Nick E. Christians and Luke Dant
The objective of this study was to evaluate sod tensile strength and quality of turf treated with preemergence herbicides. The study was conducted at the Iowa State University Turf Research Facility on 'Glade' Kentucky bluegrass. Treatments included Barricade (Prodiamine) 4FL at 0.5, 0.75, and 1 lb a.i./acre and Barricade 65 WG at 1.0 lb a.i./acre.
The study was conducted as a randomized complete block. Each treatment was replicated four times with plots being 5 ft by 15 ft. All treatments were applied on April 26 using a carbon dioxide backpack sprayer with #8002 flat fan TeeJet nozzles at 30-40 psi and diluted to a total spray volume of 3 gal per 1000 sq. ft. The soil on the area is a Nicollett (fine-loamy, mixed, mesic Aquic Hapludoll) with 4.0 % organic matter, 11 ppm P, 90 ppm K, and a pH of 6.75.
Sod harvest dates were approximately 30, 60, 90 and 120 days after application of the herbicides. Sod was harvested from a subsection of each plot using an 18" sod cutter set at a cutting depth of 1/2-inch. The sod was then placed in a clamp that was attached to a hydraulic jack. A gauge placed in the hydraulic system recorded the pressure in pounds per square inch (psi) needed to break each piece of sod. Sod harvested from each plot was broken 4 times. One outlying data point was dropped and the remaining three were averaged. The mean of the three numbers were recorded as a single data point for that date and treatment. An analysis of variance was performed on the data using SAS (Statistical Analysis System).
The herbicide treatments had no effect on turf quality at any time during the study. There were no significant differences in sod tensile strength on any of the four testing dates (Table 1).
Table 1. Sod tensile strength study 2002. Data are lbs/in2 required to break 18 inch sod pieces.
| Rate | Sod Tensile Strength psi | |||||
|---|---|---|---|---|---|---|
| Material | lb a.i./A | 5/28 | 6/26 | 7/25 | 8/31 | |
| 1 | Untreated Control | NA | 430 | 400 | 330 | 279 |
| 2 | Barricade 4 FL | 0.5 | 408 | 411 | 318 | 234 |
| 3 | Barricade 4 FL | 0.75 | 413 | 433 | 300 | 216 |
| 4 | Barricade 4 FL | 1.0 | 348 | 416 | 306 | 216 |
| 5 | Barricade 65 WG | 1.0 | 404 | 464 | 284 | 214 |
| LSD 0.05 | NS | NS | NS | NS | ||
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ISU Turfgrass:2003 Turfgrass Report | College of Agriculture |
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