Micah Woods
September 27, 2015
1.6k

# If turfgrass growth were a recipe, these are the ingredients

In this presentation, I discuss the four environmental factors, or ingredients, that have a controlling effect on turfgrass growth. These are light, specifically the photosynthetically active radiation; the temperature; the plant water status; and the leaf nitrogen content. All of these factors influence the growth rate of the grass, and I discuss how greenkeepers can understand, measure, and monitor these factors.

## Micah Woods

September 27, 2015

## Transcript

1. ### If turfgrass growth were a recipe, these are the ingredients

Micah Woods Asian Turfgrass Center www.asianturfgrass.com 28 September 2015
2. ### The 4 “ingredients” of growth One can either control or

measure all of the “ingredients.”
3. ### The 4 “ingredients” of growth One can either control or

measure all of the “ingredients.” ▶ Temperature
4. ### The 4 “ingredients” of growth One can either control or

measure all of the “ingredients.” ▶ Temperature ▶ Water
5. ### The 4 “ingredients” of growth One can either control or

measure all of the “ingredients.” ▶ Temperature ▶ Water ▶ Light
6. ### The 4 “ingredients” of growth One can either control or

measure all of the “ingredients.” ▶ Temperature ▶ Water ▶ Light ▶ Nitrogen

12. ### -10 0 10 20 30 Jan 2014 Apr 2014 Jul

2014 Oct 2014 Jan 2015 Temperature (°C) Sapporo 2014
13. ### The turfgrass growth potential (GP) Cool-season grass is expected to

have its best growth when mean temperature is from 16 to 24℃. GP = e−0.5(t−to var )2 GP = growth potential, on a scale of 0 to 1 e = 2.71828, a mathematical constant t = average temperature for a location, in ℃ to = optimum temperature, 20 for C3 grass, 31 for C4 grass var = adjusts the change in GP as temperature moves away from to ; I suggest 5.5 for C3 and 7 for C4
14. ### 0.00 0.25 0.50 0.75 1.00 Jan 2014 Apr 2014 Jul

2014 Oct 2014 Jan 2015 Growth potential (GP) Sapporo 2014
15. ### 0 20 40 60 Jan 2014 Apr 2014 Jul 2014

Oct 2014 Jan 2015 Daily precipitation (mm) Sapporo 2014
16. ### 0 250 500 750 1000 1250 Jan 2014 Apr 2014

Jul 2014 Oct 2014 Jan 2015 Cumulative precipitation (mm) Sapporo 2014
17. ### 0 2 4 6 Jan 2014 Apr 2014 Jul 2014

Oct 2014 Jan 2015 Daily ETo (mm) Sapporo 2014
18. ### 0 200 400 600 800 Jan 2014 Apr 2014 Jul

2014 Oct 2014 Jan 2015 Cumulative sum of ETo (mm) Sapporo 2014
19. ### -60 -40 -20 0 5 Jan 2014 Apr 2014 Jul

2014 Oct 2014 Jan 2015 Daily ETo - precipitation (mm) Sapporo 2014
20. ### -400 -300 -200 -100 0 Jan 2014 Apr 2014 Jul

2014 Oct 2014 Jan 2015 Cumulative sum of ETo - precipitation (mm) Sapporo 2014
21. ### PAR, PPFD, DLI What do these mean? ▶ PAR is

photsynthetically active radiation. It is the light with wavelengths from 400 to 700 nm. ▶ PAR is measured instantaneously as a flux of photons within those wavelengths on a surface of 1 m2. ▶ Instantaneous PAR is the photosynthetic photon flux density, (PPFD). ▶ Adding together all the PAR from each second of the day gives the daily light integral, DLI.
22. ### 0 20 40 60 Jan 2014 Apr 2014 Jul 2014

Oct 2014 Jan 2015 Max possible DLI Sapporo 2014
23. ### 0 20 40 60 Jan 2014 Apr 2014 Jul 2014

Oct 2014 Jan 2015 Actual DLI Sapporo 2014
24. ### 0.25 0.50 0.75 1.00 Jan 2014 Apr 2014 Jul 2014

Oct 2014 Jan 2015 DLI index Sapporo 2014
25. ### 0.00 0.25 0.50 0.75 1.00 Jan 2014 Apr 2014 Jul

2014 Oct 2014 Jan 2015 shade index Sapporo 2014
26. ### Nitrogen ▶ Nitrogen is the one factor influencing growth that

greenkeepers can control. ▶ The nitrogen supply to the grass will be proportional to a combination of temperature, plant water status and light, adjusted for the site-specific requirement for growth.