Soil surfactant stops water repellency and preferential flow paths

This study reports the effects of a soil surfactant on reduction and prevention of water repellency and preferential flow paths in a sandy soil of a golf course fairway, located at Bosch en Duin near Utrecht, the Netherlands. The golf course is constructed on inland dunes composed of fine sand with low organic matter content. The topsoil (0-25 cm) of the fairways exhibits an extremely water repellent behaviour resulting in the development of numerous localized dry spots during dry periods in spring and summer. The influence of surfactant treatments on the wetting of the soil was studied by measuring the volumetric water content with a hand-held Time Domain Reflectometry (TDR) device. Actual water repellency was assessed by placing water drops at regular distances on soil cores taken to a depth of 25 cm with a small (1.5 cm diameter) auger at intervals of 25 cm over a distance of 25 m across the untreated and treated parts of the fairway. Surfactant applications resulted in more homogeneous wetting of the soil profile and elimination of actual water repellency in the fairway soil. Treatments significantly increased water uptake and moisture levels of the soil and prevented the development of preferential flow paths. A visible improvement in turf quality and density was evident on the treated part of the fairway.