Browsing by Author "Art Bruneau, Committee Member"

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    Establishment and Allelopathic Potential of Centipedegrass (Eremochloa ophiuroides (Munro) Hack.) in Utility Turf Areas.
    (2002-12-18) Gannon, Travis William; Joe Neal, Committee Member; Fred Yelverton, Committee Chair; Dan Bowman, Committee Member; Art Bruneau, Committee Member
    Field and greenhouse experiments were conducted to 1) evaluate the safety and effectiveness of weed control treatments while establishing seeded centipedegrass and 2) determine the allelopathic potential of centipedegrass. Centipedegrass tolerance to treatments applied at seeding and early postemergent was evaluated. Atrazine, simazine, or low rates of imazapic did not reduce centipedegrass ground cover compared to the control while select rates of sulfometuron and all rates of metsulfuron were injurious to centipedegrass when applied at seeding. All rates of imazapic, sulfometuron, atrazine, or simazine applied 6 weeks after seeding (WAS) (one-leaf to one-tiller growth stage) caused less than 15% phytotoxicity, while chlorsulfuron + mefluidide, or metsulfuron caused 16 to 83% phytotoxicity 56 DAT. When large crabgrass and centipedegrass were seeded together, large crabgrass emergence was reduced (48%) by atrazine applied at seeding compared to the control (89%). In atrazine treated flats, centipedegrass tiller production and cover were greater due to reduced interspecific competition from large crabgrass. These data indicate that where large crabgrass is present, centipedegrass can be established more quickly if appropriate herbicides are used at seeding or shortly thereafter. Germination and growth of indicator species were evaluated in response to treatment with soil leachates, leaf debris, and aqueous leaf extracts of centipedegrass. Incorporated centipedegrass leaf debris did not reduce lettuce germination, shoot weight, or root weight as compared to the control. However, shoot and root dry weight of radish were reduced with increasing rates of centipedegrass leaf debris. These data do not conclusively demonstrate centipedegrass has widespread allelopathic activity; however significant reductions in shoot and root dry weight of radish with increasing debris rate demonstrates a pattern of inhibition of one species against another fulfilling a requirement of allelopathic interactions.
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    Nitrogen Relations in Bermudagrass During Growth and Dormancy Cycles
    (2007-12-19) Wherley, Benjamin George; Thomas Rufty, Committee Chair; Daniel Bowman, Committee Co-Chair; Fred Yelverton, Committee Member; Wei Shi, Committee Member; Art Bruneau, Committee Member
    Use of recycled water for turfgrass irrigation is increasing in the southeastern U.S. because of population growth and interest in protecting water quality. Turfgrass systems are perceived to be well suited for effluent dispersal due to their proximity to waste treatment facilities, in-ground irrigation systems, and ability to efficiently absorb (i.e. filter) nutrient contaminants when actively growing. However, effluent generation is continuous and bermudagrass growth is seasonal in the southeastern U.S. Clearly, there is a need to more thoroughly understand the capacity of bermudagrass, the turfgrass most often involved with effluent dispersal, for receiving effluent irrigation. This series of experiments was designed with the overall intent of examining the capacity of a bermudagrass turf⁄soil system for handling effluent applications. Experiments involved 1) characterizing seasonal changes in nitrate assimilation efficiency of the system, 2) determining the effects of prolonged soil saturation on nitrate uptake efficiency, and 3) characterizing internal nitrogen relations during the spring emergence period. While it is difficult to extend the results of these experiments, quantitatively, to situations where effluent is being applied in the field, the evidence does support a few basic observations. Bermudagrass appears to be capable of assimilating large amounts of N when growing, an ability that may well extend into transition months when little vertical shoot growth is occurring. Furthermore, although reduction in quality occurred, shoot growth and nitrate uptake efficiency of bermudagrass and centipedgrass was relatively unaffected by prolonged saturated soil conditions, a condition that may be likely with effluent irrigated sites.