• 제목/요약/키워드: Turf

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SPH Modeling of Hydraulics and Erosion of HPTRM Levee

  • Li, Lin;Rao, Xin;Amini, Farshad;Tang, Hongwu
    • Journal of Advanced Research in Ocean Engineering
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    • 제1권1호
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    • pp.1-13
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    • 2015
  • Post-Katrina investigations revealed that most earthen levee damage occurred on the levee crest and landward-side slope as a result of either wave overtopping, storm surge overflow, or a combination of both. In this paper, combined wave overtopping and storm surge overflow of a levee embankment strengthened with high performance turf reinforcement mat (HPTRM) system was studied in a purely Lagrangian and meshless approach, two-dimensional smoothed particle hydrodynamics (SPH) model. After the SPH model is calibrated with full-scale overtopping test results, the overtopping discharge, flow thickness, flow velocity, average overtopping velocity, shear stress, and soil erosion rate are calculated. New equations are developed for average overtopping discharge. The shear stresses on landward-side slope are calculated and the characteristics of soil loss are given. Equations are also provided to estimate soil loss rate. The range of the application of these equations is discussed.

깎기주기, 통기작업, 시비수준 및 비료종류가 한국 잔디의 품질 및 생육에 미치는 영향 (Effect of mowing interval, aeration, and fertility level on the turf quality and growth of zoysiagrass( Zoysia japonica Steud.))

  • 황연성;최준수
    • 아시안잔디학회지
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    • 제13권2호
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    • pp.79-90
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    • 1999
  • This study was conducted to provide basic understandings for proper management of zoysiagrass fairways. Mowing intervals of 2, 4 and 6-days, with and without aeration were compared at two fertility levels. Turfgrass quality, growth and pest infestation were evaluated. Turf density, number of tillers, leaf width and resiliency were significantly affected by mowing frequency. Turfgrass plots mowed every 2-day had greater density, tillering, and resiliency but had narrower leaf width compared to other mowing treatments. Clipping dry weight with every 2-day mowing increased in the early stage of mowing treatment regardless of fertilizer application rates but gradually decreased in the later stage of mowing treatment compared to every 4 or 6-day mowings. The dry weight of above-ground part was not affected by mowing frequency, but that of underground part was significantly higher for every 6-day mowing frequency(3.3kg/day/m2) compared to every 2 or 4-day mowings. The organic mater content in soil was not different among mowing treatments but it was significantly reduced by the core aerification treatment, indicating significant effect of core aerification on thatch decomposition. Occurrences of weeds such as annual bluegrass and crabgrass according to mowing frequency were greater in every 2-day mowing treatment, while plots mowed every 6 days had less weed occurrence. Occurrence of rusts significantly increased in high fertility plots and frequently mowed turfgrasses.

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질소 및 가리 급원이 들잔디(Zoysia japonica Steud.)의 생육 및 품질에 미치는 영향 (Effects of Nitrogen and Potassium Sources on the Growth and Quality of Zoysia japonica Steud.)

  • 황규성;이용범;한동욱
    • 아시안잔디학회지
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    • 제5권1호
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    • pp.1-10
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    • 1991
  • The purpose of the experiment was to determine the effect of nitrogen sources (urea, ammonium sulphate, ammonium nitrate) and potassium sources (potassium chloride, potassium sulphate) on the growth and quality of Zoysia japonica Steud. This experiment was conducted at Seoul City University turf field from 1988 to 1989. The results of this experiment were summarized as follows; 1. Urea and Ammonium sulphate resulted in superior clipping yield compared to ammonium nitrate. The growth of rhizome and stolon increased significantly with urea forms, but ammonium sulphate treated plots exhibited the highest the growth rate of root. 2. Ammonium sulphate showed best turf color rating while ammonium nitrate resulted in the poorest. Prolongation of the green period showed longer in ammonium sulphate and urea treated plots than ammoium nitrate. 3. Urea and ammonium sulphate exhibited superior visible quality and shoot density compared to ammonium nitrate. 4. The uptake of mineral nutrient showed the highest concentration with urea plots. Surface soil pH was allowed to become slightly acid with the ammonium sulphate and potassium sulphate treatments, while the application of N and K sources did not cause significant differences in mineral element content in soil.

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현무암쇄석을 충진한 토양피복형 접촉산화공정의 오염물질제거효율에 관한 연구 (Efficiency of Nutrients Removal in a Microbial Contact Oxidation System Covered with Soil)

  • 최철호;이승목;윤종화;황필기;김정용
    • 한국물환경학회지
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    • 제21권1호
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    • pp.92-98
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    • 2005
  • Nutrients removal performance of a contact oxidation reactor covered with soil was investigated when basalt rubble was used as a contact medium under various operating conditions. The objective of the experiment was to determine the effectiveness of the system by measuring the removal efficiencies of nutrients from a technical and economical viewpoint. Under the ranges of HRT(20 and 40 hrs) in the experiment, the removal rates of organic matter were as high as 97.5% by showing an effluent $BOD_5$ of less than 10 mg/L. The test of nitrogen removal when the turf was planted on the top soil showed that the average removal rate increased as much as 25% as compared to that without planting. It was suggested that the construction and maintenance cost could be reduced over 20% when the HRT of the system was decreased from 72 to 40 hrs.

