(Microclover or strawberry clover) with some of the most consistent performance, either mixed with improved tall fescue cultivars (DLFPS TFAM or DLFPS TFAStC), or chewings and strong creeping red fescue (DLFPS ChCrM). Possibly, the clovers’ nitrogen-fixing ability added density and survivability to the turf stands. Te tall fescue blend DLFPS TF-A and hard fescue MNHD-15 were also consistently good in 2020, along with Vitality Double, a 90 percent tall fescue/10 percent Ky. bluegrass mixture, and Vitality Low Maintenance Mixture. Yaak, the western yarrow entry that is interesting
as it is not a grass, nor a legume, was initially a good performer, but has declined the last three years. Yaak was still a top entry at Logan, UT, and performed reasonably well at Mead, NE, W. Lafayette, IN, St. Paul, MN, and Raleigh, NC. Yaak’s performance at Blacksburg, VA, and Corvallis, OR, has declined however since 2019. Yaak performance may have suffered from the fact that it is a ‘non-traditional’ lawn species and therefore its appearance is quite different from grasses, which may hurt its quality ratings. Terefore, Yaak may still have a place as a lawn species or ground cover where low maintenance and native plants are requested. Percent living ground cover ratings, averaged
over the five years by season showed interestingly, Yaak with the highest spring and summer cover percentage, tied with Southern Mixture (70 percent tall fescue, 10 percent Kentucky bluegrass, 10 percent perennial ryegrass and 10 percent chewings fescue) in spring ratings and just above Ky- 31 E+ tall fescue in summer ratings. Fall ground cover ratings had several tall fescue mixtures, led by DLFPS-TFAM at the top. Ground cover under low input is an important factor in weed suppression and overall quality. Percent weed cover ratings in the different seasons also reflected those high ground cover ratings as several tall fescue dominated mixtures also contained the lowest weed percentages. Overall, the five-year trial yielded some interesting
results, both consistent with past research and in some cases, surprising and promising. For instance, two mixtures with small percentages of clover, DLFPS TFAStC (97 percent tall fescue, 3 percent strawberry clover) and DLFPS TFAM (97 percent tall fescue, 3 percent Microclover) finished in the top 25 percent of turfgrass quality ratings at 75 and 50 percent of all locations, respectively. It is presumed that the nitrogen-fixing capability of the clover provides much needed nutrients to the turf. Not surprisingly, tall fescue entries such as Vitality Double, a 90/10 tall fescue/Kentucky bluegrass mixture performed well overall (finished in top 25 percent of entries in 58.3 percent of all locations), along with Bullseye tall fescue, a standard entry in the trial (top 25 percent of all entries at 50 percent of all locations). And a hard fescue, Chewings fescue mixture, Vitality Low also finished in the top 25 percent of all entries at 50 percent of all locations.
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NTEP’s first management-based trial on low input started in 2015. Tis cool-season grass low input trial in Michigan is shown in June of 2020. Photo by Geoff Rinehart
Cool-Season Water Use With the need to reduce turfgrass water use, the
United States Golf Association (USGA) is partnering with NTEP to evaluate both cool- and warm-season grasses for water efficiency and performance under lower water use. Te USGA has paid to install rain exclusion shelters at ten sites, five in the northern or transition zones (to evaluate cool-season grasses) and five shelters in the southern U.S. to evaluate warm-season grass water use and drought tolerance. Within these shelters, cooperators restrict irrigation for a period of 100 days on cool-season grasses, or 120-150 days for warm-season grasses. Tese ‘drought seasons’ under the shelters are part of Approach 1, which is a measurement of the amount of water needed to maintain a prescribed level of green during that period. Ten trial locations in the drier western U.S.
states (five each for cool-season and warm-season grasses) manage under Approach 2, which utilizes three evapotranspiration replacement rates (ETo
cool-season grasses, or 30, 45, or 60 percent ETo ). In Approach
2 locations, researchers replace either 40, 60 or 80 percent of ETo
(as determined by local weather station data) for for warm-
season grasses. Tis scenario is more typical of irrigation patterns in the western U.S. with 25 inches (63.5 cm) or less of annual rainfall. Approach 2 data indicates the reduced irrigation level each entry will survive, and at what level each entry will deliver acceptable turfgrass quality. Terefore, the two approaches address the needs
across the U.S., from the humid, eastern U.S. with 30-plus inches (76.2 cm) of annual rainfall but with occasional
TPI Turf News July/August 2022
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