Applied Turfgrass Science最新文献

With golf course water, fertilizer, and pesticide restrictions on the rise and labor costs continuing to increase, golf course superintendents are looking for ways to reduce maintained Kentucky bluegrass (Poa pratensis L.) rough. The objective of this study was to (i) compare several methods for converting Kentucky bluegrass rough to no-mow, low-input grasses and (ii) determine the best turfgrass species that provides a playable and aesthetically pleasing turfgrass stand for this type of conversion. Five grass species and five conversion methods were evaluated at two locations in Minnesota. Data collected included visual stand quality, tendency for lodging, inflorescence counts, biomass production, Kentucky bluegrass regrowth, and broadleaf weed invasion. At Maple Grove, the fumigation treatment provided the highest visual stand quality ratings and the sod removal treatment at St. Paul provided the highest visual stand quality. Only sheep fescue (Festuca ovina L.) was able to provide acceptable visual stand quality by Year 2 and only at St. Paul. Chewing's fescue (F. rubra L. ssp. Commutata Gaudin) and strong creeping red fescue (F. rubra L.ssp. rubra) were best at resisting broadleaf weed invasion at both locations. Hard fescue (F. brevipila Tracey) was best at resisting lodging along with strong creeping red fescue in Year 2 at both locations.

Torpedograss is becoming an increasing weed problem in centipedegrass and St. Augustinegrass home lawns due to sod or soil contamination. Currently, the use of non-selective herbicides and/or renovation is the primary means of torpedograss control. Minimal research has examined cultural methods for torpedograss control; therefore, a study was conducted evaluating nitrogen (N) and mowing heights for the control of torpedograss in centipedegrass and St. Augustinegrass. St. Augustinegrass was fertilized at 0 kg N/ha/month, 50 kg N/ha/month, or 100 kg N/ha/month and maintained at heights of 5.0 cm, 7.6 cm, or 10.2 cm. Centipedegrass was fertilized at 0 kg N/ha/month, 12.5 kg N/ha/month, or 25 kg N/ha/month and mowed at 2.5 cm, 5.0 cm, or 7.6 cm. The highest mowing height resulted in the greatest torpedograss encroachment with each species when compared to the low and recommended heights. Nitrogen fertility had no effect on torpedograss encroachment in either species. All mowing height and N combinations exhibited patterns of increasing torpedograss encroachment over time. These data indicate the use of uncontaminated soils or applications of non-selective herbicides represent the best methods for controlling torpedograss in St. Augustinegrass and centipedegrass.

In order to utilize effluent or wastewater as irrigation on turfgrass sites it will require the identification of cool-season turfgrass cultivars with increased salinity tolerance. Evaluation of current cultivars and experimental selections for salinity tolerance is an important first step in making information available to turfgrass managers. An overhead irrigated field screening method was developed to closely mimic the challenges associated with irrigation of turf with saline water under summer stress conditions. A total 48 clones from each turfgrass cultivar were planted in a randomized complete block design with four replications (12 clones per replication) and were irrigated overhead with saltwater (EC =10 dS/m). This technique effectively identified differences in salinity tolerance, of Kentucky bluegrass, bentgrass, and perennial ryegrass cultivars and selections as measured by percent green ratings. The most salt tolerant cultivars included: Liberator, Eagleton, Diva, and Rhythm Kentucky bluegrasses; Declaration, Kingpin, and 007 creeping bentgrasses; and RKS, Gator 3, and MSH Comp perennial ryegrasses. Cultivars and selections exhibiting the least salinity tolerance were: RSP, A03-TB676, A03-84, and Julia Kentucky bluegrasses; EBM Comp and Tiger II colonial bentgrasses; SR7200 velvet bentgrass; and Fiesta III perennial ryegrass.

Bermudagrass (Cynodon spp. Rich.) and zoysiagrass (Zoysia spp. Willd.) are two of the most commonly used turfgrass species on golf course fairways and tees in the southern United States. However, there are few reports directly comparing commonly used cultivars of bermudagrass to commonly used cultivars of zoysiagrass. The objectives of this research were to quantify the clipping yield, percent ball exposed (ball lie), and to identify the scalping tendency for five bermudagrass and seven zoysiagrass cultivars grown in Fayetteville, AR. The cultivars generally producing the lowest clipping yields were ‘Patriot’ bermudagrass and ‘Meyer’ zoysiagrass, while ‘Tifway’ bermudagrass and ‘Palisades’ zoysiagrass generally had the highest clipping yields. On most collection dates, Cynodon spp. yielded more clippings than Zoysia spp. Patriot bermudagrass had the highest scalping tendency across the two years of this study. The cultivars Patriot, ‘Riviera,’ ‘Tifsport,’ and Tifway bermudagrass as well as Meyer and Diamond zoysiagrass had the best ball lie in unmown (five days after mowing) conditions, while Palisades zoysiagrass had the poorest ball lie in unmown conditions. Ball lie was similar for all cultivars immediately following mowing. These studies identified cultivars of bermudagrass and zoysiagrass that have improved clipping yields, scalping tendencies, and golf ball lie.

