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© 2008 Plant Management Network. Surface Firmness and Repair Tool Affect Golf Ball Mark Recovery Jared R. Nemitz, Graduate Research Assistant, and Cale A. Bigelow, Associate Professor, Department of Agronomy, Purdue University, 915 W. State Street, West Lafayette, IN 47907; and Adam C. Moeller, USGA Green Section Agronomist, United States Golf Association, Northeast Region, P.O. Box 4717, Easton, PA 18043 Corresponding author: Jared R. Nemitz. jnemitz@purdue.edu Nemitz, J. R., Bigelow, C. A., and Moeller, A. C. 2008. Surface firmness and repair tool affect golf ball mark recovery. Online. Applied Turfgrass Science doi:10.1094/ATS-2008-1121-01-RS. Abstract Golf ball/pitch marks disrupt putting green surface smoothness and uniformity. A commonly used method for repairing ball/pitch marks employs a traditional metal forked (≈ 3 cm) tool (TT) and a knit-and-twist method. This procedure has the potential to disturb roots and slow turf recovery. New tools intended to minimize root disruption have been introduced, however, performance data relative to the TT is limited. This field study evaluated ball/pitch mark recovery as affected by four repair tools [TT, angled traditional tool (ATT), GreenFix Wizard (GFW), and standard length wooden golf tee (WGT)] on two creeping bentgrass (Agrostis stolonifera L. cult. ‘Pennlinks’) areas with contrasting initial surface firmness and rootzone moisture contents. Recovery was quantified using visual scar injury (SI) ratings and scar area measurements. Among repair tools the TT and GFW generally resulted in the highest SI ratings and fastest recovery. The ATT performance was intermediate and the poorest recovery was associated with the WGT, which was similar to the unrepaired mark on most rating and measurement dates. Although repair tools affected recovery, factors such as surface firmness and moisture content were also very important. Larger and significantly deeper ball marks occurred on the softer surface, resulting in longer recovery periods. Introduction Unrepaired golf ball/pitch marks, hereafter referred to as ball marks, can leave localized necrotic scars, raised turf prone to mower scalping, loss of surface smoothness, and the potential for weed (e.g., Poa annua L.) encroachment (1). The traditional repair method suggested by the Golf Course Superintendent’s Association of America (GCSAA), and encouraged by golf professionals, involves inserting a traditional metal tool with equal length tongs (≈ 3 cm) and employing a knit-and-twist method intended to pull healthy turf from the perimeter (3). This method and tool choice has been scrutinized because traditional repair tools may disrupt and severely damage roots, especially if conducted improperly. Several novel repair tools, including those with shorter tongs (1 cm) and utilizing a perimeter-pushing method, have been commercialized. These tools are designed to push healthy turf forward into the ball mark scar areas resulting in less damage than tools designed to lift soil and twist canopy surfaces. Some data indicate that shorter-tong tools are just as effective as traditional repair tools. The data regarding the field performance of these tools, however, is limited (2,6). Other factors such as surface firmness or rootzone moisture status at the time the ball mark is created have not been studied. In theory, softer surfaces could result in larger ball marks and longer recovery times. Therefore, the objective of this study was to evaluate ball mark recovery on two areas with contrasting surface firmness and rootzone moisture contents as affected by various repair tools. Evaluating the Effects of Surface Firmness on Recovery This study was conducted on a nine-year-old stand of creeping bentgrass (Agrostis stolonifera L. ‘Pennlinks’) cultivated on a USGA (8) specification sand-based research putting green located at the W. H. Daniel Turfgrass Research and Diagnostic Center, West Lafayette, IN. The rootzone consisted of an 80:20 (v:v) sand and spaghum peat mixture. There was no distinct thatch or mat layer present (< 1 cm) and organic matter in the upper 25 mm was 2.8%. During the data collection period, the green was mowed at 3.6 mm with a tri-plex mower six times per week, received N at 146 kg/ha/year and irrigation was provided via an overhead irrigation system to supplement rainfall every 1 to 2 days, providing approximately 25.4 mm/week. No sand topdressing or core cultivation occurred during the study period. Prior to initiating the experiment the study area was divided into two distinct areas (approximately 4.6 × 6.1 m) to create a "firm" and a "soft" location. The firm area was conditioned by repeatedly rolling the area with a GreensIron 3000 (Woodbay Technologies, Edmonton, Canada) sidewinder roller (Fig. 1) until an average surface hardness value of 145 gmax was achieved as measured by