Minimalist turfgrass nutrition

My slides from the 2017 Alberta Property Managers Conference. I explained how the minimum amount of fertilizer to apply, and the maximum amount to apply, are the same, and can be described as the right amount to apply. Then I discussed how to determine the right amount to apply.

Transcript

1. Minimalist turfgrass nutrition Micah Woods November 27, 2017 Chief Scientist Asian Turfgrass Center www.asianturfgrass.com
2. What are we trying to accomplish?
3. Produce a surface Royal Bangkok Sports Club, Thailand
4. Produce a surface Kashima Soccer Stadium, Japan
5. Produce a surface Manila American Cemetery, Philippines
6. Produce a surface Old Course, St. Andrews, Scotland
7. Prevent nutrient deficiency Progressive K deficiency
8. We want to ensure that the grass is supplied with all the nutrients it can use. This quantity is the minimum amount to supply.
9. 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.
10. The minimum and the maximum amount to apply are the same. I call this the right amount, or just what the grass requires.
11. An aside: why minimalist? Let’s compare to the conventional way
12. GCSAA GCM Magazine, January 2004
13. List of ranges • low • medium • high
14. “Low range: a high probability (80-100%) that applying the nutrient will elicit a growth response.”
15. “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.”
16. “High range: little or no crop response is expected from applying the particular nutrient.”
17. “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
18. And grass is often grown in sand
19. “Turfgrass researchers continue to improve the soil testing recommendations, but that type of research is time consuming and expensive. It is also worth noting that 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
20. So, how can we supply the right amount?
21. In the case of no soil testing With no soil test, it makes sense to supply 100% of what the grass can use.
22. The amount the grass grows controls how much it uses Hanoi Golf Club, Vietnam
23. The amount the grass grows controls how much it uses Keya Golf Club, Japan
24. When there is a soil test It makes sense to supply the amount the grass uses that it can’t get from the soil. That is, the grass use minus the soil test.
25. Keya Golf Club, Japan
26. MLSN is an extra amount to keep in reserve
27. 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 (MLSN) c is the quantity of the element present in the soil Q is the quantity of the element required as fertilizer
28. Let’s make sure we have enough apples
29. Let’s make sure we have enough beer
30. For more, please see www.asianturfgrass.com or @asianturfgrass on Twitter.