Bermudagrass and Zoysiagrass Cultivar Selection: Part 2, Divot Recovery

Golfers commonly remove turf and soil when swinging a golf club causing a divot in the turf. Divot recovery is an important factor that should be considered when selecting a species or cultivar for use on golf course tees or fairways. There are few reports directly comparing the divot recovery among bermudagrass (Cynodon spp. Rich.) and zoysiagrass (Zoysia spp. Willd.) cultivars. Therefore, the objective of this experiment was to quantify divot recovery of several bermudagrass and zoysiagrass cultivars in a combined field experiment. Divot recovery was evaluated on four collection dates for five cultivars of bermudagrass and seven cultivars of zoysiagrass. Cultivars generally with the fastest time to 50% recovery were ‘Princess 77’ and ‘Riviera’ bermudagrass and ‘Palisades’ zoysiagrass. Generally, the cultivars with the slowest time to 50% recovery were ‘Meyer’ and ‘Zenith’ zoysiagrass. Additionally, ‘Tifway’ bermudagrass had similar divot recovery times to ‘El Toro’ and Palisades zoysiagrass. These results demonstrate that differences and similarities exist among bermudagrass and zoysiagrass cultivars for divot recovery, and golf course superintendents can use this information to better select cultivars that could improve surface playing conditions. Introduction A swing by a golfer while attempting to strike a golf ball commonly displaces an area of turf and soil that is referred to as a divot (7). Divots created by a golf stroke are a regular occurrence on golf course fairways or tees (7). It has been estimated that approximately 0.21 ha of turf are removed by divoting from a bermudagrass golf course fairway each year (7). The number, size, and length of time divots exist on a tee or fairway depend on species (1). Divot recovery describes the rate of recovery of a turfgrass from divoting and is an important factor that should be considered when selecting a species or cultivar for use on golf course tees or fairways and other athletic playing fields. There have been few studies to quantify differences in recovery rates between species, but popular turf textbooks (1,10) rank bermudagrass (Cynodon spp.) as having superior recuperative capacity or rate compared to zoysiagrass (Zoysia spp.). Karcher et al. (4,5) examined the divot recovery on native soil for numerous bermudagrass and zoysiagrass cultivars in separate field studies. Karcher et al. (4) reported that Riviera, Princess 77, and ‘Patriot’ bermudagrass each had relatively fast divot recoveries for the cultivars tested during the first year of the experiment. However, in the second year’s results, there were no differences among Princess 77, Riviera, Tifway, ‘Tifsport,’ and Patriot bermudagrass. In a separate study evaluating zoysiagrass cultivars, Karcher et al. (5) reported that Palisades, ‘Cavalier,’ Zenith, and ‘Zorro’ zoysiagrass all had similar divot recovery, while Meyer had a significantly slower divot recovery. El Toro had the fastest divot recovery in one year of the study, but had a relatively slower divot recovery in another year. Although bermudagrass and zoysiagrass were evaluated in separate experimental areas by Karcher et al. (4,5), their data 30 June 2011 Applied Turfgrass Science suggest that the recuperative capacity of these two species may not be as different as previously reported (1,10). For example, in 2004 Karcher et al. (4) reported that Riviera bermudagrass required 4.6 days to reach 50% recovery, while in 2004 Karcher et al. (5) reported that Palisades zoysiagrass required 4.2 days to reach 50% recovery. It has also been reported that zoysiagrass cultivars can differ greatly in growth rate and establishment rate (6), suggesting that some zoysiagrass cultivars may also have divot recovery similar to specific bermudagrass cultivars. Therefore, the objective of this experiment was to quantify the divot recovery for commonly used bermudagrass and zoysiagrass cultivars in the same experimental field trial. Evaluating Divot Recovery This experiment was conducted at the Arkansas Agricultural Research and Extension Center, in Fayetteville, AR (36°06’N, 94°10’W, 384 m). The planting site was fumigated with methyl bromide at 549 kg/ha in April 2007 and was a Captina silt-loam soil (fine-silty mixed mesic Typic Fragiudalt) with a pH of 6.6, 1% organic matter, 105 kg P/ha, and 97 kg K/ha. Five cultivars of bermudagrass and seven cultivars of zoysiagrass were evaluated in the experiment (Table 1). Cultivar selection was based on use and availability in the transition zone and southern United States. All cultivars were established as sod in July 2007 as 1.8m by 1.8-m plots with a 0.3-m border maintained with glyphosate (2.2 kg/ha) to prevent contamination from adjacent plots. Due to limited sod availability, ‘Diamond’ zoysiagrass was initially planted as 0.5-m by 0.5-m plots until additional plant material could be propagated. Diamond zoysiagrass plugs were planted in May 2008 in the remainder of the plot area and plots were > 95% cover by August 2008. To simulate golf course fairway conditions, all plots were mowed at 1.3 cm. The experimental design was a randomized complete block design with four replications. Plots were fertilized with nitrogen using urea (460-0) at 24 kg/ha per growing month for zoysiagrass and 49 kg/ha per growing month for bermudagrass based upon input from Arkansas golf course superintendents. Simazine was applied to all plots on 21 November 2007 and 24 November 2008 at 1.1 kg/ha to control winter annual weeds. An additional application of foramsulfuron was applied on 13 April 2008 at 30 g/ha to control annual bluegrass (Poa annua L.). Table 1. Cultivar, experimental notation, and species of bermudagrass and zoysiagrass used in this study to quantify divot recovery in Fayetteville, AR. x The cultivars Princess 77 bermudagrass and Zorro zoysiagrass were each evaluated using two experimental notations before the cultivars were released for commercial use. Cultivar Experimental