the Clegg Impact Soil Tester (0.5 kg model, Lafayette Instrument Co., Lafayette, IN). The surface hardness value for the soft area was 100 gmax. The use of the Clegg Impact Soil Tester is a commonly used method of measuring surface hardness (4,5). The soft area was not rolled, but heavily hand-watered the day of study initiation until surface ponding occurred. The water was allowed to briefly soak into the rootzone and the watering process repeated multiple times. Volumetric water content of each area was measured using a portable soil moisture probe equipped with a portable time domain reflectance soil moisture probe (TDR) (POGO Soil Sensor, Stevens Water Monitoring Systems, Beaverton, OR). The average surface moisture contents at the 0 to 5-cm depth were 20 and 28% for the firm and soft areas, respectively.
Ball marks were naturally created on 12 June 2007 by the impact of golf balls struck into each research area from a distance of 100 m using a pitching wedge. Four ball mark repair tools (Fig. 2) plus an unrepaired ball mark were randomly assigned to the marks within each location and repaired. All ball marks were repaired according to repair tool manufacturers’ directions. The knit/twist GCSAA method for the TT was employed because of its widespread use on golf courses across the country. Briefly, the tongs were inserted vertically to nearly the complete depth of the tongs starting at the back side of the mark, and a twisting/weaving action was used four to five times around the perimeter until the turf canopy had enclosed the ball mark. The ATT was inserted at the back of the mark and by pressing down on the head of the tool a lifting action was used to lift the center of the mark three to four times around the perimeter and lightly tamped flat. For comparison, the WGT was chosen for this study because golfers often have the device in their pocket as it can be used for launching golf balls from teeing grounds as well as for ball mark repair. Golf ball marks were repaired by inserting the WGT around the mark four to five times until the turf canopy completely enclosed the ball mark. The GFW was pushed into the ball mark surround four to five times at a 45° angle, starting at the back of the mark and pushing the turf back into the disturbed area. Each newly repaired ball mark was lightly tamped flat after each repair tool was used.
Fig. 2. (A) Left to right, traditional tool employed when using the GCSAA ball mark repair method, angled traditional tool, standard wooden golf tee, GreenFix wizard, and a circle representing an unrepaired ball mark. (B) Front view of tools showing the angular nature of the angled tool and the push lever of the GreenFix Wizard. Assessing Ball Mark Recovery Data were collected for visual scar injury (SI) or appearance of the scar area at 2, 5, 7, 10, 14, 21, and 28 days after repair (DAR). Scar injury was rated on a 0 to 10 scale where: 0 = severe turf injury, complete absence of turf, no evidence of scar healing and/or the presence of a crater; 5 = relatively smooth surface with necrotic turf; and 10 = full turf closure, a completely healed and recovered mark with a smooth surface. An SI rating ≥ 8 was considered acceptable. Average scar area was calculated by measuring each mark with a translucent ruler in two perpendicular directions to the nearest millimeter and calculating an average diameter which was used to calculate the area of a circle. The area of each ball mark was used because the majority (> 85%) of the ball mark scars were circular in shape. Relative ball mark cavity volume was determined for eight representative marks in each location by placing a thin sheet of plastic food wrap over the ball mark and pouring dry fine sand into the depressed area until the sand was level with the green surface. The sand was tightly wrapped and taken to a laboratory and weighed. Within each area, repair tools were arranged in a completely random design with eight replications of each treatment. Statistical analyses were performed using the general linear model procedure in SAS statistical analysis software (SAS Institute Inc., Cary, NC). Each study area was analyzed independently and treatment means for individual dates separated using Fisher’s protected least significant difference (LSD) t-test at (P < 0.05). Repair Tool Affects Scar Area and Recovery Initial ball mark volumes for the soft and firm surface areas were highly significant. The mean sand masses were 9.08 and 5.01 g for the soft and firm surfaces, respectively, indicating that increased moisture in the soft area resulted in larger initial ball mark volumes and therefore potentially prolonging ball mark recovery time. Previous research has also shown that softer putting green surfaces due to a combination of low traffic, increased organic matter, and a lack of topdressing can result in increased initial ball mark volumes (2). Ratings for