Page 15 - GM Spring 2023

Agents 101 Demonstration of the impact surfactants can have on contact angle.
agent to apply. If your golf green’s profile is heavy clay or poorly drained, the anionic surfactant may be an appropriate choice to survive the weekend as it will reduce runoff and improve infiltration. A great strategy when deciding upon a wetting agent is to understand that particular product’s performance details. Three metrics are commonly used to assess the performance characteristics of wetting agent products: Draves Wetting test, surface tension, and contact angle.
The Draves Wetting test reveals how long it will take water to penetrate a hydrophobic surface when mixed with a wetting agent. A good rule of thumb is any material having a Draves rating of 45 seconds or less should be considered an effective wetter (strong ability to rehydrate dry soil).
Contact angle data shows how well a droplet can spread out on surfaces Contact angle data is measured by using a microscope to examine a drop of water combined
with a wetting agent on wax paper. The greater the ability to spread out, the greater ability to wet. An untreated drop of water on a waxy surface has a contact angle of roughly 70-90 degrees. Some wetting agents when mixed with water will reduce that contact angle to the high 20s or low 30s, giving the droplet high spreadability and wetting capability.
As mentioned previously, anionic surfactants have a very low contact angle and great penetrating ability. Anionic surfactants typically have a
GreenMaster • CGSA • 15