Golf Course Management

APR 2014

Golf Course Management magazine is dedicated to advancing the golf course superintendent profession and helping GCSAA members achieve career success.

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96 GOLF COURSE MANAGEMENT 04.14 Iron-cemented layers in putting green soils Cemented layers, which inhibit drainage, can occur in putting greens where different textures, such as sand and gravel, meet. Two-tiered putting green profles fea- ture a sand root zone that sits above a layer of gravel, creating a textural boundary where water is perched or preferentially retained (6). The greater the difference in particle sizes, the more water is retained in the fne-textured layer above (8). Hard, brittle, cemented layers have been observed to form at textural bound - aries in two-tiered putting greens. The layers severely impede subsurface drainage and re - sult in deterioration of turfgrass quality due to persistently wet, anaerobic conditions in the root zone. These layers tend to be reddish- orange, suggesting that they are cemented by iron-oxide minerals, but to date there are no published reports describing the chemical na - ture of these layers. Similar layers have been documented in putting greens in Germany (4), but the authors did not describe the chem - ical properties of the layers. We frst learned of this issue in 2008 and thought it was an isolated, rare phenomenon. However, an unrelated study that involved sampling the full profles of two-tiered put - ting greens across the United States revealed that this issue is widespread. We found ce - mented layers in 12 of the 36 profles that we sampled, and since 2011 we have observed or received reports of more than 30 sites with similar layering issues in at least 16 states in the U.S., as well as in Germany, England, Sweden, Vietnam and the Philippines. Al - though some of these sites have greens built following United States Golf Association Glen R. Obear Douglas J. Soldat, Ph.D. Study sites Site name Mean annual precipitation (inches) Root zone age (years) Turfgrass species Midwest 27 35 Agrostis stolonifera, Poa annua Northeast 35 25 A. stolonifera, P. annua Southeast 1 36 14 A. stolonifera Southeast 2 53 16 Cynodon dactylon × transvaalensis Oceania 11 9 Paspalum vaginatum Table 1. Sites included in this study. Mean annual precipitation data from February 1981 through November 2012 were obtained through the National Climatic Data Center. This research was funded in part by the United States Golf Association. recommendations, in many instances, these layers can be found in soil profles that do not follow USGA recommendations. Ex - amples include sand-based soccer felds with gravel drainage layers, sand bunkers with gravel-flled drain trenches, and gravel-flled peripheral ("smile") drains adjacent to one- tiered putting greens (sand over compacted subsoil). The primary objective of this study was to identify the chemical properties of these cemented layers to determine what they have in common and how they are different. Characterizing the chemical properties of these layers in golf putting greens is the frst step toward developing effective strategies to manage or prevent their formation. Materials and methods Five sites with cemented layers were iden- tifed through communication with USGA agronomists, golf course superintendents and other researchers (Table 1). To maintain con - fdentiality, sites were identifed only by the geographic region in which they are located. Each site featured sand-based putting greens with a gravel drainage layer. Golf course su - perintendents from each site collected three putting green soil profle samples in PVC pipes (2-inch [5-centimeter] inside diameter, 25-inch [64.7-centimeter] length) from areas known to have cemented layers. The samples included the full soil profle from the turf - grass to the gravel drainage layer, with the exception of Southeast 2, which was in the midst of renovation and had removed the top 8 inches [20.3 centimeters] of the profle. Soil profle samples were mailed to our laboratory for analysis, where PVC pipes were cut open vertically with an oscillating 090-101_April14_TechwellCuttingEdge.indd 96 3/18/14 2:54 PM

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