Golfers commonly remove turf and soil when swinging a golf club causing a divot in the turf. Divot recovery is an important factor that should be considered when selecting a species or cultivar for use on golf course tees or fairways. There are few reports directly comparing the divot recovery among bermudagrass (Cynodon spp. Rich.) and zoysiagrass (Zoysia spp. Willd.) cultivars. Therefore, the objective of this experiment was to quantify divot recovery of several bermudagrass and zoysiagrass cultivars in a combined field experiment. Divot recovery was evaluated on four collection dates for five cultivars of bermudagrass and seven cultivars of zoysiagrass. Cultivars generally with the fastest time to 50% recovery were ‘Princess 77’ and ‘Riviera’ bermudagrass and ‘Palisades’ zoysiagrass. Generally, the cultivars with the slowest time to 50% recovery were ‘Meyer’ and ‘Zenith’ zoysiagrass. Additionally, ‘Tifway’ bermudagrass had similar divot recovery times to ‘El Toro’ and Palisades zoysiagrass. These results demonstrate that differences and similarities exist among bermudagrass and zoysiagrass cultivars for divot recovery, and golf course superintendents can use this information to better select cultivars that could improve surface playing conditions.

Velvet bentgrass (Agrostis canina L.) has potential as a turf for low-input fairways and tees, but N fertility requirements during establishment are unknown. Our study compared the N fertility requirement of velvet bentgrass (VBG) cultivars to creeping bentgrass (Agrostis stolonifera L.) cultivars for fairway or tee establishment. Four N rates (0, 49, 146, and 293 kg/ha in six applications over 12 weeks) were tested on two cultivars of both bentgrass species [‘Memorial’ creeping bentgrass (CBG), ‘Penncross’ CBG, ‘SR7200’ VBG, and ‘Vesper’ VBG], on silt loams in Minnesota and Wisconsin during 2009. Treatments were arranged in a randomized block, split-plot design with four replications. Vesper established slower than Penncross through week 4 or 11, depending on location, after which all bentgrasses had ground cover approaching 100%. Increase in turf cover corresponded with increasing N rate for the first nine weeks after seeding (WAS). While all cultivars showed acceptable quality near trial end, CBG had better quality than Vesper in Wisconsin. In Minnesota, Memorial and SR7200 had better quality than Penncross and Vesper. The two greatest N rates provided similarly acceptable quality by about 8 WAS in both locations, while 0 kg N/ha never provided acceptable quality. All cultivars of VBG and CBG have similar N requirements during fairway or tee establishment.

Field experiments were conducted in 2009 and 2010 on two golf course practice putting greens in Spokane, WA (Esmeralda), and Hayden Lake, ID (Avondale), consisting of an approximate 50% blend of creeping bentgrass (Agrostis stolonifera L.) (CBG) and annual bluegrass (Poa annua L.) (ABG). Various regimes of trinexapac-ethyl (TE), flurprimidol (FL), paclobutrazol (PB), and TE + FL were investigated to determine which plant growth regulator (PGR) regime provided the greatest transition from ABG to CBG. Following PGR applications every two weeks over two growing seasons in the Northwest, PB at 0.28 kg/ha and FL at 0.22 and 0.28 kg/ha produced the greatest increase in CBG coverage, followed by TE + FL at 0.04 + 0.10 kg/ha. TE at 0.10 kg/ha consistently resulted in the least amount of CBG compared to other PGR treatments. While PGRs are an effective tool for superintendents to use for ABG suppression on putting greens, PGR selection, application rate, and application timing are important considerations for successful results.

Indaziflam is a new herbicide which potentially provides pre- and postemergence control of broadleaf and grass weeds. Two studies were conducted to evaluate indaziflam control of several weed species utilizing different application regimes. Single applications included indaziflam applied at 40 or 60 g ai/ha in October or November, and 20, 40, or 60 g ai/ha in March. Sequential applications included indaziflam applied at 40 followed by (fb) 40 g ai/ha in October and March, 60 fb 20 g ai/ha in October and March, 40 fb 40 g ai/ha in November and March, and 60 fb 20 g ai/ha in November and March. Prodiamine and oxadiazon were also applied as standard comparisons. Indaziflam applied at 60 g ai/ha in November provided the most consistent control across weed species. This treatment controlled annual bluegrass > 90% 20 weeks after treatment (WAT) and large crabgrass > 90% 29 WAT. All sequential indaziflam applications (except for the 40 fb 40 g ai/ha in November and March) controlled annual bluegrass > 90%. All rates and timings of indaziflam controlled lawn burweed at least 40% greater than industry standards. Indaziflam applied at 40 g ai/ha in October and March controlled cock's-comb kyllinga 80%. Indaziflam provided better weed control and longer residual activity than industry standards in some cases, however, weed control varied among species.

Bispyribac-sodium and sulfosulfuron are labeled for roughstalk bluegrass control in creeping bentgrass but comprehensive investigations are limited for long-term control. The objective of these field experiments was to investigate roughstalk bluegrass control with these herbicides on a creeping bentgrass fairway over three years. Bispyribac-sodium was applied twice at 37, 74, or 111 g a.i./ha or thrice at 37 or 74 g/ha. Sulfosulfuron was applied twice or thrice at 6.5 or 13 g a.i./ha or once at 26 g/ha. Creeping bentgrass chlorosis from herbicides was less than 20% by two to three weeks after applications while all treatments generally provided substantial reductions in roughstalk bluegrass cover by late July. However, roughstalk bluegrass regrowth was detected by October in all three years suggesting herbicide applications visually eliminated foliage but did not control the entire plant. Overall, bispyribac-sodium and sulfosulfuron effectively suppressed roughstalk bluegrass ground cover in summer months but regrowth during fall months prevented long-term successful control.