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Using the MLSN method for turfgrass
nutrient requirements
Micah Woods
12 December 2018
Chief Scientist
Asian Turfgrass Center
www.asianturfgrass.com
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Nutrient deficiencies are avoidable
disasters.
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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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MLSN1 is a method for soil test interpretation.
1An initialism for minimum levels for sustainable nutrition.
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Using MLSN
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Let’s make sure we have enough beer
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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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a, site-specific estimate of plant
use
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Growth = nutrient use
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3 ways to get a number for growth
1. Estimate from clippings.
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3 ways to get a number for growth
1. Estimate from clippings.
2. Estimate from N applied.
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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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b, the quantity of element kept in the soil
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c, the soil test result
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MLSN newsletter:
www.subscribepage.com/mlsn
ATC newsletter:
www.subscribepage.com/atcupdate
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Why an approach like MLSN is
necessary
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Objective of turfgrass fertiliser applications
Ensure the turf is supplied with just what it requires, while at
the same time avoiding (or minimizing) overapplication.
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47 years ago …
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“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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40 years ago …
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“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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“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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Seventeen years ago …
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“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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Five years ago …
Surely these issues have been resolved?
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“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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“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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Festuca, Iceland
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Zoysia, Italy
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Agrostis, Cynodon, and Festuca, Portugal
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Poa annua, France
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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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Poa pratensis, Japan
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Paspalum vaginatum, Thailand
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Axonopus compressus, Indonesia
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Digitaria didactyla, Sri Lanka
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Two recent solutions
1. Fertiliser recommendations without soil test data.
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Two recent solutions
1. Fertiliser recommendations without soil test data.
2. Fertiliser recommendations with soil test data.
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Fertiliser recommendations
without soil test data
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In this case, it makes sense to apply—at least initially—all that
the plant can use.
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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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“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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“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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Fertiliser recommendations with
soil test data
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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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How we developed MLSN
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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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3 common questions
1. MLSN is a target level, or minimum level?
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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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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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For more, please see
www.asianturfgrass.com.