1998 Iowa Turfgrass Research Report
Evaluating Turfgrass Species for Use Over Buried Steam Lines 1996-98
David D. Minner, Jeffrey J Salmond, John E. Jordan, and Barbara R. Bingaman
This two-year study was initiated in the summer of 1996 to evaluate the performance of various grass species planted in an area with elevated soil temperatures above a steam line. The 16-inch diameter steam line has 3.5 inches of 400š F insulation and is buried 3.5 ft below the surface. The 400š F steam temperature has produced summer soil temperatures of 120š F at the 12-inch depth. The performance of both warm and cool season grasses was monitored over a two-year period. Kentucky bluegrass, perennial ryegrass, tall fescue, and combinations of these species represent the cool season species. Three warm season species; zoysiagrass, bermudagrass, and buffalograss, were used alone and in combination with cool season species. A total of 18 different grass combinations were planted in the summer of 1996 from either seed or sod. In addition three cultivars, J-554, J-36, and J-37, were added in nonreplicated plots.
The design of this trial was a randomized complete block with three replications. The experiment was situated in a 320 x 10 ft area above a buried steam tunnel on the intramural recreational facility of the ISU campus. Individual plot size was 5 x 10 ft and three replications were included. The individual plots were placed perpendicular to the length of the steam line so that the middle of each plot was directly over the steam line and received higher temperatures than either the east or west section of each plot.
Turf establishment was assessed by rating visual quality, turf color, and percentage green cover. The initial ratings were taken on October 10, 1996. Additional data were taken in 1997 on April 3 and May 3 and in 1998 on March 25. Visual quality was assessed using a 10 to 1 scale: 10 = best quality, 6 = lowest acceptable quality, and 1 = worst quality (Table 1). Brown or dormant turf was considered a negative aspect of overall turf quality. Therefore, winter dormant warm season grasses received lower turf quality scores based primarily on poor turf color. Turf color was evaluated using a 9 to 1 scale: 9 = best color and 1 = worst color (Table 2). Percentage green turf cover represents the area per plot covered by green turf (Table 3).
Soil temperatures were taken in 1996, 1997, and 1998 directly over the steam line and in the center of each plot. Temperature was measured at the 2-, 6-, and 12-inch depths (Tables 4, 5, and 6).
Data were analyzed with the Statistical Analysis System version 6.10 (SAS Institute, 1989) using the Analysis of Variance (ANOVA) and General Linear Methods (GLM) procedures. Fisher's Least Significant Difference test (LSD) was used to compare means where appropriate.
Table 1. Visual turf quality of grass species established for the 1996-98 Steam Tunnel Turf Cultivar Study.
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1 |
Perennial ryegrass |
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2 |
Kentucky bluegrass |
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3 |
Tall fescue |
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4 |
Kentucky bluegrass + p. ryegrass |
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5 |
Tall fescue + K. bluegrass |
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6 |
Zoysiagrass |
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7 |
Zoysiagrass + tall fescue/K. bluegrass |
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8 |
Buffalograss |
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9 |
Buffalograss + K. bluegrass/p. ryegrass |
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10 |
Bermudagrass |
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11 |
Bermudagrass + K. bluegrass/p. ryegrass |
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12 |
Zoysiagrass |
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13 |
Bermudagrass |
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14 |
Buffalograss |
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15 |
Zoysiagrass + tall fescue/K. bluegrass |
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16 |
Bermudagrass +K bluegrass/p. ryegrass |
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17 |
Buffalograss + K. bluegrass/p. ryegrass |
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18 |
Tolf Bermudagrass |
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LSD0.05 |
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1Turf quality was assessed using a 10 to 1 scale: 10 = best, 6 = lowest acceptable, and 1 = worst quality.
2These grasses were not replicated, they were planted in Rep 2 only. Data from these treatments were not included in the analyses.
Table 2. Color of grass species established for the 1996-98 Steam Tunnel Turf Cultivar Study.
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Grass Type |
Started from sod |
Started from seed |
Oct 1996 |
April 1997 |
May 1997 |
March 1998 |
Mean |
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1 |
Perennial ryegrass |
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X |
9 |
7 |
8 |
7 |
8 |
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2 |
Kentucky bluegrass |
X |
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9 |
8 |
8 |
8 |
8 |
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3 |
Tall fescue |
X |
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-- |
-- |
-- |
-- |
-- |
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4 |
Kentucky bluegrass + p. ryegrass |
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X |
9 |
7 |
8 |
7 |
8 |
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5 |
Tall fescue + K. bluegrass |
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X |
9 |
8 |
7 |
7 |
8 |
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6 |
Zoysiagrass |
X |
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9 |
1 |
2 |
1 |
3 |
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7 |
Zoysiagrass + tall fescue/K. bluegrass |
X |
X |
9 |
1 |
2 |
1 |
3 |
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8 |
Buffalograss |
X |
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9 |
1 |
5 |
1 |
4 |
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9 |
Buffalograss + K. bluegrass/p. ryegrass |
X |
X |
9 |
1 |
5 |
1 |
4 |
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10 |
Bermudagrass |
X |
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9 |
1 |
5 |
1 |
4 |
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11 |
Bermudagrass + K. bluegrass/p. ryegrass |
X |
X |
9 |
1 |
5 |
1 |
4 |
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12 |
Zoysiagrass |
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X |
8 |
1 |
1 |
1 |
3 |
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13 |
Bermudagrass |
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X |
9 |
1 |
1 |
1 |
3 |
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14 |
Buffalograss |
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X |
8 |
2 |
3 |
1 |
3 |
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15 |
Zoysiagrass + tall fescue/K. bluegrass |
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X |
8 |
1 |
1 |
1 |
3 |
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16 |
Bermudagrass +K bluegrass/p. ryegrass |
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X |
9 |
2 |
1 |
1 |
3 |
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17 |
Buffalograss + K. bluegrass/p. ryegrass |
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X |
8 |
2 |
3 |
1 |
4 |
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18 |
Tolf Bermudagrass |
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X |
9 |
1 |
2 |
1 |
3 |
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LSD0.05 |
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0.2 |
1 |
1 |
1 |
0.4 |
1Turf color was assessed using a 10 to 1 scale: 10 = best, 6 = lowest acceptable, and 1 = worst color.
2These treatments were not replicated, they were in Rep 2 only. Data for these treatments were not included in the analyses.
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ISU Horticulture:Publications:1998 Turfgrass Report | College of Agriculture |