Effects of Misting and Subsurface Air Movement on Bentgrass Putting Greens

Preferential use of creeping bentgrass [Agrostis stoloniferous L. var. palustris (Huds.)] on golf putting greens has expanded into the hotter, more environmentally stressful regions of the southeastern United States where turfgrass decline is problematic during summer months. Methods of reducing temperatures in the putting green microclimate would enhance bentgrass survival under heat stress conditions. The objectives of this study were to evaluate the bentgrass putting green microclimate under combined misting and/or subsurface fan systems with surface fans. Field studies were conducted in the summers of 2001 and 2002 on a ʹCrenshawʹ creeping bentgrass putting green located in Clemson, SC. Treatments consisted of surface fan only, surface fan plus misting, surface fan plus subsurface fan, and surface fan plus misting and subsurface fan. Fan treatments were applied from 1100 to 1500 h on days when temperatures were >=29.5°C, there was no visible cloud cover, and wind speed < 1.0 m s^-1. Surface fan plus misting treatments reduced putting green canopy, soil surface, and soil temperatures by as much as 9, 7, and 6°C, respectively, while increasing canopy relative humidity and soil moisture content. Benefits were generally observed over a range of 5 m from the fan. These treatments demonstrate great potential for improving canopy and soil microclimate conditions influencing bentgrass survival in a heat stress environment. Surprisingly, the use of subsurface fans did not enhance the cooling effect provided by surface fans. Fan/mist systems should be investigated further to determine possible disease occurrence during extended use periods.