The Evolution of Soil Wetting Agents for Managing Water Repellency in Soils.
D. Moore, S. J. Kostka, M. Franklin, L. L. Lennert, and R. A. Moore. Aquatrols, 843 East Parkway, Salt Lake City, UT 84106
Development of water repellency in soils and growing substrates is increasingly recognized as the norm rather than an exception. Consequences of water repellency include reduced distribution uniformity and irrigation efficiency, suboptimal growing conditions, increased runoff, preferential flow, pollution potential and increased requirement for water and other inputs. Research indicates that use of surfactants is a practical and effective strategy for addressing water repellency in various growing systems. Since their invention in the mid-1950’s, soil wetting agents/soil surfactants offerings have evolved from a single "purpose formulated" product and several detergents to over 70 products specifically formulated for use in turf management, ornamental horticultural and agriculture. The use of soil wetting agents has also grown dramatically. Turf industry surveys show more than 90% of golf course superintendents using soil wetting agents for one reason or another. Nearly 100% of North American producers of commercial peat or bark based growing substrates use a soil – or “media” - surfactant to address the inherent water repellency of those substrates. A large percentage of European substrate producers do the same. Agricultural use is also increasing. Chemistries used for soil and media surfactants have evolved over the years for efficacy and environmental safety reasons. There are commonalities in the classes of surfactant chemistry used in many of today's soil/media surfactants. However modifications of structure and/or formulation can have profound effects on performance. The evolution of surfactant formulations and related research has not been well documented resulting in confusion and poor understanding of their effective use for managing water repellency and distribution uniformity issues in various soils. Documenting the evolution of soil/media surfactant formulations and research may allow further research and management strategies for water repellency/water use efficiency to benefit from what has previously been learned.