FEATURE
USING RESULTS
FROM THE
NATIONAL TURFGRASS EVALUATION PROGRAM ( NTEP )
By Dave Han, Ph.D. Auburn University and Alabama Extension
THE
National Turfgrass Evaluation Program (NTEP) is a fantastic source for information on newlyreleased and upcoming turfgrass varieties. Since 1983, NTEP has been evaluating turfgrass varieties and making data from those variety trials available for free to the public. A survey of turfgrass managers published in 2019 determined that 87% of the 306 respondents to the survey had heard of the NTEP program. At the same time, over half of the respondents (52%) said they visited the NTEP (www.ntep.org) website to look at trial results either never or less than once per year (Yue et al., 2019). Could NTEP be used more? I think so. I personally use their data many times per year, but along the way I have developed some tricks and tools to help me get the most out of what sometimes seems to be an overwhelming mountain of numbers. So let’s take a quick tour of NTEP, what it is and how it works, and how to find what you need from their data reports.
How NTEP works NTEP is a non-profit cooperative effort between the U.S. Department of Agriculture, state universities, and turfgrass industry groups. The variety trials that NTEP sponsors, cover the most commonly-used turfgrasses (both cool season and warm season, see Table 1) in the United States. Trials typically run for five years, and are called by the year they were established. For example, the 2013 National Bermudagrass Test was planted in 2013 and contains data from the 2013–2017 growing seasons. The currently-running bermudagrass trial is the 2019 National Bermudagrass Test, which was established in 2019.
TABLE 1. NTEP tests data are available for these species COOL SEASON
WARM SEASON
Creeping bentgrass (putting greens)
Bermudagrass
Creeping bentgrass (fairways/tees)
Buffalograss
Fineleaf fescues
Zoysiagrass
Kentucky bluegrass
St. Augustinegrass
Perennial ryegrass
Seashore paspalum
Tall fescue
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MTC TURF NEWS
Tests are established at many sites throughout the regions where a particular species will grow. Typically, there are around 10 – 15 sites, though this varies with each test. The sites are usually associated with research universities – for example, at our main research facility in Auburn, Auburn University has the current bermudagrass and zoysiagrass NTEP trials. We also had the just-finished 2016 St. Augustinegrass trail and established a bentgrass trial this fall. In the past, we have also run NTEP tests at outlying research units, such as a tall fescue trial at the Sand Mountain Research and Extension Center in northeastern Alabama. Occasionally, NTEP will place tests on-site, especially for tests on putting greens. NTEP also ran a perennial ryegrass overseed trial, with locations on golf course fairways. For on-site tests, the golf course maintains the tests day-to-day, and university researchers typically evaluate the tests the same way they do on-campus ones. Because NTEP places trials in as many places as it can where a species will grow, they are able to collect data from many different environments. This is good, but it can also trip up an end user. For example, the current bermudagrass NTEP has locations including Riverside, CA, Ft. Lauderdale FL, Wichita, KS, and West Lafayette, IN. While it is very helpful for a plant breeder at a university or a seed company to know how their new bermudagrass performs in environments as different as these, if you are a sod farmer, landscaper, sports field manager, or other end user, you probably are interested only in how the grass performs in your own environment. More on this later.
What are NTEP ratings? There is a lot of information available from NTEP tests, but the bread and butter is the visual quality rating. There have been attempts over the years to determine whether equipment such as handheld optical sensors can provide more consistent, better, or faster ratings, but a trained observer still functions as well as equipment and has the advantage of being cheaper and more universally available. Still, the fact that different people evaluate ratings at each site is important to remember when looking at the data. NTEP publishes guidelines on how to rate their tests on the web (https://ntep.org/pdf/ratings.pdf). Quality ratings are taken on a scale of 1 – 9, where 1 is the poorest possible rating (no turf at all) and 9 the best. A rating of 6 or above indicates acceptable turf quality. This means that a rating of “6” has a different meaning when evaluating a bentgrass putting green versus a tall fescue lawn. Quality ratings take into account the density, texture, color, and effects of pests or environmental stress on the turf. Often these individual factors are broken out and rated separately, too. Sometimes, a location will focus on a specific factor – for example, locations in arid environments often focus on rating drought or salinity tolerance. Sometimes, a particular site will put extra stress on a test – traffic being the main examples. Only some sites in any given test will do this. Finally, some sites may let disease or insect damage go to a certain point in order to see differences in varieties’ susceptibility – but not let plots die completely. Most sites control diseases and insects to ensure that the trial can run for the full five years.
