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VIRGINIA TURFGRASS JOURNAL: Xunzhong Zhang, Ph.D., Mike Goatley, Ph.D., Rose Harvey, and Ben Goddard – School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA

Wetting agents are a primary management strategy utilized by most golf courses in putting green water management. Adding wetting agents can reduce the surface tension of water and overall soil water repellency, thus allowing water to better infiltrate and percolate through potentially hydrophobic soils. However, due to the variation in soil and turf, especially thatch layers so commonly encountered on intensively managed putting green turf, soil moisture status may vary across different areas of the putting greens, resulting in dry spots and decline in turf quality and uniformity, especially during summer stress. The objective of this study was to evaluate effects of the wetting agent Fleet100 on turf quality, physiological fitness, and root growth in creeping bentgrass putting greens during summer stress.

We carried out this study at the Virginia Tech Turfgrass Research Center in Blacksburg, VA, during 2021–2022 on a creeping bentgrass putting green managed as a standard golf putting green turf with regard to mowing, fertility, and surface irrigation. There were two treatments: HydroMAX surfactant Fleet 100 (Harrell’s, Lakeland, FL) and an untreated control and each treatment was replicated four times in a randomized block design. Fleet100 was applied at 5 fl oz/1000 ft2 monthly and both treatments received identical fertilization at 0.15 lb N/1000 ft2 biweekly. Irrigation was provided in the range of 0.125″ and up to 0.25″ water following application. The trials lasted for 12 weeks from June 8 through August 31 and included a total of three treatment applications. The grass was exposed to two dry-down cycles during mid-June and mid-July by withholding supplemental irrigation. Turf quality rating and physiology-based phenotyping methods were used to evaluate turfgrass response to the wetting agent treatments every other week. At the end of this trial, root biomass and viability were measured.

We found monthly application of Fleet100 at 5 fl oz/1000 ft2 significantly improved turf quality, leaf color ratings, leaf proline content, and chlorophyll content when compared to the control in creeping bentgrass putting greens, especially during drought stress periods. In addition, the creeping bentgrass treated with Fleet100 had greater root biomass (Fig. 2) and viability relative to control. The Fleet100 treatment also improved soil moisture content at 6-inch depth during drought stress period. The results of this study suggest monthly application of the wetting agent Fleet100 could improve soil moisture status, physiological fitness and visual quality of creeping bentgrass putting greens in Virginia and other regions with similar climate.