Surfactants Increase Uniformity of Soil Water Content and Reduce Water Repellency on Sand-Based Golf Putting Greens

Water repellency and related localized dry spots are common problems on sand-based root zones often used for golf putting greens. The objective of this study was to quantify the effect of three commonly used surfactants applied to a sand-based root zone on turfgrass visual quality and drought symptoms, soil water content and uniformity, and soil water repellency. In 2007 and 2008, a study was conducted in Wisconsin on a creeping bentgrass golf putting green with a water-repellent sand soil. Prolonged periods of drought occurred in both years. Treatments included three surfactants and two controls, one irrigated at 30% of potential evapotranspiration (ETp) and a second irrigated at 100% of ETp. The surfactant treatments were irrigated at 30% of ETp. Soil moisture was measured weekly in each plot on a 5 × 5 30-cm grid pattern, along with visual estimates of area exhibiting drought symptoms and turfgrass visual quality. Soil water repellency was measured before and at the conclusion of each growing season. In 2007, the surfactant treatments maintained visual quality lower than the well-irrigated control treatment but greater than the reduced-irrigation control treatment. In 2008, substantial drought symptoms appeared on all surfactant treatments, which recovered faster than the reduced-irrigation control treatment. Soil water contents of surfactant treatments were similar to each other and the reduced-irrigation control on most testing dates. During periods of drought, surfactant-treated soils had the greatest uniformity of moisture content and lowest water repellency at the end of each growing season. These results indicate that use of these surfactants can reduce water use while improving visual quality compared with untreated areas, prevent localized dry-spot development, and increase moisture uniformity in sand-based golf putting green root zones.