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Presented in partnership with Nufarm Turf & Specialty
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Rating turf quality
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University of Illinois faculty members Tom Voigt (left) and Bruce Branham survey the NTEP creeping bentgrass fairway trial at the university’s research site in May 2007. Photo by J. Krans |
According to Beard’s Turfgrass Encyclopedia (in the turf world, this is like saying, “According to Webster’s”), turfgrass quality is “the degree to which turf conforms to an agreed standard that is a composite of uniformity, shoot density, leaf texture, growth habit, smoothness and color.” Beard further defines visual turfgrass quality as “the subjective visual assessment of turfgrass quality; it usually is accomplished with two evaluators by ranking the turfed plots within an experiment from 1 to 9.”
Turf scientists routinely use a rating system of this type when they are evaluating the results of scientific research in turf plots. Despite Beard’s definition, in practice, the standards for visual turf evaluation are subjective in nature and, therefore, are not precisely defined.
In 2005 and 2006, the National Turfgrass Evaluation Program took a survey to identify the standards employed by NTEP-sponsored university turfgrass scientists to visually evaluate turf quality. The survey results and comments will be used to refine the current NTEP standards that scientists use when evaluating the quality of turf in experimental plots. NTEP believes that this refinement and improved standardization will reduce error in the outcomes of NTEP trials, which are used to compare the quality of turf cultivars.
Over a 17-month period, investigators visited 12 NTEP trial sites and asked seven questions of either the principal investigator (the person in charge of the research) or the principal rater (the person who made the visual turf evaluations) at each site. The questions covered protocols used in evaluations; components of turf quality considered; what score indicates minimally acceptable turf; the use of the top score, 9; methods for determining turf quality; and the importance of the NTEP trials to the school’s turf program.
Not all the scientists questioned could name Beard’s components of turf quality, but nine of the 12 listed uniformity and density as the most important components. The majority of the scientists also said that 6 is the score that represents minimally acceptable turf. Seven scientists said they never use the top score, 9; the remaining five said they use it conservatively.
The scientists used three methods to assign a turf quality score. One scientist rated quality on a comparative basis, assigning a 1 to the worst plot and 9 to the top plot. Four of the scientists evaluated turfgrasses based on optimal environmental and management conditions (OEM), no matter what the actual growing conditions and management are. Grass rated under OEM will often have a lower score because conditions are unlikely to be optimal at all times. The seven remaining scientists considered the current environment and management conditions of the turf (CEM) when evaluating turf quality. In theory, cultivars rated using the CEM standard would show a wider range of scores because the standard considers less-than-optimal conditions.
To comment on the survey or obtain more information, contact Kevin Morris, NTEP executive director, at kmorris@ntep.org. An article about this survey was published online in the Nov. 30 issue of Applied Turfgrass Science.
The annual industry awards given by the Industry Committee of the Crop Science Society of America’s turfgrass science division were recently announced. In the category of practical applications to turf management, oral competition, first place went to James P. Kerns; Debbie Morton of Purdue University won second place; and Patrick McCullough took third. In the pest management, posters competition category, Lane P. Tredway, North Carolina State University, won first place; Dustin F. Lewis, University of Tennessee, took second; and Daniel Earlywine of the University of Missouri took third place. Families of Fungicides for Turfgrass (January, 2008), has recently been updated and is available through Ohio State University. To obtain a copy by mail, contact Joseph Rimelspach at rimelspach.1@osu.edu. The publication can also be retrieved in pdf form by visiting the university’s Web site, http://buckeyeturf.osu.edu, and clicking on the “TurfNotes” link. |
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