Influence of Height of Cut and Mowing Frequency on Ball Roll Distance and Turfgrass Quality.

Golf course putting greens are arguably the most intensely managed playing surface on golf courses.  Ball roll distance (BRD), often referred to as “green speed”, and trueness of the ball’s roll across a green have a major impact on the playability of putting surfaces.  The objectives of this study are:  1) to determine the effect of mowing frequency and height of cut on ball roll distance on golf course greens; 2) to determine the impact of mowing on turfgrass quality. Three field studies were initiated in the spring of 2015 and repeated in 2016 at the Joseph Valentine Turfgrass Research Center located in University Park, PA.  Trials were conducted on mature stands of ‘A-4’ creeping bentgrass (CBG; Agrostis stolonifera L.), 90/10 ‘Bridgeport II’ fine leaf fescue (FLF; Festuca rubra L.)/‘Alister’ colonial bentgrass (Agrostis capillaris L.), and annual bluegrass (ABG; Poa annua L.) putting greens.  Plots measured 1.2 x 2.7 m and were arranged in a randomized complete block design with a 3 x 3 factorial treatment structure.  The main factors included height of cut and mowing frequency. For experiments conducted on annual bluegrass and creeping bentgrass, putting greens height of cut (HOC) were set to a bench height of 2.1 mm, 2.5 mm, and 2.9 mm. For the experiment conducted on fine fescue, HOC’s were 4.0 mm, 4.5 mm, and 5.0 mm.  Individual plots were mowed either once, twice, or four times per day.  The main effects of HOC and FREQ were significant on most rating dates over the two week study and few interactions were observed. On most rating dates and for all turfgrass species, turf mowed at the lowest HOC and at the highest FREQ generally had the greatest BRD. Mowing frequency had the greatest impact on BRD with maximum distances of 365 cm, 347 cm, and 344 cm observed for treatments mowed 4 times per day on CBG, ABG, and FLF, respectively. The HOC had less impact on BRD with differences between the lowest and highest HOC observed on 79%, 43% and 0% of the rating dates on ABG, CBG, and FLF, respectively. Interestingly, BRD was shorter in the middle HOC treatments on several rating dates when compared to turf mowed at the highest and lowest HOC. On dates where differences were present, turfgrass quality across all species was lowest in plots mowed at the lowest height and at the highest frequency.