Solar Radiation is the Driving Force of Sports Turf Management

Karl Danneberger, Ph.D. The Ohio State University

• Driving force for all biological activity • Biological Activity

– 0 to 50 C (32 to 122 F) – Metabolic processes 10 to 40 C (50 to 104 F)

• Little activity – < 0 C (32 F) – > 50 C (122 F)

Temperature

Alteration of Light Quality

SOLAR RADIATION

absorption

transmission

reflection

rich in red light, low in far-red light

low in red light, rich in far-red light

Slide courtesy of Dr. Alfred Turgeon 2002 ©

Canopy Temperature: Clear, Calm Conditions Wind

86 30

50 10

Ts= 70 F ( 21 C)

Tc=____

Ta= 90 F (32 C)

0 mph

Adequate Soil Moisture

105 F (41 C)

Wind

Canopy Temperature: Clear, Windy Conditions

86 30

50 10

Ts= 70 F ( 21 C)

Tc=____

Ta= 90 F (32 C)

>5 mph

Adequate Soil Moisture

90 F (32 C)

Canopy Temperature: Cloudy, Calm Conditions

86 30

50 10

Ts= 70 F ( 21 C)

Tc=____

Ta= 90 F (32 C)

Wind

0 mph

Adequate Soil Moisture

90 F (32 C)

0 500 1000 1500 Light level (µmol m-2s-1)

2 4

6 8

10

12

Light Saturation Point

Light Compensation Point

C4

C3

•require 4 to 5 hours of full sun/ day •(Fry & Huang, 2004).

•Creeping bentgrass can be shaded up to 6 hours per day (31 percent of full sunlight) and still maintain adequate turf quality

•(Bell & Danneberger, 1999).

•Warm season turfgrasses require more hours of sunlight. ‘Tifeagle’ requires at least 8 hours of full sunlight to provide adequate turf quality

•(Burnell, 2005).

How much Light?

Light Absorption by the Leaf

R<FR R>FR

Shade Avoidance Response

Full Sun (FS) 49 mol m-2 d-1

R:FR = 1.4

Neutral Shade (NS) 4.1 mol m-2 d-1 (8% FS) R:FR = 1.25

Deciduous Shade (DS) 3.4 mol m-2 d-1 (7% FS) R:FR = 0.45

05000

10000150002000025000300003500040000

400

430

460

490

520

550

580

610

640

670

700

730

760

790

Wavelength (nm)

D

etec

tor R

espo

nse

FS R:FR= 1.40 49 mol m-2 d-1

NS R:FR= 1.25 3.4 mol m-2 d-1

DS R:FR= 0.45 4.1 mol m-2 d-1

50%

100%

0%

Spectral Distribution of Treatments

Neutral Shade 3.4 mol m-2 d-1

R:FR = 1.25 Full Sun 49 mol m-2 d-1

R:FR = 1.4

Deciduous Shade 4.1 mol m-2 d-1

R:FR = 0.45

Impact of Raising the Height On Leaf Area and Photosynthetic Potential

Full Sunlight

cv. Equinox

Deciduous Shade cv. Equinox

Figure 1. % of coverage of Crenshaw, Ax6548, and Ax6549 grown in full sun, reduced R:FR, reduced PPF, and reduced PPF and R:FR in 2008.

Clipping interval 10 days

Ax6548, Ax6548 and Crenshaw at the day 1 of experiment. Ax6548, Ax6549, and Crenshaw

grown underfull sun, reduced R:FR, reduced PPF, and reduced PPF&R:FR on day 60 of the study.

Full sun R:FR PPF R:FR&PPF

Ax6548

Ax6549

CR

CR

Figure 5. % of coverage of Crenshaw, Ax6548, and Ax6549 grown in full sun, reduced R:FR, reduced PPF, and reduced PPF and R:FR in 2009.

Clipping interval 5 days

Figure 7. Ax6548, Ax6549 and Crenshaw at the day 1 of experiment. Figure 8. Ax6548, Ax6549, and

Crenshaw grown under full sun, reduced R:FR, reduced PPF, and reduced PPF&R:FR on day 60 of the study.

CR Ax6548 Ax6549

Ax6548 Ax6549 CR

FS R:FR rePPF PPF & R:FR

AirFlow Restriction versus Low Light (Koh, et al. 2003)

Parameter Air Flow Restriction

Shade

Turf Density Decline > Decline

Disease (dollar spot, brown patch)

Pressure > Pressure

Root Mass Loss < Loss

Cultivar difference (L93 versus SR1020), L93 more shade tolerant

100 % (FS N rate) 50 % (FS N Rate)