Effect of Late-Fall Wetting Agent Application on Winter Survival of Ultradwarf Bermudagrass Putting Greens.

Effect of Late-Fall Wetting Agent Application on Winter Survival of Ultradwarf Bermudagrass Putting Greens.

E. J. De Boer, D.E. Karcher, M.D. Richardson, and J.H. McCalla

Winter injury is a common problem for transition zone ultradwarf bermudagrass (Cynodon dactylon x C. transvaalensis) putting greens. One possible cause of winter injury is plant tissue desiccation. Desiccation injury can be caused by the formation of hydrophobic soils resulting in irregular shaped patches of injured turf. Wetting agents are commonly applied to actively growing ultradwarf greens to relieve or prevent plant stress from hydrophobic soils. Less is known about the effects of a late-fall (late-season) wetting agent application to dormant bermudagrass greens. This research aims to quantify any reduction in winter injury by making a late-season wetting agent application to a dormant ultradwarf bermudagrass putting green. Single applications of three commonly used wetting agents made to a sand-based ‘Tifeagle’ ultradwarf bermudagrass putting green were compared to an untreated control. Wetting agents were applied at label rate and twice the label rate to quantify any residual benefits of making a more concentrated application. Spring green-up was determined through visual ratings and by quantifying percent green turfgrass coverage through digital image analysis. Soil volumetric water content was monitored bi-weekly using a Spectrum TDR-300 (Spectrum Technologies Inc., Aurora, IL). Water drop penetration tests were conducted on air-dried soil cores 2 weeks after application and again the following spring to quantify any reductions in hydrophobicity compared to the untreated control. On multiple dates during the spring of 2016, plots that received a wetting agent produced significantly greener turfgrass when compared to the control. These effects were not significant during 2017. Wetting agents significantly reduced water drop penetration times but doubling application rates had no significant effect on water drop penetration times. This research suggests that a golf course without the option of irrigating during the winter, may benefit through the one-time application of a wetting agent in the late-fall.