daily light integral requirements for twelve warm-season … · 2015. 2. 10. · 3 | p a g e light...

1 | P a g e

Daily Light Integral Requirements for Twelve Warm-Season Turfgrasses

First Year Update

Submitted to

Florida Golf Course Superintendents Association

By

Brian Glenn

Environmental Horticulture

Institute of Food and Agricultural Sciences

University of Florida

[email protected]

and

J. Bryan Unruh



University of Florida – West Florida Research and Education Center

[email protected]

and

Jason Kruse



University of Florida

[email protected]

January 16, 2014

mailto:[email protected]



2 | P a g e

The objectives of the research are to:

1. Quantify the DLI requirement for common warm-season turfgrasses;

2. Establish if these cultivars are exhibiting shade tolerant characteristics under low light;

3. Determine the rate of etiolation and changes in morphology under varying levels and

duration of shade; and

4. Determine the variation in DLI requirements as influence by seasonal temperature and

light changes.

Experiment 1 - Daily Light Integral Screen

Materials and Methods:

Greenhouse trials were conducted to evaluate DLI requirements for 12 warm season turfgrasses

and the effects of reduced light on leaf morphology. Four levels of irradiance (0, 30, 60, and

90% of full sun) were implemented using neutral shade cloth. The cloth was suspended over the

benches using PVC shade structures, allowing for air movement and no direct light due to sun

angle. Light quality measurements using a PS-100 spectroradiometer (Apogee Instruments,

Logan, UT) were taken to assure no differences in red/far red between treatments. Light quantity

was measured using silicon pyranometers (Spectrum Technologies, Plainfield, IL) set to measure

PAR wavelengths. Measurements were record every minute with WatchDog 1650 Micro Station

dataloggers (Spectrum Technologies, Plainfield, IL).

The experiment was conducted multiple times throughout the year to account for seasonal

fluctuations in temperatures. Temperature data were recorded every minute and averaged for the

length of the experiment. The DLI requirements will be compared within cultivars to determine

if light requirements for acceptable turf quality vary based on temperature, and to what degree if

requirements differ.

Experimental Design

The experiment was a split-plot with three replications. Grass species/cultivars were arranged

randomly within each irradiance block. Turfgrass species and cultivars evaluated were ‘Tifway’

and ‘TifGrand’ bermudagrass (Cynodon dactylon X C. transvaalensi), ‘Celebration’

bermudagrass (Cynodon dactylon), ‘Palisades’ and ‘JaMur’ zoysiagrass (Zoysia japonica),

‘PristineFlora’ and ‘Diamond’ zoysiagrass (Zoysia matrella), ‘Floratam’ and ‘Captiva’ St.

Augustinegrass (Stenotaphrum secondatum), ‘TifBlair’ centipedegrass (Eremochloa

ophiuroides), ‘Argentine’ bahiagrass (Paspalum notatum), and ‘SeaDwarf’ seashore paspalum

(Paspalum vaginatum).

Data collection and analysis

Turf quality was evaluated weekly on a visual scale based on color, uniformity, and density. A

scale of 1-9 was used; 1 = dead turf, 9 = ideal green, density, and uniformity for the species, with

6 = minimum acceptable level. All data was subjected to statistical analysis.

Results:

3 | P a g e

Light and Temperature – Winter

Light readings were compiled and averaged for each day (24 hour period) during the course of

the study. The average Daily Light Integral (DLI) during the winter was 16.8±4.1 and 16.5±2.6

mol m-2

d-1

in full sun for 2012 and 2013, respectively. The average temperature during the

duration of the trial was 23.1±2.0 and 21.8±1.1 ⁰C for 2012 and 2013, respectively. In 2012, the

average maximum temperature was 32.2 ±4.4 ⁰C and the average minimum temperature was

17.5±1.7 ⁰C. The average maximum temperature was 28.1±1.0 ⁰C and the average minimum

temperature was 17.5±1.1 ⁰C in 2013.

Light and Temperature – Summer

The average DLI during the summer was 27.4±10.3 and 24.5±5.3 mol m-2

d-1

in full sun for 2012

and 2013, respectively. The maximum DLI recorded in full sun for the trial period was 48.0 and

40.5 mol m-2

d-1

, and the minimum was 5.2 and 8.4 mol m-2

d-1

for 2012 and 2013, respectively.

