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
2. Sunrise at ATC Research Facility, January 2008
3. ATC Research Facility, 9 March 2008
4. ATC Research Facility, 9 March 2008
5. pH 6.3, K 39 ppm
6. Today’s topics 1. Objective: ideal nutrient recommendations
7. Today’s topics 1. Objective: ideal nutrient recommendations 2. Development: where do mlsn values come from?
8. Today’s topics 1. Objective: ideal nutrient recommendations 2. Development: where do mlsn values come from? 3. Procedure: nutrient recommendations with mlsn
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
11. Objective: ideal nutrient recommendations
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.
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.
14. The minimum and the maximum amount to apply are the same. I call this the right amount, or just what the grass requires.
15. Development: where do mlsn values come from?
16. Large set of soil data from good-performing turf
17. Collaboration: ATC x PACE Turf
29. Procedure: nutrient recommendations with mlsn
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
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
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
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
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
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
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
37. Results: what happens when using this method
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
39. Keya GC in Fukuoka, Japan
40. Keya GC in 2012
41. Keya GC in 2013
42. Keya GC in 2014
43. Keya GC in 2015
44. Keya GC in 2016
45. Keya GC in 2017
46. Keya GC in 2018
47. Keya GC in 2019
48. Total applied in 7 years Potassium 7.4 lb/1000 ft2 (37 g/m2) Phosphorus 0.2 lb/1000 ft2 (1 g/m2)
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
51. www.asianturfgrass.com