Wetting Agents
Tyler Carr
Assistant Professor and Turfgrass Extension Specialist
Introduction:
Wetting agents are commonly used to increase moisture uniformity and mitigate the effects of localized dry spot in sand-based rootzones. New wetting agents are routinely developed and tested to ensure efficacy and limited phytotoxicity.
Materials and Methods:
This experiment was initiated on July 12, 2023 on a newly-established sand-based putting green consisting of ‘Pure Distinction’ creeping bentgrass. Fourteen experimental wetting agents and an untreated control treatment were applied in seperate plots at a rate of 6 fl oz/1000 square feet in a carrier volume of 2 gallons/1000 square feet. Within one hour of application, 0.25 inches of water was applied to the experimental area.
The wetting agents will be reapplied on 21-day intervals until five applications have been made (applications on days 0, 21, 42, 63, and 84). Irrigation will be applied at 50% of the normal rate for weeks 6-8 so treatments can be evaluated across a range of irrigation regimes.
Evaluations:
- Volumetric water content (VWC) every 14 days at 1.5 and 4.8 inches
- 9 measurements per plot to assess soil moisture uniformity
- Phytoxicity evaluated 2 and 7 days after treatment (DAT) application using dark green color index (DGCI), a metric of turfgrass color
Results:
Soil moisture:
- Treatments did not differ in VWC 14 days after the original application
- Repeated applications are likely necessary to elucidate treatment effects
Phytoxicity:
- Treatments differed in DGCI 2 DAT, with many treatments significantly different than the untreated control (Figure 1). This implies that some phytoxicity was present in those treatments. All phytoxic effects were alleviated by 7 DAT.
Figure 1. Dark green color index values for 14 experimental wetting agents and an untreated control two days after treatment application on a sand-based ‘Pure Distinction’ creeping bentgrass putting green in Columbus, OH. Greater values indicate darker green turfgrass, and bars represent the least significant difference for detecting treatment differences (P ≤ 0.05)
Conclusions:
Evidence from previous research indicates that season-long wetting agent programs are beneficial in alleviating localized dry spot and increasing moisture uniformity on sand-based putting greens. While this study is only at its infancy, monitoring a wetting agent program throughout the season will help companies identify products that perform best in Ohio.