The average temperature during duration of the trials was 31.9±0.5 ⁰C. The average maximum

temperature was 36.6±1.3 ⁰C and the average minimum temperature was 26.8±0.4 ⁰C.

DLI Comparison

Light requirements for DLI needed to maintained minimum acceptable turfgrass quality (TQ)

was calculate for each turfgrass in both years using regression analysis for turfgrass quality

ratings taken at eight weeks after shading (WAS) (Figure 1). In the winter trials Tifway,

TifGrand, and Tifblair had the highest DLI requirement for both years (Table 1). JaMur,

Pristine, and Diamond had the lowest DLI requirements for both years (Table 1). The highest

average DLI requirement was 10.7 mol m-2

s-1

(Tifway), and the lowest was 6.7 mol m-2

s-1

(JaMur) (Table 1). In the summer trial, Tifway, TifGrand, and Celebration had the highest DLI

requirements in both years (Table 2). JaMur, Captiva and Pristine had the lowest DLI

requirements in both years (Table 2). The highest average DLI requirement was 22.4 mol m-2

s-1

(Tifway), and the lowest was 10 mol m-2

s-1

(JaMur) (Table 2).

Figure 1. Turfgrass quality compared to DLI in Tifway bermudagrass, 8 WAS.

y = 2.3568ln(x) - 1.1234

R² = 0.9202

y = 2.5384ln(x) - 0.1997

R² = 0.9555

1

2

3

4

5

6

7

8

9

0 5 10 15 20 25 30

Tu

rfgra

ss Q

ual

ity

4 | P a g e

Table 1. DLI requirements for warm season turfgrasses in greenhouse experiment under winter

temperatures.

DLI Requirement (mol m-2

s-1

)

Turfgrass Cultivar Winter 2012 Winter 2013 Winter Average

Argentine bahiagrass 6.3 8.7 7.5

Captiva St. Augustinegrass 8.6 7.1 7.8

Celebration common bermudagrass 8.5 9.0 8.8

Diamond zoysiagrass (matrella) 7.4 7.6 7.5

Floratam St. Augustinegrass 9.6 7.6 8.6

Jamur zoysiagrass (japonica) 7.4 6.1 6.7

Palisades zoysiagrass (japonica) 8.2 8.1 8.2

Pristine zoysiagrass (matrella) 7.6 7.0 7.3

Seadwarf seashore paspalum 8.0 7.9 8.0

Tifblair centipedegrass 8.6 10.3 9.4

TifGrand hybrid bermudagrass 9.7 10.0 9.8

Tifway hybrid bermudagrass 11.5 9.8 10.7

Table 2. DLI requirements for warm season turfgrasses in greenhouse experiment under summer

temperatures.

DLI Requirement (mol m-2

s-1

)

Turfgrass Cultivar Summer 2012 Summer 2013 Summer Average

Argentine bahiagrass 16.0 14.7 15.3

Captiva St. Augustinegrass 11.2 10.6 10.9

Celebration common bermudagrass 18.1 20.9 19.5

Diamond zoysiagrass (matrella) 11.7 10.9 11.3

Floratam St. Augustinegrass 11.9 11.6 11.8

Jamur zoysiagrass (japonica) 10.5 9.6 10.0

Palisades zoysiagrass (japonica) 12.0 10.6 11.3

Pristine zoysiagrass (matrella) 11.3 10.5 10.9

Seadwarf seashore paspalum 13.5 12.9 13.2

Tifblair centipedegrass 13.3 13.7 13.5

TifGrand hybrid bermudagrass 18.7 18.6 18.6

Tifway hybrid bermudagrass 23.3 21.4 22.4

5 | P a g e

Experiment 2 – Assessment of Daily Light Integral Monitoring Equipment on Golf Course

Putting Greens

A field trial will be conducted starting in 2013 to determine the functionality of commercially

available DLI monitoring equipment available to turfgrass managers. Current DLI instruments

will be compared to instruments used in research to monitor DLI to compare accuracy and

practicality.


Experimental Design

The experiment will be a randomized complete block design with four replications. The

experiment will be performed on the UF golf team practice green at the Mark Bostick Golf

Course in Gainesville, FL and the #16 green at SeaCliff Country Club in Huntington Beach, CA.

Plots will be located on opposite sides of the putting green beside the collar (Figures 2 and 3).

Figure 2. Instrument location at Gainesville, FL.

