Water requirements for `Meyer' zoysiagrass (Zoysia japonica Steud., hereafter referred to as zoysia), `Midlawn' bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy, hereafter referred to as bermuda], `Falcon II' tall fescue (Festuca arundinacea Schreb.) and `Brilliant' kentucky bluegrass (Poa pratensis L., hereafter referred to as bluegrass) were evaluated under a mobile rainout shelter at deficit irrigation levels of 20% to 100% of actual evapotranspiration (ETa), applied twice weekly, between June and September 2001 and 2002. Soil was a river-deposited silt loam (fine, montmorillonitic, mesic Aquic Arquidolls). Minimum annual irrigation amounts required to maintain quality ranged from 244 mm for bermuda to 552 mm for bluegrass. Turfgrass species and respective irrigation levels (% of ETa) at which season-long acceptable turf quality was maintained in each year were bluegrass, 100% (evaluated 2001 only); tall fescue, 60% in 2001 and 80% in 2002; bermuda, 60% in both years; and zoysia, 80% in both years. A landscape manager who could tolerate one week of less-than-acceptable quality could have irrigated tall fescue at 40% ETa (224 mm) in 2001 and 60% ETa (359 mm) in 2002. Likewise, bermuda exhibited unacceptable quality on only one September rating date when irrigated at 40% ETa (163 mm) in 2001. Bermuda was able to tolerate a lower leaf relative water content (LRWC) and higher level of leaf electrolyte leakage (EL) compared to other grasses before quality declined to an unacceptable level.
Jinmin Fu, Jack Fry, and Bingru Huang
E.H. Ervin, C.H. Ok, B.S. Fresenburg, and J.H. Dunn
'Meyer' zoysiagrass (Zoysia japonica Steud.) is a popular turfgrass species for transition zone golf course fairways and tees because it is generally winter hardy while providing an excellent playing surface with minimal chemical and irrigation inputs. However, its functionality declines readily on many of the shaded areas on these courses. Reduced irradiance causes excessive shoot elongation, reduced tillering, and weak plants that are poorly suited to tolerate or recover from traffic and divoting. Trinexapac-ethyl (TE) effectively reduces gibberellic acid (GA) biosynthesis and subsequent shoot cell elongation. The objective of this study was to determine if monthly applications of TE would reduce shoot elongation of 'Meyer' zoysiagrass and improve stand persistence under two levels of shade. Shade structures were constructed in the field that continuously restricted 77% and 89% irradiance. A mature stand of 'Meyer' was treated with all combinations of three levels of shade (0%, 77%, and 89%) and three levels of monthly TE application [0, 48 g·ha-1 a.i. (0.5×), and 96 g·ha-1 a.i. (1×)] in 1998 and 1999. In full sun, the 0.5×-rate reduced clipping production by 17% to 20% over a four-week period and the 1×-rate by 30% to 37%. Monthly application of TE at the 1×-rate increased 'Meyer' tiller density in full sun and under 77% shade. Both rates of TE consistently reduced shoot growth under shade relative to the shaded control. Only the monthly applications at the 1×-rate consistently delayed loss of quality under 77% shade. The zoysiagrass persisted very poorly under 89% shade whether treated or not with TE and plots were mostly dead at the end of the experiment. Our results indicate TE can be an effective management practice to increase 'Meyer' zoysiagrass persistence in shaded environments. Chemical name used: 4-cyclopropyl-α-hydroxy-methylene-3,5-dioxocyclohexanecarboxylic acid ethyl ester (trinexapac-ethyl)
M.J. Carroll, P.H. Dernoeden, and J.M. Krouse
Sprigs of `Meyer' zoysiagrass (Zoysia japonica Steud.) were treated with urea nitrogen, a biostimulator, and one of three preemergence herbicides or one of two postemergence herbicides to hasten establishment in two field studies. Monthly application of N at 48 kg·ha–1 during the growing season had no influence on sprig establishment the first year, but slightly increased (+5%) zoysiagrass cover the second year. Presoaking sprigs in a solution containing (mg·L–1) 173 auxin and 81 cytokinin, and iron at 1.25 g·L–1 before broadcasting of sprigs, and biweekly sprays (g·ha–1) of 53 auxin and 24 cytokinin, and iron at 0.2 g·L–1 or (g·ha–1) 68 auxin and 36 cytokinin, and iron at 1.45 g·L–1 after broadcasting sprigs had no effect on zoysiagrass cover or rooting. Preemergence and postemergence herbicide use generally enhanced zoysiagrass cover by reducing smooth crabgrass competition [Digitaria ischaemum (Schreb. ex