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MLSN & Turfgrass Nutrition

Micah Woods
November 22, 2019

MLSN & Turfgrass Nutrition

Micah Woods

November 22, 2019
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  1. MLSN & Turfgrass Nutrition
    Micah Woods
    November 26–29, 2019
    Chief Scientist
    Asian Turfgrass Center
    www.asianturfgrass.com

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  2. Three key points today
    1. Results when using MLSN

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  3. Three key points today
    1. Results when using MLSN
    2. We developed MLSN because …

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  4. Three key points today
    1. Results when using MLSN
    2. We developed MLSN because …
    3. Practical use of MLSN

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  5. Results when using MLSN

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  6. MLSN1 is a method for soil test interpretation.
    1An initialism for minimum levels for sustainable nutrition.

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  7. MLSN is designed to prevent nutrient deficiencies based on
    an analysis of the nutrients in the soil and the expected grass
    use of nutrients.

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  8. Nutrient deficiencies are avoidable
    disasters.

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  9. decreasing levels of soil K

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  10. ATC 南店

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  11. ATC 南店

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  12. ATC 南店

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  13. ATC 南店

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  14. ATC 南店

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  15. ATC 南店

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  16. Let’s have a look at soil test phosphorus
    (P) and potassium (K) for a 7 year
    sequence. First, the soil P …

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  19. Keya GC, Fukuoka

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  20. Keya GC, Fukuoka

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  21. Keya GC, Fukuoka

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  24. Keya GC, Fukuoka

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  25. Keya GC, Fukuoka

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  26. We developed MLSN because …

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  27. 48 years ago …

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  28. “Fertilizer is the number one management tool. It is
    worth all the attention you can give it.”
    Madison, 19712
    2Madison, J.H. 1971. Principles of turfgrass culture. New York: Van Nostrand Reinhold Co.
    p. 270

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  29. 41 years ago …

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  30. “A study was conducted to determine differences
    among soil testing laboratories … in fertilizer
    recommendations for turfgrass maintenance and
    establishment.”
    Turner & Waddington, 19783
    3Turner, T.R. and D.V. Waddington. 1978. Survery of soil testing programs for turfgrasses.
    Comm. Soil Sci. Plant Anal. 9(1):71-87.

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  31. “Unfortunately, turfgrass recommendations appear to
    be based on research done with other crops, such as
    forages, results from turfgrass fertility studies not
    designed to relate to soil testing, and the best
    judgement of the agronomist making the
    recommendations.”
    Turner & Waddington, 1978

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  32. Eighteen years ago …

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  33. “In some cases, turfgrasses have been placed in a
    ‘high’ P and K requirement category … This decision
    was based on economics, not agronomics. The cost
    of fertilization was not considered of primary
    importance for turf.”
    Carrow et al., 20014
    4Carrow, R.N., Waddington, D.V., and P.E. Rieke. 2001. Turfgrass Soil Fertility and Chemical
    Problems. Wiley. p. 164.

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  34. Six years ago …
    Surely these issues have been resolved?

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  35. “Calibration of … soil P with turfgrass growth and
    subsequent P fertilization recommendations is scant,
    and additional data is needed. Many current
    recommendations for P fertilizer for turfgrasses are
    based on forage- or field-crop calibration data.”
    Frank & Guertal, 20135
    5Frank, K.W. and E.A. Guertal. 2013. Potassium and phosphorus research in turfgrass. In:
    Stier, J.C., B.P. Horgan, and S.A. Bonos, editors, Turfgrass: Biology, Use, and Management,
    Agron. Monogr. 56. ASA, CSSA, SSSA, Madison, WI. p. 493-519.

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  36. “Relationships between extracted soil K, K fertilization
    rates, and turfgrass response needs additional study.
    Such work is especially missing for the sand-based
    systems in which many turfgrasses are managed.”
    Frank & Guertal, 2013

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  37. The conventional way – low,
    medium, & high classification

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  38. The conventional way
    GCSAA GCM Magazine, January 2004

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  39. List of ranges
    • low
    • medium
    • high

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  40. “Low range: a high probability (80-100%)
    that applying the nutrient will elicit a
    growth response.”

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  41. “Medium range: approximately a 50%
    chance of getting a plant growth response
    …; if supplemental fertilizer is not applied,
    growth will probably be limited, especially
    as the season progresses.”

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  42. “High range: little or no crop response is
    expected from applying the particular
    nutrient.”