신규 잔디 제초제 메티오졸린(methiozolin) 개발 (Development of The New Turf Herbicide Methiozolin)

  • 구석진;황기환;전만석;김성헌;임종수;이동국;정근회;고영관;류재욱;구동완;우재춘
    • 한국잡초학회지
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    • 제30권4호
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    • pp.323-329
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    • 2010
  • Methiozolin (5-(2,6-difluoro-benzyloxymethyl)-5-methyl-3-(3-methyl- thiophen-2-yl)- 4,5-dihydro-isoxazole) is a new turf herbicide in isoxazoline chemistry. The herbicide controls grass weeds and has a high safety to various cool and warm season turfgrasses. This paper describes basic chemical, biological, and regulatory information of methiozolin.

유용미생물의 시용이 잔디의 질과 이용성에 미치는 영향 (The use of beneficial microorganisms to improve turfgrass quality and usability)

  • 황연성;최준수
    • 아시안잔디학회지
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    • 제13권4호
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    • pp.201-212
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    • 1999
  • In use of pesticides in golf courses has been increased steadily. Environmental concern as well as decrease in efficiency led the turfgrass management into an alternate approach of using beneficial microorganism to deal with turfgrass pests. This study was focused on the use of such microorganisms for improving cultural environment and minimizing the use of pesticides. Microorganisms antagonistic to turfgrass diseases were applied to zoysiagrass fairways and creeping bentgrass greens in Yusung country club. Tharch accumulation, disease occurrence, and other cultural environments were compared among the combinations of microorganisms and suppliemental N applications. The application of microorganisms antagonistic to turfgrass diseases improved turf resiliency. Thatch thickness was 3.03cm in the control plot but it was 2.11cm in plots treated by microorganisms, indicating significant effects of microorganism application on reduction of thatch accumulation. Number of microorganism that can decompose of cellulose was higher at the plots treated with useful microbial products and it was considered that existence of higher population of microorganisms resulted in reduction of thatch accumulation. In the evaluation of relationship between thatch accumulation and disease occurrence, greater thatch accumulation was observed at the golf courses which have been frequently infested by large patch. However, the rate of thatch accumulation varied among surveyed golf courses regardless of the year of turf establishment. Therefore, management practice which can be effective for reduction of thatch could result in large patch suppression. The application of microorganisms on the established turfgrasses reduced the occurrence rate of pythium blight and yellow path diseases, whereas occurrence of brown patch and dollar spot increased.

한국(韓國)에서의 Curvularia에 의한 잔디의 입고병(立枯病)에 관(關)한 분류학적(分類學的) 연구(硏究) (The Taxonomical Studies of Curvularia Blight of Turf (Arostis canina L.) in Korea)

  • 김종희;이민웅
    • 한국균학회지
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    • 제1권2호
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    • pp.31-33
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    • 1973
  • On September 1972, a blight disease of turf (Arostis canina L.)was found in a golf link in Seoul Country Club at Seoul, Korea. Yellow circular patches of 15-20cm in diameter were observed and spreaded irregulary to collapse of themselves. The roots of the diseased plants were dark in color and were in a final state of decay. We isolated Curvularia sp. from the diseased plants and investigated the morphological and cultural characters. Its characters as follows: Mycelia septate, branched, hyaline or yellowish brown colored. Conidiophores septate, thin brown, unbranched. $65-270{\times}3.5-5{\mu}$. Conidia clustered at the tips of conidiophores, boat form or slightly curved with 1-5 septa, brown; both end cells hyaline; the third cell much larger than the others. $26.1-33.3{\times}9.5-10.1{\mu}$ (4 cell's conidium). The pathogenicity of the fungus to host plant was confirmed by soil inoculation method. We classified the fungus according to Gilman's method as a species Curvularia geniculata (Tracy and Earle) Boedjin.

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Mitigating the Urban Heat Island Phenomenon Using a Water-Retentive Artificial Turf System

  • Tebakari, Taichi;Maruyama, Tatsuya;Inui, Masahiro
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2010년도 학술발표회
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    • pp.91-100
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    • 2010
  • To investigate the thermal properties of a water-retentive artificial turf system (W-ATS), we estimated hydrologic parameters including thermal conductivity, heat capacity, and surface albedo for both the W-ATS and natural grass. We used a model experiment to measure surface temperature and evaporation for both the W-ATS and natural grass. We found that the W-ATS had lower thermal conductivity than natural grass did, and it was difficult for the W-ATS to convey radiant heat to the ground. Compared to natural grass, the W-ATS also had lower heat capacity, which contributed to its larger variation in surface temperature: the W-ATS had higher surface temperatures during daytime and lower surface temperatures during nighttime. The albedo of the W-ATS was one-quarter that of natural grass, and reflected shortwave radiation from the W-ATS surface was lower than that from the surface of natural grass. These results indicate that the W-ATS caused the soil temperature to increase. Furthermore, evaporation from the W-ATS was one-quarter the value of evapotranspiration from natural grass.

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