Schweig) Schreb. ex Muhl]. Oxadiazon enhanced zoysiagrass coverage more than dithiopyr, pendimethalin, quinclorac, or fenoxaprop. Oxadiazon and dithiopyr provided similar levels of crabgrass control, but dithiopyr reduced `Meyer' zoysiagrass midsummer root growth. Chemical names used: 3,5,-pyridinedicarbothioic acid, 2-[difluromethyl]-4-[2-methyl-propyl]-6-(trifluoromethyl)-S,S-dimethyl ester (dithiopyr); [±]-ethyl 2-[4-[(6-chloro-2-benzoxazolyl)oxy]phenoxy] propanoate (fenoxaprop); 3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2-(3H)-one (oxadiazon); N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine (pendimethalin); 3,7-dichloro-8-quin-olinecarboxylic acid (quinclorac).
Ross Braun, Jack Fry, Megan Kennelly, Dale Bremer, and Jason Griffin
Zoysiagrass (Zoysia sp.) is a warm-season turfgrass that requires less water and fewer cultural inputs than cool-season grasses, but its widespread use by homeowners in the transition zone may be limited because of its extended duration of brown color during dormancy. Turf colorants are an option for improving zoysiagrass winter color. Our objective was to quantify the impact of colorants applied in autumn at three application volumes on persistence of green color on lawn-height ‘Chisholm’ zoysiagrass (Zoysia japonica). The commercial colorants Green Lawnger, Endurant, and Wintergreen Plus were applied in Oct. 2013 in Manhattan, KS, and Haysville, KS, in solutions with water at 80, 160, or 240 gal/acre at a 1:6 dilution (colorant:water) and evaluated through late 2013 and Spring 2014. Tall fescue (Festuca arundinacea), a cool-season turfgrass commonly used in home lawns in the transition zone, was included for comparison. Persistence of green color increased with application volume, but differences among colorants were limited. Colorants provided acceptable color (i.e., a visual rating ≥6 on a 1 to 9 scale) for 55 to 69 days at 80 gal/acre, 69 to 118 days at 160 gal/acre, and 118 to 167 days at 240 gal/acre. Compared with tall fescue, colorant-treated zoysiagrass had significantly higher color ratings for 98 to 112 days at 80 gal/acre, 112 to 154 days at 160 gal/acre, and 138 to 154 days at 240 gal/acre. Colorants increased turfgrass canopy temperature by up to 12.1 °F, but did not accelerate spring green-up. Duration of acceptable color on ‘Chisholm’ zoysiagrass lawns can be enhanced by increasing colorant application volume.
Ross C. Braun, Jack D. Fry, Megan M. Kennelly, Dale J. Bremer, and Jason J. Griffin
In the transitional climates, warm-season turfgrasses are more heat and drought resistant and require fewer pesticide and fertilizer inputs than cool-season turfgrasses, but an extended winter dormancy period in warm-season turfgrasses makes them less attractive. Our objective was to evaluate color intensity and persistence of colorants applied at two volumes, once or sequentially, on buffalograss (Buchloe dactyloides) maintained at 2.5 inches and zoysiagrass (Zoysia japonica) maintained at 0.5 inch. Field studies were conducted in Manhattan, KS, and Haysville, KS, from Oct. 2013 to May 2014 on dormant ‘Sharpshooter’ and ‘Cody’ buffalograss and ‘Meyer’ zoysiagrass. The colorants Green Lawnger, Endurant, and Wintergreen Plus were applied at 100 or 160 gal/acre in autumn (single application) or autumn plus midwinter (sequential application). Every 2 weeks, visual turf color was rated on a 1 to 9 scale (9 = best) with ratings based on the intensity of the color, not the color (hue) of green. Few differences in color persistence occurred among colorants, but color persisted longer at the higher spray volume. In general, buffalograss receiving a single autumn colorant application had acceptable color (i.e., a visual rating ≥6) for 55–70 days at 100 gal/acre or 55–88 days at 160 gal/acre. Zoysiagrass receiving a single autumn colorant application had acceptable color for 56–97 days at 100 gal/acre or 97–101 days at 160 gal/acre. Across all sites, a sequential midwinter application applied at 160 gal/acre on buffalograss and both application volumes on zoysiagrass provided acceptable green turf color from that point until spring green-up. Most buffalograss plots receiving the sequential midwinter application at 100 gal/acre had acceptable color from that point until spring green-up. Winter color of buffalograss and zoysiagrass can be enhanced by colorant application, and a longer period of acceptable color can be achieved by applying at a higher volume or by including a sequential midwinter treatment.