6 | P a g e

Figure 3. Instrument location at Huntington Beach, CA.


DLI will be collected daily using LightScout DLI 100 meters (Spectrum Technologies,

Plainfield, IL). These data will be compared with data obtained from a datalogger fitted with a

quantum sensor programmed to collect readings every minute. All equipment will be placed

within modified plastic putting cups fitted with 8.5 mm thick acrylic caps (Figure 4). Caps

created an average of 19.4% reduction in light when compared to full sun (Figure 5). Cups were

placed beside one another on an east-west orientation, approximately 10 cm apart. All sensors

were oriented north to maximize light interception.

7 | P a g e

Figure 4. Putting cups with acrylic cap.

Figure 5. Light comparison between with acrylic cap and without.

0

500

1000

1500

2000

2500

6:00 8:24 10:48 13:12 15:36 18:00

Lig

ht

Qu

anti

ty (

μm

ol

m-2

day

-1)

Time of Day

Non Acrylic

Acrylic

Poly. (Non Acrylic)

Poly. (Acrylic)

8 | P a g e

Experiment 3 - Shade Duration on Turf Morphology


Field trials were conducted to determine the amount of time and the degree in which

morphological changes occur in certain turfgrasses. Recovery time and degree following shade

treatments were also implemented.

Experimental design

The experiment was a randomized complete block design with four replications. Plots were 1.5

m by 1.5 m. The duration of the trial was two months during the spring where minimal amounts

of cloud cover can be attained. Four different levels of irradiance were implemented using

neutral shade cloth (Table 3).

Table 3. Treatments for shade duration on turf morphology field

experiment.

Treatment Duration

Untreated (no shade) 2 months

50% shade 1 week increments (on and off every week)

50% shade 2 weeks increments (on, off, on, off)

50% shade 1 month increments (on, off)

The shade cloth was suspended over the turfgrass plots using PVC shade structures, allowing for

air movement and no supplemental light due to sun angle. Structures were removed for mowing

and data collection.


Plots were evaluated weekly. Turf color, quality, and density was rated on a visual scale of 1-9;

1 = dead turf, 9 = ideal green, density, and uniformity for the species, with 6 = minimum

acceptable level. Measurements were record every minute with WatchDog 1650 Micro Station

dataloggers (Spectrum Technologies, Plainfield, IL). Clippings were collected weekly and

weighed to determine shoot biomass. All data were subjected to statistical analysis.

Light Quantity

Light readings were compiled and averaged for each 24 h period during the course of the study.

The duration of the study in Citra, FL was from May 15 through July 9 in 2012. The average

DLI for the trial was 48.4±15.2 mol m-2

d-1

in full sun and 26.2±8.2 mol m-2

d-1

for those

treatments under shade (Figure 6). The maximum DLI recorded in full sun for the trial period

was 67.2 mol m-2

d-1

, and the minimum was 15.9 mol m-2

d-1

. The maximum and minimum for

DLI under shade was 36.1 and 8.1 mol m-2

d-1

, respectively. The experiment in Jay, FL ran from

May 11 through July 6 in 2012. The average DLI during the duration of the trial was 54.0±15.4

mol m-2

d-1

in full sun, and 26.6±7.6 mol m-2

d-1

for those treatments under shade (Figure 7).

The maximum DLI recorded under full sun for the trial period was 71.3 mol m-2

d-1

, and the

minimum was 16.5 mol m-2

d-1

. The maximum DLI under shade was 35.1 mol m-2

d-1

, and the

9 | P a g e

minimum observed was 8.1 mol m-2

d-1

. The average DLI for sun and shade treatments by week

for Citra and Jay are plotted in Figures 2 and 3, respectively.

Figure 6. Daily light integral (DLI) by week at Citra in 2012.

Figure 7. Daily light integral (DLI) by week at Jay in 2012.

Turfgrass Quality

Turfgrass quality (TQ) was compared using Fisher’s LSD by location and turfgrass species. For

Tifway, only the monthly shading (MS) treatment showed significant differences from the

untreated plots (Tables 4 and 5). In Citra, only MS caused unacceptable TQ for more than one

week (Table 4). After the treatment was removed at 4 weeks after initial shading (WAIS), four

weeks were required to reach acceptable TQ. In Jay, only MS at 4 and 6 WAIS resulted in

below acceptable TQ, with only 6 WAIS being significant (Table 5). Celebration had

unacceptable TQ in Citra for three weeks at 4-6 WAIS for MS, and one week in Jay at 8 WAIS.

