Te cost to run each trial location is high, and only a portion of that is covered by USGA’s donation ($250,000). Terefore, we sincerely appreciate the support received from Te Lawn Institute (TLI) for the initiation of this trial. Without your support, this trial would not be conducted.
WARM-SEASON TRIAL
Due to slow establishment of some entries, data collection did not initiate until 2020. Data was collected at eight sites in both 2020 and 2021. Data from 2020 is available at
https://www.ntep.org/wsw.htm, with 2021 data available later this summer.
APPROACH 1
Rain exclusion shelter sites (Approach 1) rewatered plots when percent green cover reached 65 percent. Rain exclusion shelters are used to simulate 120-to-150-day drought periods in higher rainfall regions. Under the rain exclusion shelters, we measure the amount of water needed to maintain 65 percent green cover, rate turfgrass quality, as well as evaluate recovery from drought when irrigation is resumed. Irrigation amounts needed to maintain 65 percent green cover varied considerably among entries, and in some cases was more than double the best entry.
Due to facility and staff changes, two sites did not submit 2021 data. Te eight remaining sites collected and submitted 2021 data, allowing us to make inferences about second-year performance of this trial. Approach 1 sites (Mississippi State, MS; Griffin, GA; Jay, FL; Stillwater, OK) collected data on percent green cover, carefully watered plots with less than 65 percent green, recorded watering of each plot, and then presented total water applied per entry.
At the Approach 1 site in Stillwater, OK, the amount of water needed to maintain at least 65 percent green cover over the drought period varied from 0 – 67.7 mm (0 – 2.6 inches). Bermuda entries ‘FB 1628’, ‘TifTuf TM
’, and ‘Tifway’ did not
require any water to maintain 65 percent green cover. Joining those bermudas in the top statistical grouping were ‘Stellar’ zoysia (8.3 mm) (.327 in.), ‘Tahoma 31’ bermuda (8.3 mm) (.327 in.), and ‘FAES 1306’ zoysia (16.7 mm) (.657 in.). More water was required to maintain 65 percent green cover at the Approach 1 site in Mississippi State, MS. Te lowest water users were all either bermudagrasses: ‘Monaco’ (50.7 mm) (1.996 in.), ‘Tahoma 31’ (51.0 mm) (2.009 in.), ‘Rio’ (67.7 mm) (2.665 in.), ‘ASC 119’ (93.0 mm) (3.661 in.), and ‘ASC 118’ (135.7 mm) (5.343 in.), or buffalograsses: ‘Cody’ (118.3 mm) (4.657 in.)and ‘Prestige’ (135.7 mm) (5.343 in.), where the entry with the greatest water use needed 313.7 mm (12.3 inches).
TPI Turf News September/October 2022
At the Approach 1 sites in Griffin, GA, and Jay, FL, statistical significance was much smaller than at the Mississippi State and Stillwater locations. At the Griffin site, ‘TifTuf ’ required the least water (8.3 mm) (.327 in.) of all entries, followed by ‘Meyer’ zoysia (13.3 mm) (.524 in.) and ‘Tifway’ bermuda (25.3 mm) (.996 in.), two standard entries in this trial. However, at Griffin, no statistical differences were noted in water use among entries with total water used ranging from 8.3 – 71.0 mm (.327 – 2.795 in.) (LSD=77.8 mm) (3.063 in.).
At Jay, FL, bermudas ‘TifTuf ’, ‘FB 1628’, ‘OKC 1221’, ‘Rio’, and ‘Tahoma 31’, along with ‘Meyer’ zoysia did not require any water during the test period. Other entries requiring only one-half inch (12.7 mm) of water or less at Jay include ‘Monaco’ bermuda (4.3 mm) (.169 in.), ‘Stellar’ zoysia (8.3 mm) (.327 in.), and ‘FAES 1306’ zoysia (12.7 mm) (.5 in.). Tese entries and seven others are included the Jay, FL, top statistical group for water use in 2021.
APPROACH 2 Te drier climate ETo
-based sites evaluated performance
at three deficit irrigation levels for 120 to 150 day (17- 21 weeks) periods. Te exception is the Fort Lauderdale, FL, location which ran its evaluation for 33 weeks. Data recorded includes percent green cover over time, turfgrass quality, and recovery rate after complete replacement irrigation is initiated. Te ETo
-based locations allow
us to determine the minimum level of deficit irrigation appropriate for, and thus the water savings from, each
entry. It was determined that 60, 45 and 30 percent ETo replacement levels would be utilized for data collection.
Te Ft. Lauderdale site’s growing season is twelve months therefore their Approach 2 testing period is much longer than the others. As in 2020, the surprising result from 2021 was how well the entries performed even at the 30 percent ETo
all entries had scores at or above the minimum acceptable quality level of 6 under the 30 percent ETo
sixteen of the seventeen entries finished the season in the top statistical group. Tis is the second year we have seen the lowest ETo
replacement. On most turf quality rating dates, . As a result,
level producing adequate for turf quality in
south Florida. Te entries finishing with the highest overall turf quality include ‘TifTuf ’ (TQ=7.0), ‘FB 1628’ (6.9) and ‘Tifway’ (6.9).
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