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Using and understanding the MLSN guidelines for nutrient recommendations

C62291821dac0dd5b7ef3b72a30cd137?s=47 Micah Woods
January 23, 2018

Using and understanding the MLSN guidelines for nutrient recommendations

These guidelines are designed to prevent nutrient deficiencies based on an analysis of the nutrients in the soil and the expected grass use of nutrients. Since their introduction in 2012, the MLSN guidelines have come into use at turfgrass sites around the world. This workshop shares the latest information about the MLSN guidelines, including how to use them, why they have received so much attention, and points to pay careful attention to when implementing them.

C62291821dac0dd5b7ef3b72a30cd137?s=128

Micah Woods

January 23, 2018
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Transcript

  1. Using and understanding the MLSN guidelines for nutrient recommendations Micah

    Woods January 23, 2018 Chief Scientist Asian Turfgrass Center www.asianturfgrass.com
  2. Today’s schedule 09:25 – 11:25: all about MLSN

  3. MLSN1 is a method for soil test interpretation. 1An initialism

    for minimum levels for sustainable nutrition.
  4. MLSN is designed to prevent nutrient deficiencies based on an

    analysis of the nutrients in the soil and the expected grass use of nutrients.
  5. MLSN newsletter: www.subscribepage.com/mlsn ATC newsletter: www.subscribepage.com/atcupdate

  6. The key concepts

  7. Nutrient deficiencies are avoidable disasters.

  8. 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.2 2This approach makes the implicit assumption that the soil cannot supply the nutrients.
  9. “How many more times do I have to say that

    applying nutrients to turfgrass growing on soil already well supplied with the nutrients is a waste of time and money?” Wayne Kussow in “Manipulating Creeping Bentgrass Nutrition” (1995)
  10. 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.
  11. T o a n s w e r t h

    o s e f u n d a me n t a l q u e s t i o n s , w e n e e d t o e s t i ma t e 3 q u a n t i t i e s c r e e p i n g b e n t g r a s s S h a n g h a i , C h i n a
  12. T o a n s w e r t h

    o s e f u n d a me n t a l q u e s t i o n s , w e n e e d t o e s t i ma t e 3 q u a n t i t i e s c r e e p i n g b e n t g r a s s S h a n g h a i , C h i n a
  13. T o a n s w e r t h

    o s e f u n d a me n t a l q u e s t i o n s , w e n e e d t o e s t i ma t e 3 q u a n t i t i e s c r e e p i n g b e n t g r a s s S h a n g h a i , C h i n a
  14. T o a n s w e r t h

    o s e f u n d a me n t a l q u e s t i o n s , w e n e e d t o e s t i ma t e 3 q u a n t i t i e s c r e e p i n g b e n t g r a s s S h a n g h a i , C h i n a
  15. T o a n s w e r t h

    o s e f u n d a me n t a l q u e s t i o n s , w e n e e d t o e s t i ma t e 3 q u a n t i t i e s c r e e p i n g b e n t g r a s s S h a n g h a i , C h i n a
  16. MLSN is a method for soil test interpretation

  17. 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.
  18. a, site-specific estimate of plant use

  19. Growth = nutrient use

  20. Not like this

  21. Law of the minimum? “In terms of Liebig’s Law of

    the Minimum, nitrogen is usually the element in shortest supply, and therefore applying nitrogenous fertilizers has a large impact on plant growth. The reason that nitrogen, of all the elements, is so often limiting to growth is simply that plants require a great deal of it.” Jonathan Silvertown in Demons in Eden: The Paradox of Plant Diversity (2005)
  22. 3 ways to get a number for growth 1. Estimate

    from clippings.
  23. 3 ways to get a number for growth 1. Estimate

    from clippings. 2. Estimate from N applied.
  24. 3 ways to get a number for growth 1. Estimate

    from clippings. 2. Estimate from N applied. 3. Estimate from temperature.
  25. b, amount to ensure remains in the soil

  26. 1. The conventional way – low, medium, & high classification

  27. 1. The conventional way – low, medium, & high classification

    2. Conventional guidelines are broken
  28. 1. The conventional way – low, medium, & high classification

    2. Conventional guidelines are broken 3. The MLSN guidelines address these problems
  29. The conventional way – low, medium, & high classification

  30. The conventional way GCSAA GCM Magazine, January 2004

  31. List of ranges • low • medium • high

  32. “Low range: a high probability (80-100%) that applying the nutrient

    will elicit a growth response.”
  33. “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.”
  34. “High range: little or no crop response is expected from

    applying the particular nutrient.”
  35. Conventional guidelines are broken

  36. “In some cases, turfgrasses have been placed in a ‘high’

    P and K requirement category, while pasture grasses were in a ‘low’ category. This decision was based on economics, not agronomics. The cost of fertilization was not considered of primary importance for turf.” Carrow, Waddington, and Rieke in Turfgrass Soil Fertility and Chemical Problems (2001)
  37. And grass is often grown in sand

  38. “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 in “Survey of soil testing programs for turfgrasses” (1978)
  39. “Numerous turfgrass fertility studies … either did not take into

    account intitial soil fertility levels, or were conducted on only one level of initial fertility.” Turner & Waddington in “Survey of soil testing programs for turfgrasses” (1978)
  40. None
  41. None
  42. None
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  46. None
  47. “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)
  48. The MLSN guidelines address these problems

  49. “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)
  50. The MLSN guidelines address these problems

  51. c, the amount actually in the soil

  52. Using MLSN

  53. Let’s make sure we have enough beer

  54. 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
  55. 3 common questions 1. MLSN is a target level, or

    minimum level?
  56. 3 common questions 1. MLSN is a target level, or

    minimum level? 2. Same minimum for every grass, soil, and location? Customization?
  57. 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?
  58. For more, please see www.asianturfgrass.com or @asianturfgrass on Twitter.