SI at both study sites ranged from to 0.8 to 9.9 and rating values generally increased with time as turf recovery progressed (Table 1). All repair tools resulted in a smooth surface immediately following repair with little or no disruption visible and relative rating trends among tools were similar for both study areas. By the first rating date, all ball marks repaired with a tool or not resulted in small necrotic spots where the ball mark had previously been repaired. This is consistent with other studies (2,6). By 10 DAR, the GFW and TT had reached acceptable SI levels, ≥ 8, for the soft area. When averaged across all rating dates for the soft area, the GFW and the TT had the highest SI values with ratings of 7.8 and 7.3, respectively (Table 1). This was followed by the ATT, 6.4, which was superior to either the WGT or unrepaired marks with ratings of 5.4 and 5.0, respectively. When comparing tools across time, the GFW was in the highest statistical category on all 7 rating dates, whereas the TT using the traditional method was in this category on 5 of 7 dates. By 21 DAR, all tools resulted in SI ratings ≥ 8.0, which from a practical standpoint would mean that the scar was barely visible from eye level. There was a similar trend among tools for the firm area with slightly, 0.1 to 0.3, lower rating values observed for some tools on some dates. By 10 DAR, the GFW and TT had reached acceptable levels of SI for the firm areas. When averaged across all rating dates for the firm area, the GFW and the TT had the highest SI with 7.8 and 7.1, respectively. However, the TT was not significantly different than the ATT for the firm area. Overall, using the TT with the traditional repair method or the GFW generally resulted in highest SI ratings while the unrepaired ball mark or using a standard length wooden golf tee resulted in the lowest values. Table 1. Creeping bentgrass visual surface injury as affected by various repair tools on two areas with contrasting surface firmness and moisture contents.
v Initial surface soil water contents were 28 and 20% and surface firmness values were 100 and 145 gmax using the 0.5-kg hammer on the Clegg Impact Soil tester for the soft and firm areas respectively. w Surface injury was rated on a 0 to 10 scale where: 0 = severe turf injury, complete absence of turf, no evidence of scar healing and/or the presence of a crater; and 10 = full turf closure, a completely healed and recovered mark with a smooth surface. An SQ rating ≥ 8 was considered acceptable. x GFW = GreenFix Wizard, TT = Traditional tool, ATT = Angled traditional tool, WGT = Wooden golf tee. y Means in the same column followed by the same letter are not significantly different according to Fisher’s protected LSD (P = 0.05) and are the means of eight replicates. For ball mark scar area, the scars were largest and most pronounced 2 DAR with scar areas ranging from to 205 to 640 mm² (Table 2). Ball mark scars left unrepaired in the soft area were substantially larger (640 vs. 459 mm²) than those in the firm area. For recovery, ball mark scar areas followed similar trends for the SI ratings. As expected, scar area decreased over time and by 28 DAR in both areas, all tools resulted in equivalent scar areas which ranged from 0 to 65 mm². Significant differences were observed, however, early in the study. For example, at 5 DAR, scar areas ranged 156 to 509 mm² in the soft area and 210 to 356 mm² in the firm area. For both areas the lowest numerical scar area was measured for the GFW, although not statistically different from the TT on any measurement date. This trend among tools persisted for the first 14 DAR and by 21 DAR the GFW was equal to both long-tong tools with scars ranging from 8 to 36 mm² in the soft area and 15 to 31 mm² in the firm area. This is consistent with a previous study (6) reporting that using tools with the push technique, such as the GFW, resulted in no significant difference in ball mark diameter compared to using a standard long-tong tool and the traditional method. Again the unrepaired ball mark and the WGT were statistically similar on all dates except 2 DAR on the soft surface. By comparison the scar areas for the unrepaired marks were 123 and 62 mm² in the soft and firm areas, respectively. One of the worst performing tools in this study was the WGT which was similar to an unrepaired mark on all measurement dates in the firm area and 6 of 7 dates in the soft area. Additionally, the ATT was not substantially different from the unrepaired marks on 4 of 7 measurement dates for the soft area and all dates in the firm area. Aside from improving surface smoothness by reducing the scar cavity, it appears there is no major benefit to using the ATT and WGT to repair ball marks. Table 2. Creeping bentgrass ball mark scar area as affected by various repair tools on two areas with contrasting surface firmness and moisture content.