All other significant treatments for both locations had a higher TQ than untreated plots (Table 6

and 7). Of the treatments, only MS had unacceptable TQ on TifGrand at 8 WAIS (Table 8). TQ

was unacceptable only at 4 WIAS for Seadwarf at the MS (Table 9).

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

0 2 4 6 8

DL

I (m

ol

m-2

d-1

)

Week

Weekly Avg. Sun

Weekly Avg. Shade

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

0 1 2 3 4 5 6 7 8

DL

I (m

ol

m-2

d-1

)

Week

Weekly Avg. Sun

Weekly Avg. Shade

10 | P a g e

The only treatment that had a significant negative effect on TQ for any turfgrass was MS, and

not until at least 4 WAIS. In many treatments, shade treatments improved TQ for at least a

period of time.

11 | P a g e

Table 4. Tifway turfgrass quality at Citra in 2012.

Turfgrass Quality (1-9)

0 WAIS 1 WAIS 2 WAIS 3 WAIS 4 WAIS 5 WAIS 6 WAIS 7 WAIS 8 WAIS

Untreated 6.33 a 6.83 a 6.33 a 6.67 b 6.67 a 6.50 a 6.67 a 5.67 ab 6.33 a

50 % Shade - Weekly 6.33 a 6.83 a 6.50 a 7.00 ab 6.50 a 6.83 a 5.83 a 6.50 a 6.83 a

50 % Shade - Bi-Weekly 6.33 a 6.67 a 6.50 a 7.00 ab 6.50 a 6.67 a 6.17 a 5.83 ab 6.33 a

50 % Shade - Monthly 6.33 a 7.17 a 6.67 a 7.17 a 5.33 b 5.00 b 5.50 a 5.17 b 6.67 a

Table 5. Tifway turfgrass quality at Jay in 2012


1 WAIS 2 WAIS 3 WAIS 4 WAIS 5 WAIS 6 WAIS 7 WAIS 8 WAIS

Untreated 7.83 a 7.00 b 6.30 a 6.50 a 6.70 a 7.00 a 7.00 a 6.17 a

50 % Shade - Weekly 7.67 a 7.50 a 7.30 a 6.83 a 6.70 a 6.30 ab 7.30 a 6.83 a

50 % Shade - Bi-Weekly 7.67 a 7.33 a 7.30 a 7.00 a 6.70 a 6.30 ab 6.70 a 6.83 a

50 % Shade - Monthly 7.67 a 7.33 a 6.70 a 5.83 a 6.00 a 5.30 b 6.70 a 6.17 a

Table 6. Celebration turfgrass quality at Citra in 2012.



Untreated 6.83 a 6.83 a 6.83 b 7.17 a 7.17 a 6.67 a 7.00 a 7.17 a 7.50 a

50 % Shade - Weekly 6.67 a 7.00 a 7.00 b 7.17 a 7.33 a 6.67 a 6.83 a 7.00 a 6.67 a

50 % Shade - Bi-Weekly 6.50 a 7.00 a 7.33 a 7.33 a 7.00 a 7.00 a 6.33 ab 6.33 a 6.33 a

50 % Shade - Monthly 6.67 a 7.00 a 7.33 a 7.00 a 5.50 b 5.33 b 5.67 b 6.83 a 6.83 a

12 | P a g e

Table 7. Celebration turfgrass quality at Jay in 2012.



Untreated 7.00 b 7.00 b 5.30 c 6.17 c 5.70 b 5.30 b 5.70 c 6.50 b

50 % Shade - Weekly 7.00 b 7.33 ab 6.30 ab 7.00 b 7.00 ab 6.00 ab 7.30 a 7.17 a

50 % Shade - Bi-Weekly 7.17 b 7.50 a 5.70 bc 6.67 b 6.30 ab 7.00 a 6.70 ab 7.17 a

50 % Shade - Monthly 7.50 a 7.33 ab 6.70 a 7.50 a 7.70 a 6.70 a 6.00 bc 5.67 c

Table 8. TifGrand turfgrass quality at Jay in 2012



Untreated 7.00 a 6.67 b 5.30 c 6.17 c 6.30 b 6.70 b 7.00 a 6.33 b

50 % Shade - Weekly 7.00 a 7.00 a 6.00 bc 6.67 b 8.00 a 7.00 ab 7.30 a 7.17 a

50 % Shade - Bi-Weekly 7.00 a 7.00 a 6.70 ab 6.50 bc 8.00 a 7.70 a 7.00 a 6.00 bc

50 % Shade - Monthly 7.00 a 7.17 a 7.00 a 7.50 a 7.30 a 6.30 b 6.00 b 5.33 c

Table 9. Seadwarf turfgrass quality at Citra in 2012.



