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Turf conditions & optimal efficiency

Micah Woods
February 14, 2018

Turf conditions & optimal efficiency

These are the slides for my half day pre-conference seminar at the Western Canada Turfgrass Association conference. Just doing the work -- fertilizing, topdressing, irrigation, mowing, pest control -- doesn't guarantee that one will get the desired turf surfaces. In fact, one will sometimes notice that the areas receiving the most maintenance actually have the worst turf! That's unfortunate. In this presentation, I explain some portions of what I call the "Grammar of Greenkeeping." This is a way to think of the work done to the turf in terms of what the objectives actually are -- producing a good surface and doing so with the least possible amount of work. When this grammar is implemented, one can either improve results with the same amount of work, which gives improved conditions and improved efficiency. Or, one can get the same results with less work, which is improved efficiency.

Micah Woods

February 14, 2018
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  1. Turf conditions & optimal efficiency Micah Woods 14 February 2018

    Chief Scientist Asian Turfgrass Center www.asianturfgrass.com
  2. Table of Contents in the Grammar 1. Defining turfgrass management

    2. Two uncontrollable factors influencing grass growth 3. Managing water in the soil 4. Nitrogen, temperature, and growth rate 5. Temperature-based growth potential 6. Managing soil organic matter 7. Measuring soil water to estimate soil air 8. Four things to increase roots on putting greens 9. Do you know how much salt is in the irrigation water? 10. Managing salt by leaching 11. Measuring clipping yield from putting greens 12. An easy PAR 13. Similar temperatures, but dissimilar sunshine 14. Two ways to avoid nutrient deficiencies
  3. Today’s “Table of Contents” • Defining turfgrass management • Two

    uncontrollable factors influencing grass growth
  4. Today’s “Table of Contents” • Defining turfgrass management • Two

    uncontrollable factors influencing grass growth • Managing water in the soil
  5. Today’s “Table of Contents” • Defining turfgrass management • Two

    uncontrollable factors influencing grass growth • Managing water in the soil • Nitrogen, temperature, and growth rate
  6. Today’s “Table of Contents” • Defining turfgrass management • Two

    uncontrollable factors influencing grass growth • Managing water in the soil • Nitrogen, temperature, and growth rate • Temperature-based growth potential
  7. Today’s “Table of Contents” • Defining turfgrass management • Two

    uncontrollable factors influencing grass growth • Managing water in the soil • Nitrogen, temperature, and growth rate • Temperature-based growth potential • Managing soil organic matter
  8. Today’s “Table of Contents” • Defining turfgrass management • Two

    uncontrollable factors influencing grass growth • Managing water in the soil • Nitrogen, temperature, and growth rate • Temperature-based growth potential • Managing soil organic matter • Measuring clipping yield from putting greens
  9. Today’s “Table of Contents” • Defining turfgrass management • Two

    uncontrollable factors influencing grass growth • Managing water in the soil • Nitrogen, temperature, and growth rate • Temperature-based growth potential • Managing soil organic matter • Measuring clipping yield from putting greens • An easy PAR
  10. Greenkeeping is managing the growth rate of the grass to

    create the desired playing surface for golf.
  11. What affects growth? Growth is a function of photosynthetic light,

    plant water status, temperature, and a nutrient index.1 This can be represented as the environmental productivity index (EPI). 1Each of these factors can be represented by an index that takes a value from 0 to 1. Thus, the EPI will also have a value in the range of 0 to 1. The nutrient index is primarily a function of leaf N content.
  12. What affects growth? Growth is a function of photosynthetic light,

    plant water status, temperature, and a nutrient index.1 This can be represented as the environmental productivity index (EPI). (light)(water)(temperature)(nutrient) = EPI 1Each of these factors can be represented by an index that takes a value from 0 to 1. Thus, the EPI will also have a value in the range of 0 to 1. The nutrient index is primarily a function of leaf N content.
  13. Another simplified EPI   XXX X (light)  XXX

    X (water)(temperature)(nutrient) = EPI
  14. “We determined through field experiments that in our climate [Wisconsin]

    it takes at least [80 g N/m2/year] to maximize clipping production on a [Poa pratensis] lawn and in excess of [19 g N/m2/month] on a bentgrass fairway.” Houlihan and Kussow, 2006
  15. Grasses can grow well when temperatures are close to an

    optimum for growth, and grasses will grow more slowly or not at all as the temperature moves away from the optimum.
  16. Temperature-based growth potential PACE Turf developed the Temperature-based GP to

    express the actual temperature in terms of its proximity to optimum temperatures for shoot growth. GP = e−0.5( t−to var )2 where, GP = growth potential, on a scale of 0 to 1 e = 2.71828, a mathematical constant t = average temperature for a location, in celsius to = optimum temperature, 20 for C3 grass, 31 for C4 grass var = adjusts the change in GP as temperature moves away from to ; I suggest 5.5 for C3 and 7 for C4
  17. Implications and use of GP • mowing frequency • fungicide

    duration • heat-related stress • topdressing requirement • nutrient use
  18. What’s affected by the growth rate? • divot recovery •

    ball mark recovery • some diseases • traffic damage • green speed • mowing requirement • thatch (and everything associated with its management)
  19. Checking variability • day to day • green to green

    • machine to machine • year to year
  20. 3 terms 1. PAR – photosynthetically active radiation 2. PPFD

    – photosynthetic photon flux density, measured per second 3. DLI – daily light integral, sum of PPFD from sunrise to sunset