Issue link: http://read.dmtmag.com/i/50980
inch of well-graded root-zone material costing about $14,400 ($6,000 labor and $8,400 materials). The topdressing stops in early August to allow the recently applied topdressing to settle prior to fall use. During the first year the root-zone may not reach a depth necessary to prevent saturated surface conditions, particularly in low lying areas, but the drain tiles will prevent standing water from developing, providing a system that is better than original conditions. In the following spring the topdressing process would begin again to add the rest of the material, further increasing the systems drainage capacity. The end result is a well drained, stable, sand-based field at a fraction of the cost required for other renovation processes. The Research In 2007, two research projects were designed and initiated at the Hancock Turfgrass Research Center, East Lansing, MI, to address the feasibility of the Spartan Cap renovation process. Well- graded 90% sand – 10% silt+clay topdressing material, developed by a team of turfgrass scientists at MSU in the later 90's for athletic field construction, was utilized for the following research projects. Experiment 1: The objective of the first experiment was to evaluate the effects of cumulative sand topdressing rates and summer traffic on the fall wear tolerance and surface stability of a cool-season turfgrass stand. Findings from this body of work determined that 0.5" of topdressing applied over a 5-week period, and restricting summer traffic on a newly established turfgrass stand, will provide the greatest surface stability (shear strength) in the subsequent fall. Topdressing depths regardless of rate improved turfgrass wear tolerance (ground cover and shoot density), but aggressive rates, greater than 1.5" , diminished surface stability. Therefore, 0.5" applied over a 5-week period is suggested to provide the optimum wear tolerance and surface stability. If annual topdressing depths greater than 0.5' are desired, it is recommended that field managers spread out applications over a period of time greater than 5-weeks to avoid compromising surface stability. For instance, if 1" is the desired annual topdressing depth, this depth of sand should be applied over a 10-week period. Experiment 2: The objective of the second experiment was to establish intercept drain tile spacing, in combination with sand topdressing, necessary to improve drainage, turfgrass wear tolerance and surface stability on a sandy loam soil. Preliminary findings from this research suggest that as little as 0.5" of sand can used to improve athletic field playability by substantially decreasing the surface moisture content. Findings from this research also determined that a drain tile spacing of 13', which will substantially reduce installation costs ($22,400-28,000; material and labor), is adequate to provide sufficient drainage and stability when 1" of topdressing [$14,400; material (300 tons of sand spread across 72,000 sq. ft) and labor] has been applied. However, 2008 results suggest that if 2" of topdressing ($28,800) has been accumulated and an adequate surface slope is available (">1%,) drain tile spacing can be increased to distances greater than 20'. Drain tile installation at 20' spacing would cost approximately $14,400-18,000. It is important to note that drain tiles are necessary to prevent standing water from accumulating along sidelines and other low lying areas and therefore should not be completely excluded from the renovation process. Conservative recommendations based on this research suggest a drain tile spacing of 13' and a 2" sand topdressing layer accumulated over a two year period for a total of $66,200-71,800 (cost includes a $15,000 irrigation system). TL For more information on the Spartan Cap renovation process and specifications contact the following: Dr. John N. Rogers III Michigan State University Crop and Soil Sciences 160A PSSB East Lansing, MI 48824 (517)355-0271x1136 rogersj@msu.ed Dr. James R. Crum Michigan State University Crop and Soil Sciences 160C PSSB East Lansing, MI 48823 (517)355-0271x1134 crum@msu.edu Dr. Alec R. Kowalewski Abraham Baldwin Ag. Coll. Environmental Horticulture 139 Environ. Hort. Tifton, GA 31793 (229)391-4801 akowalewski@abac.edu WESTERN CANADA TURFGRASS ASSOCIATION 37