). Research is currently underway to determine the efficacy of mesotrione for broadleaf and grassy weed control in managed turfgrass systems. Mesotrione is not currently labeled for use on actively growing bermudagrass [ Cynodon dactylon (L.) Pers.] turf
Dean A. Kopsell, James T. Brosnan, Gregory R. Armel, and J. Scott McElroy
James T. Brosnan, Adam W. Thoms, Gregory K. Breeden, and John C. Sorochan
evaluate the traffic tolerance of ‘Riviera’ bermudagrass ( Cynodon dactylon L.) after treatment with various PGRs commercially marketed for use in turfgrass management. Materials and Methods Research site. A 2-year field study was conducted
James T. Brosnan, Dean A. Kopsell, Matthew T. Elmore, Gregory K. Breeden, and Gregory R. Armel
for weed control efficacy in turfgrass and ornamentals ( Armel et al., 2009 ; Brosnan et al., 2010 ). Mesotrione is currently registered for weed control in turf ( Anonymous, 2009b ) and has been shown to injure common bermudagrass [ Cynodon dactylon
Nikolaos Ntoulas, Panayiotis A. Nektarios, and Glykeria Gogoula
% Cynodon dactylon , 50% Festuca arundinacea , and 15% Poa pratensis ). The composted olive stone-amended substrate improved turf visual quality, color, shoot density, uniformity, and coverage. Alburquerque et al. (2007) in a controlled pot study
Margaret E. Wolf and Michael W. Smith
Leachates of living Cynodon dactylon (L.) Pers. and Amaranthus sp. were applied to Carya illinoinensis (Wangenh.) C. Koch. seedlings to compare effects on growth and elemental absorption. Water applied to the weed pot or control pot (no weeds present) leached through the pot and into a funnel with a tube attached, then directly into the corresponding pecan seedling pot. After 4 months of growth, pecan seedlings receiving weed leachates had less leaf area and were shorter than those watered through control pots. These results suggest that leachates from these two weed species inhibit pecan growth, independent of any competition effects.
J.M. Goatley Jr., V.L. Maddox, and K.L. Hensler
Bermudagrass turfs in the southern United States often receive late growing season applications of nitrogen (N) in order to sustain turfgrass color prior to dormancy, even though such applications might increase winterkill potential. Yearly research trials were initiated in the last week of Sept. 1989 to 1991 at Mississippi State Univ. to evaluate fall and spring color responses and rhizome levels of total nonstructural carbohydrates (TNC) of `Tiflawn' and Arizona (AZ) Common bermudagrass [Cynodon dactylon L. (Pers.)] treated with various N sources delivering N at 98 kg·ha-1 in a single application. The fertilizers were ammonium nitrate (AN), sulfur-coated urea (SCU), a natural organic (`Milorganite', NO), isobutylidene diurea (IBDU), ureaformaldehyde (UF), and methylene urea (MU). Color responses from N fertilization were most prominent in the fall except when there was an early frost event in Oct. 1990. The most rapid greening response and highest color ratings were consistently observed for the water-soluble AN. Of the slow-release sources, SCU, MU, and IBDU provided color responses as long as temperatures remained warm enough to promote bermudagrass growth. The NO source provided an unexpected, significant greening response in Oct. 1989 and 1991 on `Tiflawn', but not on AZ Common. The UF consistently provided the lowest color ratings. There were virtually no differences in TNC levels between N treatments for either grass. At no time was there any indication that N fertilization increased bermudagrass winterkill potential; to the contrary, the predominant responses were better fall and spring color than the nontreated control.
K.L. Hays, J.F. Barber, M.P. Kenna, and T.G. McCollum
This study was conducted to determine rooting characteristics, root carbohydrate content, and performance of 10 bermudagrass [Cynodon dactylon (L.) Pers.] genotypes exposed to drought. A greenhouse study was conducted twice to determine root distribution and carbohydrate content throughout the soil profile during simulated drought stress. Root distribution among genotypes and accumulation of total nonstructural carbohydrate within roots differed with depths. Root mass at 30, 60, 90, and 150 cm was significantly correlated with turf quality during drought stress (r = 0.72, 0.86, 0.80, and 0.81, respectively) only for one of the two tests. Root carbohydrate distribution was not significantly correlated with turf quality for the selected bermudagrass genotypes.
Michael W. Smith, Becky S. Cheary, and Becky L. Carroll
Newly planted pecan (Carya illinoinensis Wangenh. C. Koch cv. Kanza) trees were grown for 5 years in a bermudagrass [Cynodon dactylon (L.) Pers.] sod with vegetation-free circles 0, 0.91, 1.83, 3.66, or 7.32 m in diameter. Trees were irrigated and fertilized to minimize growth differences associated with competition from the bermudagrass. There were no differences in trunk diameter among treatments the first 2 years of the study. During the next 3 years, trunk diameter increased curvilinearly as the vegetation-free circle increased. A vegetation-free circle diameter of 1.83 m produced near maximum tree growth. Although trunk diameter improved slightly as the vegetation-free diameter was increased up to 7.32 m, it was not sufficient to justify the additional expense for herbicides nor exposure of unprotected soil to erosion.
M.S. Flanagan, R.E. Schmidt, and R.B. Reneau Jr.
The “heavy fraction” portion of a municipal solid waste separation process was evaluated in field experiments as a soil amendment for producing turfgrass sod. Soil organic matter and concentrations of extractable NO3-N, P, K, Ca, and Zn in the soil increased with addition of heavy fraction. Soil incorporation of heavy fraction resulted in greater air, water, and total porosity and lower bulk density of a loamy sandy soil. .Sod strength measurements taken 8.5 and 9.5 months after seeding were higher for Kentucky bluegrass (Poaprutensis L.) grown in heavy-fraction-amended topsoil than for turf grown in topsoil only. The use of this by-product may reduce the time required to produce a marketable sod. Soil incorporation of heavy fraction did not influence post-transplant rooting of Kentucky bluegrass sod but enhanced rooting of bermudagrass [Cynodon dactylon (L.) Pers.] sod at the highest rate evaluated. Results of these studies suggest that the use of heavy fraction for sod production may provide cultural benefits in addition to reducing the volume of solid waste deposited in landfills.
G.C. Munshaw, X. Zhang, and E.H. Ervin
Bermudagrass [Cynodon dactylon (L.) Pers.] is widely used along its northern limit of adaptation. However, cold hardiness and winter survival are common concerns facing turfgrass managers in these areas. The objective of this study was to determine the effects of moderate salinity applications on bermudagrass cold hardiness. Two trials were conducted in Summer 2002. The cultivar Princess was seeded into pots in a glasshouse at a rate of 24 kg·ha-1. Pots received a weekly solution of 20-20-20 at a rate of 4.9 kg·ha-1 N. Bi-weekly salinity treatments began ≈2 months after germination and consisted of 0, 5, 20, and 40 dS·m-1 in the form of NaCl. These treatments continued for ≈8 weeks. Weekly quality ratings and chlorophyll fluorescence measurements showed similar results, with the high salinity treatments having the poorest quality. Soil electrical conductivity measurements showed a significant increase for the high salinity rates over the lower rates at the end of the trials. Proline concentrations increased with increasing salinity treatments in Trial 1 and were highest with the 20 dS·m-1 rate in Trial 2. Plants were acclimated in a growth chamber, and artificial freezing tests revealed that the 5 and 20 dS·m-1 treatments had the highest percentage of regrowth after freezing. These results indicate that moderate applications of salt or the use of effluent water prior to hardening may be an important way to increase bermudagrass cold hardiness.