1998 Iowa Turfgrass Research Report
1997 Kentucky Bluegrass Slow Release Fertilizer Study
Barbara R. Bingaman, Nick E. Christians, and Michael B. Faust
The purpose of this study was to evaluate the response of Kentucky bluegrass to various commercial fertilizers. The experimental plot was an established area of 'Park' Kentucky bluegrass at the Iowa State University Horticulture Station north of Ames, Iowa. The soil in this area was a Nicollet (fine-loamy, mixed, mesic Aquic Hapludoll) with 3.0% organic matter, a pH of 6.75, 4.5 ppm P, and 107 ppm K. Irrigation was used to supplement rainfall and maintain the turf in good growing condition.
The experiment was arranged in a randomized complete block design. Individual plots were 5 x 5 ft and three replications were conducted. All fertilizers were applied in a single application at 2 lb. N/1000 ft2 (Table 1). There were nine treatments including eight different fertilizers and an untreated control. Three experimental formulations (44-0-0), sulfur coated urea (39-0-0), Polyon (42-0-0). ESN (41-0-0), and Nutralene (40-0-0) were supplied by LESCO. In addition, IBDU (31-0-0) was included.
The fertilizers were applied on May 29, 1997. A pre-treatment survey of the plot showed that the bluegrass was uniform throughout. The materials were applied using 'shaker dispensers'. The materials were 'watered in' with the irrigation system. There was no substantial rainfall until mid-June so irrigation was used to maintain the plot.
Visual turf quality data were taken weekly beginning on June 4. Quality was assessed using a 9 to 1 scale: 9 = best, 6 = lowest acceptable, and 1 = worst turf quality. Subsequent data were taken weekly through September 26.
Data were analyzed using the Statistical Analysis System (SAS, version 6.10) and the Analysis of Variance (ANOVA) procedure. Means comparisons were made with Fisher's Least Significant Difference (LSD) test.
Differences in turf quality were detected among the treated and untreated plots from June 4 through June 25 (Table 1). On June 10, bluegrass treated with either sulfur coated urea or Nutralene had significantly better quality than the other treated and untreated turf. The quality of bluegrass treated with the other fertilizers was the same as the untreated turf. By June 18, the quality of all treated bluegrass, except turf treated with Exp. 1, was better than the untreated control. The quality of bluegrass fertilized with sulfur coated urea, ESN, and Nutralene was better than the other treated and untreated turf. On June 25, all fertilized turf had significantly better quality than the untreated turf. Sulfur coated urea, Exp. 3, ESN, Nutralene, Polyon, and IBDU produced the best quality. From July 2 through September 5, there were generally no quality differences among the fertilized bluegrass but all fertilized turf had better quality than the untreated control. After September 5, the fertilizer effects were no longer detected.
Table 1. Visual quality1 of Kentucky bluegrass treated for the 1997 Kentucky Bluegrass Slow Release Fertilizer Study.
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Untreated control |
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Exp. 1 (44-0-0) |
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Exp. 2 (44-0-0) |
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Exp. 3 (44-0-0) |
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Sulfur coated urea (39-0-0) |
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Polyon (42-0-0) |
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ESN (41-0-0) |
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IBDU (31-0-0) |
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Nutralene [MU (40-0-0)] |
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LSD0.05 |
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Visual quality was assessed using a 9 to 1 scale: 9 = best, 6 = lowest acceptable, and 1 = worst quality.
Fertilizer applications were made on May 29, 1997.
NS = means are not significantly
different at the 0.05 level.
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ISU Horticulture:Publications:1998 Turfgrass Report | College of Agriculture |