The use of seeded bermudagrasses (Cynodon dactylon) is increasing as athletic field and golf course turf. Anecdotal evidence indicates probable and important differences in germination rates among cultivars when established in late spring or early summer. Germination studies were completed in May 2011 in the Turfgrass Science Laboratory at the University of Kentucky on 19 commercially available seeded bermudagrass cultivars. Evaluations for germination rate and total germination under varying temperature regimes representing 20-year average day/night temperatures for seeding times from 15 May to 1 Aug. were conducted to quantify any differences in germination characteristics among cultivars as affected by temperature. There were highly significant differences (P < 0.0001) among cultivars in germination rate and total germination when grown under 20-year average day/night temperatures. The cultivars Casino Royale and Riviera consistently represented the fastest/slowest to germinate and highest/lowest total seeds germinated across all temperature regimes, respectively. Significant differences (P < 0.0001) were also observed within cultivars for total germination across the temperature regimes tested. The average temperatures of 15 May and 1 Aug. represented slowest/fastest to germinate and lowest/highest total seeds germinated across all temperature regimes, respectively.
Common bermudagrass (Cynodon dactylon) and hybrid bermudagrass (Cynodon dactylon var. dactylon × C. transvaalensis) often are used for athletic fields as a result of their wear tolerance and recuperative ability. A wear tolerance study was conducted May 2007 through Nov. 2008 in Lexington, KY. Plots were managed as athletic turf and simulated traffic was applied during the Kentucky high school football seasons. The cultivars Quickstand, Tifway 419, Riviera, and Yukon grown in a sand-based medium were evaluated. Trinexapac-ethyl (TE) was applied at label rates and frequencies or left untreated. Overseeding treatments were perennial ryegrass (Lolium perenne) at 0, 546, and 1093 lb/acre pure live seed. Traffic treatments were applied with a Brinkman traffic simulator three times per week, once each Monday, Wednesday, and Friday, without regard to soil moisture status or weather for the periods 10 Sept. to 2 Nov. 2007 and 12 Sept. to 14 Nov. 2008. In both years of the study, the main effect of cultivar was significant (P < 0.05) in traffic tolerance (‘Tifway 419’ = ‘Riviera’ > ‘Quickstand’ = ‘Yukon’). Overseeding at the medium and high rates also provided significantly greater turf cover for the coarse-textured, more open cultivars (Quickstand and Yukon) over the fine-textured, more dense cultivars (Riviera and Tifway 419). Applications of TE did not significantly improve tolerance to simulated athletic traffic in either year of the study regardless of cultivar or overseeding treatment. Within the parameters of this study, data indicate that only cultivar has significant effects on tolerance to simulated traffic on a sand-based field. Overseeding treatments for the fine-textured, more dense cultivars and TE applications on sand-based field systems had no positive significant effects on tolerance to simulated traffic.
Zoysiagrass (Zoysia japonica Steud.) requires few inputs and provides high-quality turf in the transition zone, but is expensive to sprig or sod. Establishment by seed is less expensive than vegetative establishment, but little is known about renovation of existing turf to zoysiagrass using seed. Two experiments were performed to determine effects of herbicides and seeding rates on establishment of zoysiagrass in Indiana and Kentucky. In the first experiment, interseeding zoysiagrass into existing perennial ryegrass (Lolium perenne L.) without the use of glyphosate before seeding resulted in 2% zoysiagrass coverage 120 days after seeding (DAS). In plots receiving glyphosate before seeding, zoysiagrass coverage reached 100% by 120 DAS. In the second experiment, MSMA + dithiopyr applied 14 days after emergence (DAE) or MSMA applied at 14+28+42 DAE provided the best control of annual grassy weeds and the greatest amount of zoysiagrass establishment. Applying MSMA + dithiopyr 14 DAE provided 7% less zoysiagrass coverage compared to MSMA applied 14 DAE at one of the four locations. Increasing the seeding rate from 49 kg·ha-1 to 98 kg·ha-1 provided 3% to 11% more zoysiagrass coverage by the end of the growing season at 3 of 4 locations. Successful zoysiagrass establishment in the transition zone is most dependent on adequate control of existing turf using glyphosate before seeding and applications of MSMA at 14+28+42 DAE, but establishment is only marginally dependent on seeding rates greater than 49 kg·ha-1. Chemical names used: N-(phosphonomethyl) glycine (glyphosate); monosodium methanearsenate (MSMA); S,S-dimethyl 2-(difluoromethyl)-4-(2-methylpropyl)-6-(triflurormethyl)-3,5-pyridinedicarbothioate (dithiopyr).