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  43. “Every time a researcher conducts one of these
    studies, they tend to find that the levels required are
    lower than what we previously thought – meaning
    that ‘low potassium’ you got on your last soil test
    report might be optimum down the road.”
    Doug Soldat in “How reliable is soil testing?” (2013)

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  44. “I recommend you compare your results with PACE
    Turf’s Minimum Levels for Sustainable Nutrition
    [MLSN] guidelines ... the minimum levels published
    by PACE are drastically lower than many traditional
    soil test interpretations, and likely more accurate.”
    Doug Soldat in “How reliable is soil testing?” (2013)

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  45. The MLSN guidelines address these problems

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  46. Festuca, Iceland

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  47. Zoysia, Italy

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  48. Agrostis, Cynodon, and Festuca, Portugal

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  49. Poa annua, France

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  50. Reality: Conventional soil test calibration
    will never be done for even a fraction of
    the turf species, soil, and climate
    combinations.

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  51. Poa pratensis, Japan

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  52. Paspalum vaginatum, Thailand

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  53. Axonopus compressus, Indonesia

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  54. Digitaria didactyla, Sri Lanka

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  55. Two recent solutions
    1. Fertiliser recommendations without soil test data.

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  56. Two recent solutions
    1. Fertiliser recommendations without soil test data.
    2. Fertiliser recommendations with soil test data.

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  57. Fertiliser recommendations
    without soil test data

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  58. In this case, it makes sense to apply—at least initially—all that
    the plant can use.

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  59. This is the STERF “Precision fertilisation” approach.6
    6Ericsson, T., K. Blombäck and A. Kvalbein. 2013. Precision fertilisation—from theory to
    practice. STERF.

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  60. “Precision fertilisation is based on the assumption
    that during vegetative growth …, grass requires
    nutrients in constant relative proportions.”
    Ericsson et al., 2013

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  61. “By matching fertilisation to requirements during the
    season, it is possible to avoid undesirable
    fluctuations in grass growth and playing quality.”
    Ericsson et al. 2013

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  62. Fertiliser recommendations with
    soil test data

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  63. In this case, one wants to ensure the grass is supplied with all
    that it can use. If the soil can supply some—or all—of that
    amount, then the fertiliser recommendation accounts for the
    soil supply.

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  64. Minimum levels for sustainable nutrition (MLSN)
    • Joint project7 of ATC (me) & PACE Turf (Wendy Gelernter
    and Larry Stowell, California)
    • Started with 16,163 soil samples collected from
    good-performing turf
    • Selected a subset of 3,683 with:
    • pH ≥ 5.5 & ≤ 8.5
    • CECsum ≤ 60 mmolc
    kg-1
    7Woods M.S., L.J. Stowell, and W.D. Gelernter. 2016. Minimum soil nutrient guidelines for
    turfgrass developed from Mehlich 3 soil test results. PeerJ Preprints 4:e2144v1
    https://doi.org/10.7287/peerj.preprints.2144v1

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  71. https://asianturfgrass.shinyapps.io/turfsi/

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  72. Practical use of MLSN

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  73. The two possible extremes
    1. Supply nothing and assume the soil can provide all the
    grass requires.
    2. Supply 100% (or more) of the nutrients the grass can use.8
    8This approach makes the implicit assumption that the soil cannot supply the nutrients.

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  74. Two questions
    1. Is this element required as fertilizer?
    2. If it is required, how much should I apply?
    To answer those questions, we need to know how much is
    used by the grass and how much can be supplied by the soil.

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  75. T
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  76. a, b, and c
    • a is a site-specific estimate of plant use.
    • b is the amount we want to ensure remains in the soil
    after the plant use is accounted for. This is a minimum we
    don’t want to drop below. You can think of it as a reserve
    amount in the soil. This is the MLSN guideline level.
    • c is the amount actually present in the soil. This is the
    soil test result.

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  77. a, site-specific estimate of plant
    use

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  78. Growth = nutrient use

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  79. 3 ways to get a number for growth
    1. Estimate from clippings.

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  80. 3 ways to get a number for growth
    1. Estimate from clippings.
    2. Estimate from N applied.

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  81. 3 ways to get a number for growth
    1. Estimate from clippings.
    2. Estimate from N applied.
    3. Estimate from temperature.

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  82. b, amount to ensure remains in
    the soil

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  83. More specifically...
    One can express the quantity of an element required as
    fertilizer as Q.
    a + b − c = Q
    where,
    a is the quantity of the element used by the grass
    b is the quantity of the element kept in the soil
    c is the quantity of the element present in the soil
    Q is the quantity of the element required as fertilizer

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  86. 3 common questions
    1. MLSN is a target level, or minimum level?

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  87. 3 common questions
    1. MLSN is a target level, or minimum level?
    2. Same minimum for every grass, soil, and location?
    Customization?

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  88. 3 common questions
    1. MLSN is a target level, or minimum level?
    2. Same minimum for every grass, soil, and location?
    Customization?
    3. How do I know the nutrients are available?

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  90. www.asianturfgrass.com

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