Dyer, Don Wesley (2017-08). Sand-capping Depth and Subsoil Influence on Turfgrass Establishment, Performance, and Irrigation Requirements. Master's Thesis.
Thesis
Management of golf course fairways and athletic fields can become especially difficult where fine-textured native soils become degraded due to high sodium levels in irrigation water. The sodium causes the clay particles in the soil to disperse, effectively destroying the soil structure. Common problems that arise in these scenarios include excessive fairway wetness, very slow drainage, poor aeration, and severe compaction of highly trafficked areas, all of which result in poor quality turf. To improve turf surfaces, sand-capping of problem fairways and fields has gained popularity in recent years. No recommendations currently exist for specific depths or particle size distribution of capping sands, and less than optimal depths of sand are often used due to the significant cost of renovation. The recommended depth depends on the physical properties of the sand, environmental conditions, and providing a balance of water to air-filled porosity for optimal turf growing conditions. If a capping depth that is too shallow or too deep is chosen, turf quality can be negatively affected. Our research results indicate the overall turf quality and performance behaved differently as a result of the subsoil used. The sand-cap treatments atop the clay loam subsoil maintained a higher overall quality and health throughout the two growing seasons of the study. Furthermore, we found that the shallower capping depth of 10 cm out-performed the deeper 20 cm capping depth in regards to turf quality and cover which was primarily due to the higher moisture contents maintained near the surface and the ease of root development into the underlying subsoil. Moisture management of sand-capped areas greatly differs from other construction methods, such as the USGA-design construction. With the information gained from this research, this study may lend insight into the development of recommendations for the physical properties of capping sands and how those properties should differ from those currently used for sand in USGA-design putting greens.
Management of golf course fairways and athletic fields can become especially difficult where fine-textured native soils become degraded due to high sodium levels in irrigation water. The sodium causes the clay particles in the soil to disperse, effectively destroying the soil structure. Common problems that arise in these scenarios include excessive fairway wetness, very slow drainage, poor aeration, and severe compaction of highly trafficked areas, all of which result in poor quality turf. To improve turf surfaces, sand-capping of problem fairways and fields has gained popularity in recent years. No recommendations currently exist for specific depths or particle size distribution of capping sands, and less than optimal depths of sand are often used due to the significant cost of renovation. The recommended depth depends on the physical properties of the sand, environmental conditions, and providing a balance of water to air-filled porosity for optimal turf growing conditions. If a capping depth that is too shallow or too deep is chosen, turf quality can be negatively affected. Our research results indicate the overall turf quality and performance behaved differently as a result of the subsoil used. The sand-cap treatments atop the clay loam subsoil maintained a higher overall quality and health throughout the two growing seasons of the study. Furthermore, we found that the shallower capping depth of 10 cm out-performed the deeper 20 cm capping depth in regards to turf quality and cover which was primarily due to the higher moisture contents maintained near the surface and the ease of root development into the underlying subsoil. Moisture management of sand-capped areas greatly differs from other construction methods, such as the USGA-design construction. With the information gained from this research, this study may lend insight into the development of recommendations for the physical properties of capping sands and how those properties should differ from those currently used for sand in USGA-design putting greens.