K.L. Hensler, B.S. Baldwin, and J.M. Goatley Jr.
A truly soilless turfgrass sod may be produced on kenaf-based (Hibiscus cannabinus L.) fiber mat that offers the integrity of field-cut sod without the use of mineral soil growing medium. This research was conducted to determine the feasibility of producing warm-season turfgrass sod on such a biodegradable organic mat. Seeded turfgrass plots contained 4.9 lb/1000 ft2 (24 g.m−2) of pure live seed planted on a 66-lb/1000 ft2 (325-g.m−2) organic fiber mat carrier placed atop either 66- or 132-lb/1000 ft2 (325- or 650-g.m−2) organic fiber mats. In an experiment using vegetative material, stolons were applied at rates of 16.4 ft3/1000 ft2 (0.82 L.m−2) over 132- or 198-lb/1000 ft2 (650- or 975-g.m−2) organic fiber mats and covered with a rayon scrim. All plots were placed on 6-mil black plastic. Nitrogen was applied at 0.9 lb/1000 ft2 (4.4 g.m−2) weekly in addition to a monthly micronutrient application. Bermudagrass (Cynodon σππ.) had quicker establishment than other grasses in the study, with stolonized and seeded plots achieving ≈100% coverage by 9 weeks in 1995 and 6 weeks in 1996, respectively. By 15 weeks after planting in 1995, the plot coverage ratings for seeded centipedegrass [Eremochloa ophiuroides (Munro) Hack. `Common'] and all stolonized grass plots of centipedegrass, zoysiagrass (Zoysia japonica Steud. `Meyer'), and St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze `Raleigh'] were 91% or higher. The results were much less favorable in 1996 than 1995 due to a later planting date and an irrigation failure.
Aaron J. Patton, David W. Williams, and Zachary J. Reicher
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).
Jinghua Fan, George Hochmuth, Jason Kruse, and Jerry Sartain
Reclaimed water (RW) is increasingly viewed as a valuable resource for supplying irrigation water and nutrients for landscape plants growing in urban environments. A greenhouse experiment was conducted to determine if nitrogen (N) in RW contributes significantly to turfgrass plant nutrition and to measure N use efficiency and the effects of irrigation with RW on N leaching. The factorial experiment was replicated four times and conducted in a greenhouse on the University of Florida campus for 1 year using ‘Floratam’ st. augustinegrass (Stenotaphrum secundatum) and ‘Empire’ zoysiagrass (Zoysia japonica). Treatments included irrigation with tap water (control), irrigation with RW from University of Florida wastewater treatment facility, irrigation with RW with additional N supplied from ammonium nitrate to achieve 5, 9, and 13 mg·L−1 N solutions, and a dry prilled fertilizer treatment based on the recommended N application rate for turfgrass in northern Florida. The average total N and phosphorus (P) concentrations of RW, based on 1 year weekly monitoring were 3.31 mg·L−1 total N with 2.14 mg·L−1 nitrate-N and 0.46 mg·L−1 ammonium-N, and 2.00 mg·L−1 P composed of 1.92 mg·L−1 orthophosphate. Turfgrass growth responded positively (P < 0.05) to N concentration in the irrigation water. The concentration of N in the unamended university campus RW was not sufficient for optimal turfgrass growth. Grass quality and turfgrass clippings yield maximized when the total N concentration in the irrigation water was at least 5 mg·L−1. Turfgrass receiving dry synthetic N fertilizer resulted in greater growth and 2-fold greater N leaching than with the remaining treatments for both turf types. The highest N recovery percentage for both turf types was found when the N concentration in the solution was 5 mg·L−1.