Untreated 7.17 ab 7.50 a 7.33 b 7.17 a 6.67 a 6.83 a 6.67 a 6.83 a 7.30 a

50 % Shade - Weekly 7.33 a 7.33 a 7.33 b 7.50 a 6.67 a 6.67 a 7.17 a 7.00 a 7.00 a

50 % Shade - Bi-Weekly 6.83 b 7.33 a 7.67 ab 6.83 a 6.50 a 6.67 a 6.50 a 6.67 a 7.00 a

50 % Shade - Monthly 7.33 a 7.50 a 8.00 a 7.17 a 5.17 b 6.33 a 6.83 a 7.00 a 7.30 a

13 | P a g e

Biomass

On average, biomass was significantly higher for most treatments between 2-8 WAIS on Tifway

at Citra (Table 10). At Jay, biomass for WS was significantly higher at 5 and 8 WAIS (Table

11). Numerous treatments were significant on Celebration at Citra between 2-8 WAIS both

increasing and decreasing biomass compared to the untreated plots (Table 12). Significant

increases were seen on MS treatments on Celebration at Jay until 6 WAIS (Table 13). MS

increased biomass significantly on Seadwarf at 2 WAIS, and then significantly decreased

biomass from 4-8 WAIS (Table 14). MS also significantly increased biomass before 4 WAIS on

TifGrand, and then reduced biomass after 4 WAIS (Table 15). BWS also significantly increase

biomass production at 5 and 6 WAIS (Table 15).

14 | P a g e

Table 10. Biomass for Tifway at Citra in 2012.

Biomass (g d-1

)


Untreated 0.15 a 0.23 c 0.30 c 0.43 b 0.52 b 0.94 b 0.58 b 0.16 a

50 % Shade - Weekly 0.29 a 0.46 bc 0.67 ab 0.93 a 1.18 a 1.52 ab 1.30 a 0.33 a

50 % Shade - Bi-Weekly 0.37 a 1.08 a 0.48 bc 0.94 a 1.22 a 1.59 a 1.50 a 0.26 a

50 % Shade - Monthly 0.58 a 0.84 ab 0.79 a 1.16 a 1.09 a 1.45 ab 0.97 ab 0.19 a

Table 11. Biomass for Tifway at Jay in 2012.

Biomass (g d-1

)

1 WAIS 2 WAIS 3 WAIS* 4 WAIS 5 WAIS 6 WAIS 7 WAIS 8 WAIS

Untreated 0.81 a 0.71 a

1.28 a 0.94 b 0.86 a 1.57 a 1.51 b

50 % Shade - Weekly 1.78 a 3.54 a 2.18

3.22 a 2.76 a 2.06 a 4.21 a 5.16 a

50 % Shade - Bi-Weekly 1.53 a 1.44 a 3.13

2.02 a 1.91 ab 1.65 a 1.80 a 2.90 ab

50 % Shade - Monthly 2.43 a 3.05 a 4.93 a 1.78 ab 1.27 a 1.47 a 2.16 b

* denotes incomplete data set

Table 12. Biomass for Celebration at Citra in 2012.

Biomass (g d-1

)


Untreated 0.51 a 1.49 c 1.87 bc 2.89 a 1.44 a 1.37 ab 1.57 b 0.25 a

50 % Shade - Weekly 0.84 a 2.17 bc 2.81 a 1.85 b 2.09 a 1.61 a 1.60 b 0.48 a

50 % Shade - Bi-Weekly 0.66 a 2.75 ab 1.67 c 2.42 ab 1.73 a 1.39 ab 2.33 a 0.38 a

50 % Shade - Monthly 0.66 a 3.11 a 2.55 ab 2.29 ab 1.47 a 0.93 b 1.06 b 0.38 a

15 | P a g e

Table 13. Biomass for Celebration at Jay in 2012.

