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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100 GOLF COURSE MANAGEMENT 04.14 Fe(II) is mobilized from the root zone to the gravel layer, the alkaline pH causes Fe(II) to rapidly oxidize to Fe(III) (3). Finally, the third scenario is unique in that the alka - line root zone pH would not seem to favor Fe(II), yet there is evidence of iron mobili - zation and accumulation at the sand/gravel interface. One possible explanation for this is that under certain conditions, iron sulfde can react with oxygen and water to produce sulfuric acid as a byproduct: 2FeS 2 + 7O 2 + 2H 2 O g 2FeSO 4 + 2H 2 SO 4 . In this scenario, it is possible that the acidity produced from this reaction results in mobilization of iron from the root zone above, creating a positive feedback cycle where iron is continually reduced and mobi - lized downward, where it accumulates at the textural boundary. Do management practices produce layers? Although we have encountered many sites with cemented layers (approximately 33% of a random sample), the majority of two-tiered putting greens do not exhibit layer forma - tion. Therefore, there must be management practices or chemical conditions that are causing this layer to form in certain loca - tions, but not others. Future research should identify the contributions of iron and man - ganese from fertilizer, irrigation water and root-zone mineralogy. Root-zone mixes that are initially high in iron or manganese may be predisposed to layer formation, especially if the root zone is acidic. However, our pre - liminary data suggest that applying modest rates of iron for color enhancement can ac - count for over 300 times the amount of iron needed to account for the layer formation. Ir - rigation inputs of iron are not likely to pro- vide enough iron to account for the layer, even in water rich with iron. Therefore, until we know more about how these layers form, we are recommending that people exercise caution when applying iron and manganese fertilizers. Traditional soil sampling of the upper 6 to 8 inches (15.2-20.3 centimeters) is inad - equate to detect problems that may be occur- ring deeper in the profle. Taking full-profle samples periodically using a sharpened PVC pipe is a great way to monitor potential lay - ering issues deep in the profle that could be developing over time (5). Options for removing the layer appear to be limited and warrant further study. Physi - cal removal or disturbance by deep-tine aeri- fcation would help alleviate drainage issues, but these are very invasive and labor-inten - sive processes. Applying anything to chemi- cally dissolve iron could potentially make the layer worse; if these chemicals are not prop - erly leached out of the root zone, they could mobilize even more iron and make the layer thicker. We plan to continue to investigate methods for removing the layer and prevent - ing its formation. Funding This research was graciously funded by the United States Golf Association, the Wisconsin Turfgrass Association and the Wisconsin Golf Course Superintendents Association. Acknowledgments We would like to thank Drs. Jim Mur- phy, Norm Hummel, Bernd Leinauer, Eric Roden, Jim Bockheim and Micah Woods for their expertise and assistance. This work would not have been possible without contri - butions from Scott Nair, Jim Russell, Heidi Obear, Gloria Ambrowiak, Nick Bero, Shane Griffth, Brad DeBels, Matt Fish, John Gil - lis, Josh Horman, Andy LeBeau and John Krueser. Literature cited 1. Bockheim, J. 2011. Distribution and genesis of ortstein and placic horizons in soils of the USA: A review. Soil Science Society of America Journal 75:994-1005. 2. Gotoh, S., and W. Patrick. 1974. Transformation of iron in a waterlogged soil as infuenced by redox potential and pH. Soil Science Society of America Journal 38:66-71. 3. Lapen, D.R., and C. Wang. 1999. Placic and ort - stein horizon genesis and peatland development, southeastern Newfoundland. Soil Science Society of America Journal 63:1472-1482. 4. Mehnert, C., and L. Wege. 2008. Effects of standing water on nutritional features of a golf green [in Ger - man ]. Greenskeepers Journal 39:37-40. 5. Obear, G.R. 2013. Iron layering in two-tiered putting greens. Golfdom 69(1):55-57. 6. Prettyman, G., and E. McCoy. 2003. Profle layering, root zone permeability, and slope affect on soil water content during putting green drainage. Crop Science 43:985-994. 7. Soil Survey Staff. 2010. Keys to Soil Taxonomy. 11th ed. USDA-NRCS Agriculture Handbook No. 436. U.S. Government Printing Offce, Washington, D.C. 8. Taylor, D., S. Nelson and C. Williams. 1993. Sub-root zone layering: Effects on water retention in sports turf soil profles. Agronomy Journal 85:626-630. Glen R. Obear is a research intern and graduate student and Douglas J. Soldat ( is an associate professor in the department of soil science at the Univer - sity of Wisconsin-Madison. • Layers of cemented soil with reduced perme- ability have been found at textural boundaries in sand root zones. The layers form across a broad range of climates and geographic regions. • These layers are enriched with organic matter and are cemented primarily by iron, though manganese may also act as a cementing agent. • The layers are found at textural boundaries, usu - ally where fine particles sit above large particles. Water is retained in the finer-textured layer, and reduced Fe(II) is exposed to oxygen in the layer below, causing it to oxidize to Fe(III). • Layers are more likely to form in low-lying areas, and acidic pH conditions may increase the rate of formation. Layering may be augmented by iron fertilization. RESEARCH SAYS 090-101_April14_TechwellCuttingEdge.indd 100 3/18/14 2:54 PM

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