A Survey of National Turfgrass Evaluation Program Sponsored University Scientists for Determining a Profile of Protocols and Standards used in the Visual Field Assessment of Turfgrasses

Determining a Profile of Protocols and Standards used in the Visual Field Assessment of Turfgrasses: A Survey of National Turfgrass Evaluation Program-Sponsored University Scientists

Jeffrey V. Krans, PhD, P.O. Box 723, Starkville, MS 39760; and Kevin Morris, Director, National Turfgrass Evaluation Program, 10300 Baltimore Ave., Beltsville Agricultural Research Center, West, Beltsville, MD 20705

Corresponding author: Jeffrey V. Krans. jkrans@centurytel.net

Abstract

The National Turfgrass Evaluation Program (NTEP) is a not-for-profit organization that facilitates the assessment of experimental and commercial turfgrasses for the turfgrass seed and sod industries in cooperation with university turfgrass scientists. The objective of this survey was to identify and compare common protocol and standards used by NTEP-sponsored university scientists to aid NTEP staff in writing a document entitled Protocol and Standards for the Visual Field Assessment of Turfgrasses. Twelve NTEP-sponsored university scientists were asked seven questions to ascertain the protocol and standards they used for the visual field assessment (VFA) of turfgrass quality. Collectively, scientists listed seven protocol categories and two or three options within each category. All scientists were aware of the definition of turfgrass quality, yet their ability to articulate all components of quality varied. The majority of scientists listed uniformity and density as the most important components of quality and one scientist each listed density and texture, density and color, or color as the most important. The majority of scientists used the 6 score as minimally acceptable quality and one scientist each listed 7, 5, or 4 as their minimally acceptable score. There were three methods used among scientist to determine a turfgrass quality score (1 to 9). Two methods used reference standards based on an idealized image and the other approach assigned a score based on a relative ranking without regard to a standard. All scientists stated that hosting NTEP trials was very important to their universities’ turfgrass research / teaching / extension programs.

Introduction

The visual field assessment (VFA) of turfgrass quality is a subjective ranking that varies with turfgrass species, cultural management, climate, season, and person conducting the assessment. Turfgrass quality was first defined by Beard (1), then recently published by Beard and Beard (2) as the degree to which a turf conforms to an agreed standard that is a composite of uniformity, shoot density, leaf texture, growth habit, smoothness, and color. The scale used to rank the VFA of turfgrass quality is widely accepted as 1 to 9, with 1.0 = poorest possible quality and 9.0 = best possible quality. Unfortunately, the protocol and standards used by scientists to rank turfgrass quality are not well defined in the turfgrass literature. The objective of this survey was to identify and compare common protocol and standards used by NTEP-sponsored university scientists to aid NTEP staff in writing a document entitled Protocol and Standards for the Visual Field Assessment of Turfgrasses. The to-be-written document is intended to normalize protocol and standards used by scientists, and thereby reduce the experimental error among scientists conducting these assessments.

The Survey

Twelve NTEP-sponsored university sites were visited over a 17 month period from March 2005 to August 2006 (Table 1).

Table 1. The NTEP-sponsored university sites visited.

NTEP-sponsored university sites visited	Date of visit
Louisiana State Univ. - Calhoun Research Station	March 2005
Kansas State Univ. - John Pair Horticulture Center	May 2005
Oklahoma State Univ. - Stillwater	May 2005
Univ. of Illinois - Chicago District Golf Assoc. Headquarters	August 2005
Pennsylvania State Univ. - State College	August 2005
Michigan State Univ. - East Lansing	August 2005
University of Georgia - Griffin	September 2005
Mississippi State Univ. - Mississippi State	September 2005
Univ. of Arizona - Heritage Highlands Golf & Country Club	March 2006
Texas A&M Univ. - Traditions Golf Course	March 2006
Cornell Univ. - Ithaca	August 2006
Colorado State Univ. - Fort Collins	September 2006

Scientist(s) representing each university were interviewed using seven questions to obtain a profile of the protocol and standards they used in the VFAs of turfgrasses. The scientists conducting the VFAs were either the principal investigator (PI), i.e., faculty member responsible for the NTEP contractual obligation, or the principal rater (PR), i.e., a research technician or associate responsible to the PI. The responses from each scientist were recorded and then later categorized according to content. The interview questions were:

• What protocol do you use when conducting VFAs?