Jinmin Fu, Jack Fry, and Bingru Huang
Understanding turfgrass physiological responses to deficit irrigation will help explain potential effects of this practice on turf quality and subsequent stresses. The objective of this study was to investigate the influence of deficit irrigation growth and physiology of ‘Falcon II’ tall fescue (Festuca arundinacea Schreb) and ‘Meyer’ zoysiagrass (Zoysia japonica Steud). Turf was subjected to deficit irrigation levels of 20%, 40%, 60%, 80%, and 100% of actual evapotranspiration (ET) from June to Sept. 2001 and 2002 in Manhattan, Kans. In an earlier study, minimum deficit irrigation levels required to maintain acceptable quality (MDIL) were determined. We compared growth and physiological parameters at these MDIL with turf irrigated at 100% ET. Tall fescue had a lower canopy vertical growth rate (30% lower), canopy net photosynthesis (Pn, 14% lower), and whole-plant respiration (Rw, 11% lower) in 1 of 2 years when irrigated at the MDIL compared with 100% ET; tiller number was not reduced at the MDIL. Water use efficiency (μmol CO2 per mmol H2O) in tall fescue increased by 15% at the MDIL relative to turf receiving 100% ET in 1 of 2 years. In zoysiagrass, the MDIL had no effect on any of the growth or physiological parameters measured. Reductions in canopy vertical growth rate at the MDIL in tall fescue during deficit irrigation would likely reduce mowing requirements. Across all deficit irrigation levels, Pn was more sensitive to deficit irrigation in both grasses than was Rw, which could potentially contribute to declines in canopy vertical growth rate, tiller number, and turf quality. Zoysiagrass exhibited higher water use efficiency than tall fescue, particularly at irrigation levels 60% or more ET.
Yiwei Jiang and Robert N. Carrow
Canopy reflectance has the potential to determine turfgrass shoot status under drought stress conditions. The objective of this study was to describe the relationship of turf quality and leaf firing versus narrow-band canopy spectral reflectance within 400 to 1100 nm for different turfgrass species and cultivars under drought stress. Sods of four bermudagrasses (Cynodon dactylon L. × C. transvaalensis), three seashore paspalums (Paspalum vaginatum Swartz), zoysiagrass (Zoysia japonica), and st. augustinegrass (Stenotaphrum secundatum), and three seeded tall fescues (Festuca arundinacea) were used. Turf quality decreased 12% to 27% and leaf firing increased 12% to 55% in 12 grasses in response to drought stress imposed over three dry-down cycles. The peak correlations occurred at 673 to 693 nm and 667 to 687 nm for turf quality and leaf firing in bermudagrasses, respectively. All three tall fescues had the strongest correlation at 671 nm for both turf quality and leaf firing. The highest correlations in the near-infrared at 750, 775, or 870 nm were found in three seashore paspalums, while at 687 to 693 nm in Zoysiagrass and st. augustinegrass. Although all grasses exhibited some correlations between canopy reflectance and turf quality or leaf firing, significant correlation coefficients (r) were only observed in five grasses. Multiple linear regression models based on selected wavelengths for turf quality and leaf firing were observed for 7 (turf quality) and 9 (leaf firing) grasses. Wavelengths in the photosynthetic region at 658 to 700 nm or/and near-infrared from 700 to 800 nm predominated in models of most grasses. Turf quality and leaf firing could be well predicted in tall fescue by using models, evidenced by a coefficient of determination (R 2) above 0.50. The results indicated that correlations of canopy reflectance versus turf quality and leaf firing varied with turfgrass species and cultivars, and the photosynthetic regions specifically from 664 to 687 nm were relatively important in determining turf quality and leaf firing in selected bermudagrass, tall fescue, zoysiagrass and st. augustinegrass under drought stress.