Daily Light Integral Requirements for Twelve Warm-Season Turfgrasses

Size: px

Start display at page:

Download "Daily Light Integral Requirements for Twelve Warm-Season Turfgrasses"

Rosaline Hensley
6 years ago
Views:

1 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 and J. Bryan Unruh Environmental Horticulture Institute of Food and Agricultural Sciences University of Florida West Florida Research and Education Center and Jason Kruse Environmental Horticulture Institute of Food and Agricultural Sciences University of Florida January 16, P a g e

2 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: 2 P a g e

Turfgrass Quality Light and Temperature Winter Light readings were compiled and averaged for each day (24 hour period) during the course of the study.

3 Turfgrass Quality 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 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). 9 8 y = ln(x) R² = y = ln(x) R² = Figure 1. Turfgrass quality compared to DLI in Tifway bermudagrass, 8 WAS. 3 P a g e

4 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 Captiva St. Augustinegrass Celebration common bermudagrass Diamond zoysiagrass (matrella) Floratam St. Augustinegrass Jamur zoysiagrass (japonica) Palisades zoysiagrass (japonica) Pristine zoysiagrass (matrella) Seadwarf seashore paspalum Tifblair centipedegrass TifGrand hybrid bermudagrass Tifway hybrid bermudagrass 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 Captiva St. Augustinegrass Celebration common bermudagrass Diamond zoysiagrass (matrella) Floratam St. Augustinegrass Jamur zoysiagrass (japonica) Palisades zoysiagrass (japonica) Pristine zoysiagrass (matrella) Seadwarf seashore paspalum Tifblair centipedegrass TifGrand hybrid bermudagrass Tifway hybrid bermudagrass 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

5 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. Materials and Methods: 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. 5 P a g e

Figure 3. Instrument location at Huntington Beach, CA. Data collection and analysis DLI will be collected daily using LightScout DLI 100 meters (Spectrum Technologies, Plainfield, IL).

6 Figure 3. Instrument location at Huntington Beach, CA. Data collection and analysis 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. 6 P a g e

Light Quantity (μmol m-2 day-1) Figure 4. Putting cups with acrylic cap. 2500 2000 1500 1000 Non Acrylic Acrylic Poly. (Non Acrylic) Poly.

7 Light Quantity (μmol m-2 day-1) Figure 4. Putting cups with acrylic cap Non Acrylic Acrylic Poly. (Non Acrylic) Poly. (Acrylic) :00 8:24 10:48 13:12 15:36 18:00 Time of Day Figure 5. Light comparison between with acrylic cap and without. 7 P a g e

8 Experiment 3 - Shade Duration on Turf Morphology Materials and Methods: 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. Data collection and analysis 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 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 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 8 P a g e

9 DLI (mol m -2 d -1 ) DLI (mol m -2 d -1 ) 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 Weekly Avg. Sun Weekly Avg. Shade Week Figure 6. Daily light integral (DLI) by week at Citra in Weekly Avg. Sun Weekly Avg. Shade Week Figure 7. Daily light integral (DLI) by week at Jay in 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). 9 P a g e

10 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. 10 P a g e

11 Table 4. Tifway turfgrass quality at Citra in 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 Turfgrass Quality (1-9) 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 Turfgrass Quality (1-9) 0 WAIS 1 WAIS 2 WAIS 3 WAIS 4 WAIS 5 WAIS 6 WAIS 7 WAIS 8 WAIS 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 11 P a g e

12 Table 7. Celebration turfgrass quality at Jay in Turfgrass Quality (1-9) 1 WAIS 2 WAIS 3 WAIS 4 WAIS 5 WAIS 6 WAIS 7 WAIS 8 WAIS 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 Turfgrass Quality (1-9) 1 WAIS 2 WAIS 3 WAIS 4 WAIS 5 WAIS 6 WAIS 7 WAIS 8 WAIS 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 Turfgrass Quality (1-9) 0 WAIS 1 WAIS 2 WAIS 3 WAIS 4 WAIS 5 WAIS 6 WAIS 7 WAIS 8 WAIS 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 12 P a g e

13 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). 13 P a g e

14 Table 10. Biomass for Tifway at Citra in Biomass (g d -1 ) 1 WAIS 2 WAIS 3 WAIS 4 WAIS 5 WAIS 6 WAIS 7 WAIS 8 WAIS 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 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 a 2.76 a 2.06 a 4.21 a 5.16 a 50 % Shade - Bi-Weekly 1.53 a 1.44 a 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 Biomass (g d -1 ) 1 WAIS 2 WAIS 3 WAIS 4 WAIS 5 WAIS 6 WAIS 7 WAIS 8 WAIS 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 14 P a g e

15 Table 13. Biomass for Celebration at Jay in Biomass (g d -1 ) 1 WAIS 2 WAIS 3 WAIS* 4 WAIS 5 WAIS 6 WAIS 7 WAIS 8 WAIS Untreated 0.05 a 0.04 b b 0.22 b 0.14 a 0.28 ab 0.56 a 50 % Shade - Weekly 0.18 a 0.51 ab b 0.59 ab 0.19 a 0.44 a 0.89 a 50 % Shade - Bi-Weekly 0.11 a 0.12 ab b 0.31 b 0.33 a 0.28 ab 0.66 a 50 % Shade - Monthly 0.23 a 1.13 a a 0.72 a 0.16 a 0.12 b 0.44 a * denotes incomplete data set Table 14. Biomass for Seadwarf at Citra in Biomass (g d -1 ) 1 WAIS 2 WAIS 3 WAIS 4 WAIS 5 WAIS 6 WAIS 7 WAIS 8 WAIS 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 Biomass (g d -1 ) 1 WAIS 2 WAIS 3 WAIS* 4 WAIS 5 WAIS 6 WAIS 7 WAIS 8 WAIS Untreated 0.39 a 0.57 b b 0.69 b 0.39 b 0.48 ab 0.75 a 50 % Shade - Weekly 0.51 a 0.84 b b 0.84 ab 0.25 b 0.42 ab 0.74 a 50 % Shade - Bi-Weekly 0.86 a 0.91 b ab 1.34 a 1.12 a 0.61 a 0.68 a 50 % Shade - Monthly 0.90 a 2.55 a a 1.09 ab 0.39 b 0.17 b 0.43 a * denotes incomplete data set 15 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).

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.

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.

16 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 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 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 P a g e

8 weeks, respectively, at Citra in 2012. Figure 10.

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

shade 1 month increments (on, off) 70% shade 1 week

weeks increments (on, off, on, off) 70% shade 1

17 Figure 9. Celebration 50% shade month treatment at 0, 4, and 8 weeks, respectively, at Citra in Figure 10. Tifway 50% shade month treatment at 0, 4, and 8 weeks, respectively, at Citra in Treatments 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) 70% shade 1 week increments (on and off every week) 70% shade 2 weeks increments (on, off, on, off) 70% shade 1 month increments (on, off) Table 16. Treatments for shade duration on turf morphology field experiment. 17 P a g e

18 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: P a g e

Winter Overseeding Trials on Athletic Field - Fairway Height Bermudagrass 2012/2013

Winter Overseeding Trials on Athletic Field - Fairway Height Bermudagrass 2012/2013 Grady Miller and Scott Brinton North Carolina State University Best for Dark Color: Natural Knit ASP0112 ASP6003 ASP1001GL