• What components of turfgrass quality do you consider when conducting VFAs?

• What component(s) of turfgrass quality do you consider to be most important when conducting VFAs?

• What VFA scores of turfgrass quality do you assign as minimally acceptable?

• Do you use the 9 score when conducting VFAs for turfgrass quality?

• What method do you use to determine the turfgrass quality score?

• What is the importance of NTEP trial(s) to your University turfgrass research/teaching/extension programs

These questions were asked in a random order and, in some cases, follow-up questions were asked to obtain a complete understanding of the scientists’ answers. These interviews were not an NTEP undertaking to grade the PI or PR interviewed. The findings reported herein simply represent a profile of protocol and standards used for the VFAs of turfgrasses as well as the degree of diversity of responses. This report will aid NTEP staff in writing a document entitled Protocol and Standards for the Visual Field Assessment of Turfgrasses. NTEP anticipates that the publication and distribution of this report will stimulate discussion on this subject, and NTEP welcomes comments and suggestions from turfgrass scientists interested in this to-be-written document.

Survey Results and Interpretation

The use of defined protocols and standards are critical in collecting repeatable and consistent scientific measurements. The scientists interviewed consisted of seven PIs and five PRs. The collection of responses from question 1 (i.e., protocols used when conducting VFAs) are listed in Table 2. As a whole, scientists listed seven protocol categories and two or three options within each category. The ability of scientists to articulate protocol varied among scientists. Six scientists listed four or more protocol categories, whereas an equal number of scientists listed three or less categories (Table 3). Within each protocol category, the possible options and applications of these options varied among scientists. As an example, among those who listed orientation to the sun as a protocol category, some preferred facing the sun while others preferred standing with their backs to the sun.

Table 2. A collective list of protocol categories and options given by the twelve interviewed scientists when asked the question "What protocol do you use when conducting VFAs of turfgrasses."

Protocol catagories	Options listed within catagories
Time of day	Morning, afternoon, or midday
Sky condition	Overcast, partly cloudy, or full sun
Orientation to the sun	Person’s view is face-to-the-sun or back-to-the-sun
Length of lapsed time (h) post-mowing prior to VFA	Lapsed time ranged from 0 to 24 hours
Person’s view relative to the direction of mowing	Person’s view is "in-line" to direction of mowing or perpendicular to direction of mowing
Maintenance of plot identity	Plot corners are marked with paint or solid marker or individual plot boundaries are outlined with string or paint
Establishment of score range (1-9) prior to VFAs	One or more key reference plots are scored and marked prior to conducting VFA.

A comprehensive understanding of turfgrass quality and the components of quality are important prerequisites to conducting VFAs of turfgrasses. Questions two and three addressed the definition and importance of the components of turfgrass quality. All scientists were aware of the definition of turfgrass quality, yet the ability of scientist to articulate all components of turfgrass quality as initially defined by Beard (1) varied (Table 3). Nine scientists listed four or more quality components, whereas three listed three or less components. The components of quality considered most important was relatively consistent with nine scientists listing uniformity and density as the most important and one scientist each listed density and texture, density and color, or color as the most important.

The ranking score assigned by scientists to plots having minimally acceptable quality ranged from 7 to 4 (Question 4). The majority of scientists use the 6 score as minimally acceptable and one scientist each listed 7, 5, or 4 as their minimally acceptable score.

Question five addressed the use of the 9 score in the 1 to 9 scale. Seven scientists reserved or did not use the 9 score. The most common reasons for not using the 9 score were "9 represents perfect turfgrass quality and no turfgrass is perfect" or "new turfgrasses will be developed in the future having greater quality and the 9 score is reserved for those yet-to-be developed turfgrasses." Five scientists used the 9 score, but most of these individuals added that they were conservative in its use.

