growth
  of newly germinated
  seedlings?

• Dose response
• Over time
• Frequency of application
Dandelion Post-emergence Control
                              99%
                                     83%       91%    86%

                   100%
      % Coverage
                   80%                                      Dandelion
                   60%                                      Quebec
                   40%    77%                        72%
                                    62%
                                              50%
                   20%
                    0%
                          0         4         8      12
                                        ppm


    •Dandelion % coverage was significantly
    reduced by leaf extract when compared to
    the control
    •Coverage of Quebec turfgrass was not
    significantly different from the control.
Field studies this fall and spring to
                test:
• Barrier – inert vs.
  maple leaf mulch

• Impact on
  establishment
Project Cooperators
   Ron Calhoun
 Aaron Hathaway
 Alec Kowalewski
   Muralee Nair
   Trey Rogers
  Tara Valentino
RESEARCH SUPPORT

      Our thanks to:
          MAES
   PROJECT GREEEN
           MTF
 Kellogg Biological Station
      Seed Solutions

								
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