1998 Iowa Turfgrass Research Report

1998 Iowa Turfgrass Research Report

Athletic Field Turfgrass Response to Calcined Clay Topdressing

David D. Minner and Jeffrey J. Salmond

Calcined clay materials have been used to amend soils that are compacted by excessive traffic. Our objective was to evaluate calcined clay as a topdressing material and its effects on turfgrass growth. The study is being conducted on a local high school football/soccer practice field and the calcined clay materials are being compared with sand treatments.

A study was initiated in August 1996 to evaluate calcined clay (Turface^® MVP) as a topdressing material. The study was conducted on an irrigated practice field containing native clay loam soil. The 9000 sq.ft. experimental plot area was arranged between the hash marks and twenty-yard lines. Each individual plot measured 15 ft. by 50 ft. for a total of 12 plots. Treatments consisted of two topdressing materials, calcined clay or sand, with six replications. Six plots were topdressed with calcined clay (4500 total sq.ft.) and six plots were topdressed with sand (4500 total sq.ft.). Plots were core aerified with 3/4-inch tines at a 4-inch depth, materials (calcined clay or sand) topdressed, core aerified again, seeded with a Gridiron blend of three Kentucky bluegrass cultivars and two perennial ryegrass cultivars, and fertilized (Table 1). The sand was topdressed at the same depths as the calcined clay. Plots were arranged every 5 yards. Core plugs were not removed and the plugs and topdressing were mixed on the surface by separately dragging each plot.

The procedure for topdressing materials is presented in Table 1. To date, the calcined clay plots contain a rate of 1785 lbs/ 1000 sq.ft. or 1339 lbs per plot area. One-quarter inch of topdressed calcined clay on the individual plots is equivalent to a rate of 714 lbs/ 1000 sq.ft. The experimental plot layout is presented in Table 2.

Plots will be evaluated each month on turfgrass quality and percent turfgrass cover. The study will be continued through 1999.

Table 1. Renovation schedule for topdressed calcined clay.

Sept. 1, 1996	core aerify	Turface 1/4 in. (714 lbs/1000 sq. ft.)	core aerify	seed	fertilize
Nov. 1, 1996	core aerify	Turface 1/4 in. (714 lbs/1000 sq. ft.)	core aerify	seed	fertilize
April 1, 1996	core aerify	Turface 1/8 in. (357 lbs/1000 sq. ft.)	core aerify	seed	fertilize

Table 2. Experimental plot layout for topdressed calcined clay and sand between the hash marks and twenty-yard lines on a practice football field.

20 30 40 50 40 30 20

yard line

ISU Horticulture:Publications:1998 Turfgrass Report

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