MLSN & Turfgrass Nutrition

Slide 1

Slide 1 text

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

Slide 2

Slide 2 text

Three key points today 1. Results when using MLSN

Slide 3

Slide 3 text

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

Slide 4

Slide 4 text

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

Slide 5

Slide 5 text

Results when using MLSN

Slide 6

Slide 6 text

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

Slide 7

Slide 7 text

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

Slide 8

Slide 8 text

Nutrient deﬁciencies are avoidable disasters.

Slide 9

Slide 9 text

decreasing levels of soil K

Slide 10

Slide 10 text

ATC 南店

Slide 11

Slide 11 text

ATC 南店

Slide 12

Slide 12 text

ATC 南店

Slide 13

Slide 13 text

ATC 南店

Slide 14

Slide 14 text

ATC 南店

Slide 15

Slide 15 text

ATC 南店

Slide 16

Slide 16 text

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

Slide 17

Slide 17 text

No content

Slide 18

Slide 18 text

No content

Slide 19

Slide 19 text

Keya GC, Fukuoka

Slide 20

Slide 20 text

Keya GC, Fukuoka

Slide 21

Slide 21 text

Keya GC, Fukuoka

Slide 22

Slide 22 text

No content

Slide 23

Slide 23 text

No content

Slide 24

Slide 24 text

Keya GC, Fukuoka

Slide 25

Slide 25 text

Keya GC, Fukuoka

Slide 26

Slide 26 text

We developed MLSN because …

Slide 27

Slide 27 text

48 years ago …

Slide 28

Slide 28 text

“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

Slide 29

Slide 29 text

41 years ago …

Slide 30

Slide 30 text

“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.

Slide 31

Slide 31 text

“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

Slide 32

Slide 32 text

Eighteen years ago …

Slide 33

Slide 33 text

“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.

Slide 34

Slide 34 text

Six years ago … Surely these issues have been resolved?

Slide 35

Slide 35 text

“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.

Slide 36

Slide 36 text

“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

Slide 37

Slide 37 text

The conventional way – low, medium, & high classiﬁcation

Slide 38

Slide 38 text

The conventional way GCSAA GCM Magazine, January 2004

Slide 39

Slide 39 text

List of ranges • low • medium • high

Slide 40

Slide 40 text

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

Slide 41

Slide 41 text

“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.”

Slide 42

Slide 42 text

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

Slide 43

Slide 43 text

“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)

Slide 44

Slide 44 text

“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)

Slide 45

Slide 45 text

The MLSN guidelines address these problems

Slide 46

Slide 46 text

Festuca, Iceland

Slide 47

Slide 47 text

Zoysia, Italy

Slide 48

Slide 48 text

Agrostis, Cynodon, and Festuca, Portugal

Slide 49

Slide 49 text

Poa annua, France

Slide 50

Slide 50 text

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

Slide 51

Slide 51 text

Poa pratensis, Japan

Slide 52

Slide 52 text

Paspalum vaginatum, Thailand

Slide 53

Slide 53 text

Axonopus compressus, Indonesia

Slide 54

Slide 54 text

Digitaria didactyla, Sri Lanka

Slide 55

Slide 55 text

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

Slide 56

Slide 56 text

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

Slide 57

Slide 57 text

Fertiliser recommendations without soil test data

Slide 58

Slide 58 text

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

Slide 59

Slide 59 text

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

Slide 60

Slide 60 text

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

Slide 61

Slide 61 text

“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

Slide 62

Slide 62 text

Fertiliser recommendations with soil test data

Slide 63

Slide 63 text

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.

Slide 64

Slide 64 text

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

Slide 65

Slide 65 text

No content

Slide 66

Slide 66 text

No content

Slide 67

Slide 67 text

No content

Slide 68

Slide 68 text

No content

Slide 69

Slide 69 text

No content

Slide 70

Slide 70 text

No content

Slide 71

Slide 71 text

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

Slide 72

Slide 72 text

Practical use of MLSN

Slide 73

Slide 73 text

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.

Slide 74

Slide 74 text

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.

Slide 75

Slide 75 text

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

Slide 76

Slide 76 text

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.

Slide 77

Slide 77 text

a, site-speciﬁc estimate of plant use

Slide 78

Slide 78 text

Growth = nutrient use

Slide 79

Slide 79 text

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

Slide 80

Slide 80 text

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

Slide 81

Slide 81 text

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

Slide 82

Slide 82 text

b, amount to ensure remains in the soil

Slide 83

Slide 83 text

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

Slide 84

Slide 84 text

No content

Slide 85

Slide 85 text

No content

Slide 86

Slide 86 text

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

Slide 87

Slide 87 text

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

Slide 88

Slide 88 text

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?