SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
Issue link: http://read.dmtmag.com/i/433388
www.stma.org December 2014 | SportsTurf 9 loam soil. Studies were conducted under two different irrigation levels which were intended to simulate various stages of municipal water restrictions. One study received a single (0.8") weekly irrigation and the other received no supplemental irrigation (rainfall only, with 8.6" of rain received over the November- May period). Overseeding was performed in early October with either perennial ryegrass (Futura blend, Pickseed, USA) or turf type annual ryegrass (Panterra SOS 400, Barenbrug USA) at a rate of 10 lbs. per 1000 sq. ft. Non-overseeded plots were either left untreated, or treated with a single early November application of turf colorant (Greenlawnger, Becker Underwood) just before dormancy (~50% green cover remaining in plots) at a rate of 7.5 gallons product per acre. Colorant was diluted to a ratio of 1 gallon Greenlawnger per 8 gallons water before application and applied using 8004VS flat fan nozzles. During the study, simulated traffic was applied to half of each plot using a Cady traffic unit at a rate of 4 passes per week, intended to simulate two football games between the hash marks from 40 yard line to 40 yard line. Overseeded plots were mowed to 1.25" weekly during the study with clippings returned. Monthly during the study, ratings were taken in plots. Data collected included turf quality and cover, percent wear, surface hardness, soil moisture, and spring bermudagrass transi- tion differences in plots. Comparative performanCe of perennial vs. turf-type annual ryegrass Of particular interest in this study was the comparative perfor- mance and quality of perennial ryegrass and turf-type annual ryegrass, especially under the context of limited irrigation and traffic stress. Our data indicate that the two offered similar levels of quality from December through April in both 1 day/week irrigation as well as un- irrigated studies. Under the 1 day/week irrigation, winter visual quality averaged 6.9 and 7.3 out of 9 (perennial and annual, respectively) in the absence of traffic (Figure 1). Under un-irrigated (rainfall only) condi- tions, perennial and annual ryegrass winter quality was also very similar (5.4 and 5.3 out of 9, respectively), just above minimally acceptable quality (Figure 2). It should be noted that while overall visual quality ratings were similar between the species, perennial ryegrass did exhibit somewhat darker green color compared to the annual ryegrass. However, slightly superior upright growth, density, and uniformity of the annual ryegrass offset this, contributing to its similarly high quality during the study. The two species also exhibited similar levels of traffic tolerance under the four passes per week traffic level. When averaged across the season in irrigated plots, traffic caused a similar (<10%) reduction in quality in both species (Figure 1). How the two would compare under more intensive traffic is also of interest, but could not be gained from this current study. Finally, in May ratings of percent bermudagrass transition, similar levels of bermudagrass were observed (~60%) in both annual and perennial ryegrass overseeded plots. performanCe of Colorant-treated bermudagrass We were also interested in evaluating the benefit and longevity of a single early November colorant application to bermudagrass. While colorant-treated plots held acceptable quality well into mid-January, ~8 to 10 weeks after treatment (Figure 3), mean seasonal quality of colorant-treated plots averaged 4.5 out of 9 in both irrigated and un-irrigated conditions, which was significantly better quality and appearance than dormant turf, but inferior quality to overseeded plots in both irrigation levels (Figures 1, 2). Because the colorant effects had noticeably faded by April, no differences in bermudagrass greenup between untreated and treated plots were observed in April or May ratings. Finally, colorant application mitigated the effects of traffic Figure 1. Effect of traffic on visual quality in 1 day/week irrigated plots during bermudagrass dormancy for the colorant and over- seeded treatments. Data have been averaged across the December through March period. Values ≥5 are considered acceptable quality. RIGHT: Figure 2. Visual quality of un-irrigated plots during bermudagrass dormancy for the colorant and overseeded treatments. Data have been averaged across the December through March period. Values ≥5 are considered acceptable quality. Figure 3. Visual turf quality of colorant-treated and untreated dormant bermuda- grass in un-irrigated plots during the winter and early spring. Values ≥5 are considered acceptable quality.