How MLSN Works

The MLSN guidelines are a modern method for interpreting turfgrass soil tests and making fertilizer recommendations. These guidelines were introduced in 2012 by PACE Turf (Larry Stowell and Wendy Gelernter) and ATC (Micah Woods). In this webinar, Micah will explain how the MLSN guidelines were developed from a large dataset of good-performing and professionally-managed turf. He will show the logic behind the MLSN method, with time-series examples from turfgrass sites. These examples will demonstrate how the MLSN guidelines are applied, and why they are so successful in making recommendations that produce high quality turfgrass surfaces.

Transcript

1. How mlsn Works
   Micah Woods
   22 May 2020
   Chief Scientist
   Asian Turfgrass Center
   www.asianturfgrass.com
   

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2. Sunrise at ATC Research Facility, January 2008
   

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3. ATC Research Facility, 9 March 2008
   

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4. ATC Research Facility, 9 March 2008
   

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5. pH 6.3, K 39 ppm
   

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6. Today’s topics
   1. Objective: ideal nutrient recommendations
   

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7. Today’s topics
   1. Objective: ideal nutrient recommendations
   2. Development: where do mlsn values come from?
   

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8. Today’s topics
   1. Objective: ideal nutrient recommendations
   2. Development: where do mlsn values come from?
   3. Procedure: nutrient recommendations with mlsn
   

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9. Today’s topics
   1. Objective: ideal nutrient recommendations
   2. Development: where do mlsn values come from?
   3. Procedure: nutrient recommendations with mlsn
   4. Results: what happens when using this method
   

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11. Objective: ideal nutrient
    recommendations
    

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12. We want to ensure that the grass is supplied with
    all the nutrients it can use. This quantity is the
    minimum amount to supply.
    

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13. However, adding more nutrients than the grass can
    use, or than the soil can hold, is a waste. Adding
    enough to ensure that grass is supplied with all
    the nutrients it can use is also the maximum
    amount to supply.
    

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14. The minimum and the maximum amount to apply
    are the same. I call this the right amount, or just
    what the grass requires.
    

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15. Development: where do mlsn
    values come from?
    

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16. Large set of soil data from good-performing turf
    

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17. Collaboration: ATC x PACE Turf
    

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29. Procedure: nutrient
    recommendations with mlsn
    

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30. Use three numbers
    1. Expected plant use for the recommendation time period
    2. mlsn minimum to keep untouched in the soil
    3. Soil test result right now
    

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31. amount needed
    a + b −
    amount present
    c =
    fertilizer requirement
    Q
    a is a site-specific estimate of plant use
    b is the mlsn guideline
    c is the soil test result
    

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32. 1. Expected plant use for the recommendation time period
    Table 1: Expected bentgrass use of K, P, Ca, Mg, and S for known amounts of N, in
    pounds.
    lb/1000 ft2
    N K P Ca Mg S
    0.1 0.04 0.01 0.01 0.004 0.01
    1 0.4 0.1 0.1 0.04 0.1
    2 0.8 0.2 0.2 0.1 0.2
    5 1.9 0.6 0.6 0.2 0.6
    10 3.9 1.2 1.2 0.4 1.1
    

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33. 1. Expected plant use for the recommendation time period
    Table 2: Expected bentgrass use of K, P, Ca, Mg, and S for known amounts of N, in
    grams.
    g/m2
    N K P Ca Mg S
    1 0.4 0.1 0.1 0.04 0.1
    5 1.9 0.6 0.6 0.2 0.6
    10 3.9 1.2 1.2 0.4 1.1
    20 7.8 2.4 2.3 0.9 2.3
    

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34. 2. mlsn minimum
    Table 3: mlsn minimum values expressed as mg/kg (ppm), lbs/1000 ft2, and g/m2,
    with the conversion made for a standard depth of 4 inches (10 cm) with a bulk
    density of 1.5 Mg/m3.
    Element mg/kg (ppm) lbs/1000 ft2 g/m2
    S 7 0.2 1
    P 21 0.6 3
    K 37 1.1 6
    Mg 47 1.4 7
    Ca 331 9.9 49
    

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35. 3. Soil test result right now
    Table 4: Soil test data expressed as mg/kg (ppm), lbs/1000 ft2, and g/m2, with the
    conversion made for a standard depth of 4 inches (10 cm) with a bulk density of
    1.5 Mg/m3.
    mg/kg (ppm) lbs/1000 ft2 g/m2
    1 0.03 0.15
    10 0.3 1.5
    21 0.6 3
    37 1.1 6
    100 3 14.9
    1,000 30 149
    

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36. Once we have those numbers …
    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, the mlsn minimum
    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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37. Results: what happens when
    using this method
    

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38. What happens?
    1. supply 100% of plant use
    2. keep a reserve amount in the soil that we know can produce good turf
    3. avoid unnecessary applications
    

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39. Keya GC in Fukuoka, Japan
    

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40. Keya GC in 2012
    

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41. Keya GC in 2013
    

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42. Keya GC in 2014
    

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43. Keya GC in 2015
    

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44. Keya GC in 2016
    

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45. Keya GC in 2017
    

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46. Keya GC in 2018
    

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47. Keya GC in 2019
    

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48. Total applied in 7 years
    Potassium 7.4 lb/1000 ft2 (37 g/m2)
    Phosphorus 0.2 lb/1000 ft2 (1 g/m2)
    

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50. What happens?
    1. supply 100% of plant use
    2. keep a reserve amount in the soil that we know can produce good turf
    3. avoid unnecessary applications
    

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51. www.asianturfgrass.com
    

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