Biomass (g d-1

)


Untreated 0.05 a 0.04 b 0.05 0.19 b 0.22 b 0.14 a 0.28 ab 0.56 a

50 % Shade - Weekly 0.18 a 0.51 ab 0.02 0.45 b 0.59 ab 0.19 a 0.44 a 0.89 a

50 % Shade - Bi-Weekly 0.11 a 0.12 ab 0.03 0.20 b 0.31 b 0.33 a 0.28 ab 0.66 a

50 % Shade - Monthly 0.23 a 1.13 a 0.00 1.52 a 0.72 a 0.16 a 0.12 b 0.44 a


Table 14. Biomass for Seadwarf at Citra in 2012.

Biomass (g d-1

)


Untreated 0.83 A 1.24 b 2.02 bc 2.93 ab 2.25 a 2.40 a 1.89 a 0.81 a

50 % Shade - Weekly 1.43 A 1.83 b 3.01 a 3.07 a 2.15 a 2.10 ab 1.87 a 0.84 a

50 % Shade - Bi-Weekly 1.06 A 2.10 ab 1.76 c 2.32 bc 1.86 a 1.73 b 2.13 a 0.56 b

50 % Shade - Monthly 1.85 A 2.86 a 2.60 ab 2.17 c 1.23 b 1.25 c 1.04 b 0.35 b

Table 15. Biomass for TifGrand at Jay in 2012.

Biomass (g d-1

)


Untreated 0.39 a 0.57 b 0.16 1.34 b 0.69 b 0.39 b 0.48 ab 0.75 a

50 % Shade - Weekly 0.51 a 0.84 b 0.13 1.21 b 0.84 ab 0.25 b 0.42 ab 0.74 a

50 % Shade - Bi-Weekly 0.86 a 0.91 b 0.48 1.38 ab 1.34 a 1.12 a 0.61 a 0.68 a

50 % Shade - Monthly 0.90 a 2.55 a 0.52 2.69 a 1.09 ab 0.39 b 0.17 b 0.43 a


16 | P a g e

Discussion

Overall, only MS had a consistent impact on the parameters measured. When a plot was

negatively affected, these usually occurred around 4 WAIS or beyond (Figures 8-10). By the

end of the trials, most parameters were not significantly different, signifying recovery from any

impact of the treatments. No turfgrass appeared resilient to all impacts from the treatments.

Compared to current research (Experiment 1), unacceptable TQ for bermudagrasses tested begins

around 4 WAIS. The 50% shade cloth was chosen to replicate the average reduction in light by

cloud cover. To further exacerbate the effects of the shade treatment, an increase in shade cloth

cover may be necessary. Although it would not be comparable to most light reduction patterns

due to cloud cover, it could amplify negative effects of shade which could further explain decline

and recovery cycles.

To test a further reduction of light, three new treatments are planned to be added to the

Celebration and Tifway treatments at both Jay and Citra locations in 2013. These will use 70%

shade cloth in addition to the 50% shade cloth treatments, using the same durations (Table 16).

A dwarf bermudagrass, JonesDwarf, is planned to be added to the experiment in 2013. TifEagle

was reported to require 32.6 mol m-2

d-1

to maintain acceptable TQ (Bunnell et al., 2005a). Since

the average DLI under shade treatments for both locations was ~26 mol m-2

d-1

, greater

difference between treatments could be expected.

Figure 8. Seadwarf 50% shade – month treatment at 0, 4, and 8 weeks, respectively, at Citra in

2012.

17 | P a g e

Figure 9. Celebration 50% shade – month treatment at 0, 4, and 8 weeks, respectively, at Citra in

2012.

Figure 10. Tifway 50% shade – month treatment at 0, 4, and 8 weeks, respectively, at Citra in

2012.

Treatments Duration

Untreated (no shade) 2 months







Table 16. Treatments for shade duration on turf morphology field experiment.

18 | P a g e

Literature Cited

Bunnell, B.T., L.B. McCarty, J.E. Faust, W.C. Bridges, Jr., and N.C. Rajapakse. 2005a.

Quantifying a daily light integral requirement of a ‘TifEagle’ bermudagrass golf green.

Crop Sci. 45:569–574.

daily light integral requirements for twelve warm-season … · 2015. 2. 10. · 3 | p a g e light...

Documents