Question six addressed the method used by scientists to assign a turfgrass quality score (1 to 9). Three methods were articulated by scientists (Table 3). Two methods used a reference standard and the other used a relative ranking without regard to a standard. The use of a reference standard reference assumes that the scientist collecting VFAs has had prior experience in assessing turfgrasses. The reference standard approach was split along two schemes based on environment and management. The first method is based on an idealized turfgrass reference standard grown under an optimal environment and management regime (OEM). The OEM scenario suggests an idealized turfgrass image or standard of the best possible turfgrass quality regardless of the time of year or management regime. The other method is based on an idealized turfgrass reference standard grown under an environment and management regime that may or may not be optimal because the scientist takes in to account the current environment and management (CEM) of the turfgrass under assessment. An example of the difference in VFAs scores using the two reference standards (OEM or CEM) are illustrated for bermudagrass growing in the early spring season. Turfgrass quality of bermudagrass in the early spring is low because the grass is recovering from winter injury and temperatures are not optimal (less than 80 to 95°F) for its best possible quality. If the scientist conducting VFAs at this time of year uses the first reference standard (OEM), the VFAs will be in the low range of the 1 to 9 scale because the reference standard is optimized and the grass is growing at a suboptimal environment. However, if the scientist conducting VFAs of bermudagrass in the early spring uses CEM to formulate their idealized reference, then the VFAs scores would theoretically be distributed throughout the full range of the 1 to 9 scale because their reference standard takes into account the suboptimal environment. Four of the twelve scientists used the OEM idealized standard and seven used the CEM idealized standard. One scientist interviewed did not use a reference standard, but each entry was compared to one another and scored respectively using the 1 to 9 scale.

Question seven addressed the importance of NTEP trials to the host universities. All scientists stated that NTEP trials are very important to their universities’ turfgrass research/teaching/extension programs. The universal response from scientists is paraphrased as "NTEP trials provide first-hand access, appraisal, and knowledge of commercial and experimental turfgrasses that we (scientist) shared with our constituents."

Table 3. Interview questions asked and a summary of the responses from the twelve scientists interviewed.

Interview questions	Summary of responses	No. of responses
1. What protocols do you use when conducting VFAs? (See Table 4 for the collective list of protocols)	Listed 4 or more	6
	Listed 3 or less	6
2. What components of turfgrass quality do you consider when conducting VFAs? [See (2) for complete list]	Listed more than 3 components	9
	Listed less than 3 components	3
3. What component(s) of turfgrass quality do you consider to be most important when conducting VFAs?	Uniformity and density	9
	Density and texture	1
	Color and texture	1
	Color	1
4. What VFA score of turfgrass quality do you assign as minimally acceptable?	7 score	1
	6 score	9
	5 score	1
	4 score	1
5. Do you use the 9 score when conducting VFAs for turfgrass quality?	No, the 9 value is reserved	7
	Yes, the 9 value is used as needed	5
6. What method do you use to determine the turfgrass quality score?	Reference standard based on optimal environment and management (OEM) resulting in the best possible turfgrass quality.	4
	Reference standard based on current environment and management (CEM) that may or may not result in the best possible turfgrass quality.	7
	Each entry is compared to one another and scored respectively using on the 1 to 9 scale (no reference standard is used)	1
7. What is the importance of NTEP trial(s) to your University research/ teaching/ extension programs?	Very important	12
	Somewhat important	0
	Not important	0

Conclusions

Twelve NTEP-sponsored university scientists were asked seven questions to ascertain the protocol and standards they used when conducting the VFA of turfgrasses. All scientists were aware of the definition of turfgrass quality and the majority of scientist listed uniformity and density as most important and the 6 score as minimally acceptable. Although the majority of scientists responded similarly to most questions, all protocol and standards should be normalized among scientist engaged in the VFA of turfgrasses. All scientists stated that hosting NTEP trials was "very important" to their universities’ turfgrass research/ teaching/ extension programs. This high rating of importance should be a strong motivation for turfgrass scientists to adopt uniform protocol and standards. NTEP welcomes all persons interested in commenting on this report or the VFA of turfgrasses by contacting Kevin Morris (KMorris@NTEP.org). NTEP anticipates that a written document outlining the Protocol and Standards for the Visual Field Assessment of Turfgrasses will be drafted in 2008.

Acknowledgments

The authors express their appreciation and gratitude to all the financial sponsors and supporters of NTEP’s mission to provide unbiased and accurate measures of turfgrass performance and evaluation. The authors also express their appreciation to the NTEP Policy Committee members for their help and guidance in the review of this report.

Literature Cited

1. Beard, J. B. 1973. Turfgrass science and culture. Prentice Hall, Englewood Cliffs, NJ.

2. Beard, J. B., and Beard, H. J. 2005. Beard’s turfgrass encyclopedia for golf courses, grounds, lawns, and sports fields. Michigan State Univ. Press, East Lansing, MI.