Growers, nurseries, landscape contractors and installers, and those responsible for maintenance have observed a trend that trees are too deep within the root ball. This study addresses the relationship between planting depth and its effect on tree survival, root growth, root architecture, and caliper growth. The experiment was initiated to determine the effect of planting depth on nursery-grown trees. Three-year-old, 2.1–2.7 m, bare-root liners of Acer platanoides `Emerald Lustre', Fraxinus americana `Autumn Purple', Fraxinus pennsylvanica `Patmore', and Gleditsia triacanthos f. inermis `Shade Master' were planted in April 2004 in a completely randomized design with 20 replications per treatment per species. The trees were selected so that the distance between the graft union and the trunk flare was consistent. Trees were planted with the graft union 15.2 cm below the soil surface, or with the base of the graft union at the finished grade or with the trunk flare at the finished grade. The trees were grown in a nursery field setting with minimal supplemental watering. There were no differences in stem caliper growth at the end of two seasons in any of the four species. Root dry mass, stem elongation, and rooting structure were determined on a representative sample of trees while others were planted into the landscape for a long-term study of the effects of the original planting depth on landscape performance.
Use of seeded-bermudagrasses (Cynondon dactylon) is expanding rapidly, especially on high-use athletic fields. Previous work has defined significant differences in several parameters among cultivars. Experiments were conducted in Lexington, KY, in 2004 and 2005 to test the tolerance of the cultivars Riviera, Princess, Transcontinental, Savannah, Yukon, and the experimental line SWI 1012, with and without applications of trinexapac-ethyl to simulated athletic traffic. Plots were established in June of each year and managed as athletic field turf. Simulated traffic was applied using a Brinkman traffic simulator during high school football seasons in Kentucky at a level roughly equivalent to three games per week. Percentage of bermudagrass cover was visually rated weekly during the trafficking periods each year. Turfgrass quality was rated once before beginning traffic treatments each year. There were no consistent significant interactions (P > 0.05) among trinexapac-ethyl treatments and cultivars in either year of the study for either response variable. The main effect of cultivars was highly significant (P < 0.0001) for percentage of bermudagrass cover in both years of the study. Among cultivars, the ranges of percentage of bermudagrass cover at the end of the trafficking periods were 10.2% to 39.2% and 43.3% to 76.7% in 2004 and 2005, respectively. The main effects of trinexapac-ethyl on percentage of bermudagrass cover were significant (P < 0.0052) and more pronounced in 2004. Significant differences (P < 0.0200) were also recorded in 2005. Applications of trinexapac-ethyl resulted in increased tolerance to simulated traffic and improved turfgrass quality. Under the conditions of this study, data indicate that both cultivars and regular applications of trinexapac-ethyl have significant effects on overall turfgrass quality and the tolerance of these seeded bermudagrasses to simulated traffic.
Pecan [Carya illinoinensis (Wangenh.) C. Koch `Melrose'] and pear (Pyrus calleryana Decne. `Bradford') trees in the nursery grew more in containers designed to hold water in the lower portion. The water-holding reservoir was obtained either by placing 76-liter containers in a frame holding water to a depth of 6 cm or by using containers with drainage holes 6 cm from the bottom. Continuous waterlogging at the bottom of containers resulted in root pruning and root death in the lower portion of the containers, but roots grew well above the constantly wet zone. Fresh weight of plant tops and trunk diameters were greater after two growing seasons in the containers with water reservoirs compared to those grown in similar containers with no water reservoirs. Total root dry weight was unaffected.