v Initial surface soil water contents were 28 and 20% and surface firmness values were 100 and 145 gmax using the 0.5 kg hammer on the Clegg Impact Soil tester for the soft and firm areas, respectively. w Ball mark scar area was calculated by measuring the diameter of each scar in two perpendicular directions. For comparison the diameter of a standard golf ball is 42.7 mm which is equivalent to an area of 1432 mm². x GFW = GreenFix Wizard, TT = Traditional tool, ATT = Angled traditional tool, WGT = Wooden golf tee. y Means in the same column followed by the same letter are not significantly different according to Fisher’s protected LSD (P = 0.05) and are the means of eight replicates. Minimal ball mark scarring was visible 28 DAR for all tools, including the unrepaired ball mark. Researchers at Mississippi State (6) reported that it took 48 days for ball marks to be considered healed on ‘MS-Supreme’ bermudagrass (Cynodon × magenissii Hurc.) greens using various tools and methods while researchers at Rutgers University (7) found that it took 41 days for unrepaired ball marks to be considered healed on ‘Pennlinks’ creeping bentgrass. The relatively fast recovery, ≈ 28 days, in the present study may be due to a lack of real/simulated traffic, environmental conditions, or a slightly higher mowing height. Maximizing Ball Mark Recovery It is clear from this study that many factors affect ball mark recovery. Surface firmness and repair tool both play an important role in recovery time. Maintaining drier and firmer surfaces by rolling, irrigating deep and infrequently, and using management practices that decrease organic matter such as core cultivation and sand topdressing could provide better resistance to ball marks and decrease the recovery period by ensuring smaller initial ball mark scar cavities. In this study, the TT and the GFW resulted in the fastest ball mark recovery and overall better SI. The longest recovery was associated with the WGT, which was similar to an unrepaired mark on most rating dates. The ATT was not significantly different from the unrepaired marks on 4 of 7 measurement dates for the soft area and all dates in the firm area. Future studies should evaluate the effect of additional ball mark repair tools and the impact of nutritional programs on ball mark recovery. Acknowledgments This research was supported by Mid-West Regional Turf Foundation and the GreenFix Golf Inc. Grateful appreciation is extended to Mr. Eddie Gene Walker for his technical assistance in helping us create and repair the ball marks at the initiation of this study. Literature Cited 1. Beard, J. B. 2002. Turf Management for Golf Courses, 2nd Edn. Ann Arbor Press, Chelsea, MI. 4. Linde, D. 2005. Assessing golf course conditions in New Zealand. Golf Course Man.73:110-113. 5. Lush, W. M. 1985. Objective assessment of turf cricket pitches using an impact hammer. J. Sports Turf Res. Inst. 61:71-79. 7. Murphy, J. A., Lawson, T. J., and Clark, J. 2003. Ball marks on bentgrass. USGA Turfg. Environ. Res. Online 2:1-6. 8. USGA Green Section. 1993. USGA’s recommendations for a method of putting green construction. USGA Green Sec. Rec. 31:1-33. |
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