• Title/Summary/Keyword: creeping

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Growth Response of Bentgrass to Polymer Coated Urea (Bentgrass 생육에 미치는 Polymer Coated Urea의 효과)

  • ;;N.E.Cheistans
    • Asian Journal of Turfgrass Science
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    • v.11 no.2
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    • pp.97-104
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    • 1997
  • The objective of this study was to observe the differences in growth of creeping bentgrass turf to 'polymer coated urea fertilizer' and 'uncoated urea fertilizer', and to analyze durability of fertilizer effect with the 'polymer coated urea'. The experiment was initiated on June 3, 1996, at the Iowa State University Horticulture Research Station, north of Ames, Iowa. The experiment was conducted on an area of 'Penneagle' Creeping bentgrass(Agrostis palustris) maintained at fair-'way mowing height (1.3cm). The study was repeated at the same arrangement beginning on July 25, 1996. Visual quality data, clipping fresh and dry weight, and nitrogen(N) content in the clippings were taken weekly. Quality of the turf increased with increasing N rate. While quality ratings were higher for turf receiving polymer coated urea than for turf receiving uncoated urea at several times following treatment, but not significant. Fresh and dry clipping weights were quite variable during the trial. Visual quality rating and clipping yields improved with increasing rates of N but these differences were not statically significant between polymer coated and uncoated urea treatment. The durability of fertilizer efficiency in polymer coated urea was not last longer compare with uncoated urea from two weeks after treatment. Higher rates of N application increased the concentration of N in tissue but no significant differences between turf plots receiving polymer coated and uncoated urea. Key words: Polymer coated urea, Creeping bentgrass, Fertilizer, Turfgrass.

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Comparion of Vitality among Three Cool-Season Turfgrasses during Summer using Chlorophyll Fluorescence (엽록소형광을 이용한 하절기 동안 한지형 잔디 3종의 활력도 비교 분석)

  • Seok Chan Koh
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2021.04a
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    • pp.44-44
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    • 2021
  • 본 연구는 제주지역의 골프 코스에서 하절기 고온기간에 온도의 상승을 비롯한 다양한 환경변화로 인하여 생육 장애가 심한 한지형 잔디인 perennial ryegrass (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), creeping bentgrass (Agrostis palustris Huds.) 3종에 대하여 엽록소형광과 엽록소지수를 측정하여 골프 코스와 스포츠 필드에서 잔디 선정과 관리를 위한 기본적인 정보를 얻기 위하여 수행하였다. Fo 값은 3종 모두 하절기 초기에는 낮고 후기에 다소 증가하는 양상을 보였다. 그러나, perennial ryegrass의 경우는 하절기 초기와 후기 간의 Fo 값의 변화가 컸으며, 특히, 후기에 Fo 값은 다른 2종 월등하게 보다 높았다. Fm 값은 3종 모두 하절기 초기에는 낮고 하절기 후기에 증가하였으나 3종 간의 차이는 크지 않았다. 광계 II의 광화학적 효율의 척도인 Fv/Fm 값은 3종 모두에서 하절기 초기에 낮고, 후기에 다소 증가하는 양상을 보였으나, 하절기 후기에 Kentucky bluegrass와 creeping bentgrass는 perennial ryegrass에 비해 Fv/Fm 값이 다소 높아 하절기 고온에서도 보다 더 잘 적응하는 것으로 보인다. 엽록소지수는 perennial ryegrass와 Kentucky bluegrass에서는 뚜렷하게 하절기 초기에는 낮고 후기에 높은 양상을 보였으나, creeping bentgrass는 조사기간 내내 낮은 상태를 유지하였다. 이상의 결과로부터 Kentucky bluegrass가 하절기 후기의 고온이나 빈번한 강우에 의한 습한 조건에 가장 강하고, perennial ryegrass가 가장 취약한 것으로 사료된다.

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Identification and Pathogenicity of Rhizoctonia species Isolated from Turfgrasses (잔디에서 분리한 Rhizoctonia spp.의 동정과 병원성)

  • Lee, Du-Hyung;Choe, Yang-Yun;Lee, Jae-Hong;Kim, Jin-Won
    • The Korean Journal of Mycology
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    • v.23 no.3 s.74
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    • pp.257-265
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    • 1995
  • Morphological characteristics and pathogenicity of Rhizoctonia species causing blight diseases of turfgrasses were studied. The species were identified as Rhizoctonia cerealis Van der Hoeven, R. oryzae Ryker et Gooch, and R. solani $K{\ddot{u}hn}$ based on their morphological and cultural characteristics. Isolates of R. solani were assigned to anastomosis groups (AG) with cultural type 1 (1A), 2-2 (IIIB), and 2-2 (IV). R. cerealis, R. oryzae and R. solani induced sheath rot and foliar blight symptoms on creeping bentgrass (Agrostis palustris) and zoysiagrass (Zoysia japonica). Inoculation tests showed that disease severity with isolates of R. cerealis and R. oryzae were more serious to creeping bentgrass than zoysiagrass. AG 1(1A) isolates of R. solani were strongly pathogenic on creeping bentgrass, but moderate to zoysiagrass. AG 2-2 (III) isolates were moderately pathogenic to zoysiagrass, but weakly to creeping bentgrass. AG 2-2 (IV) isolates from zoysiagrass were moderately pathogenic to zoysiagrass, but weakly to creeping bentgrass.

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Comparison on the Changes in Non-structural Carbohydrate Concentration with Regard to Cold Tolerance of Zoysiagrass and Creeping Bentgrass (월동 기간 중 Zoysiagrass와 Creeping Bentgrass의 비구조 탄수화물 농도의 변화 비교)

  • Kim Dae Hyun;Jung Woo Jin;Lee Bok Rye;Kim Eun Ju;Kim Kil Yong;Kim Tae Hwan
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.25 no.1
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    • pp.57-64
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    • 2005
  • 월동기간 동안 zoysiagrass[Zoysia matrella(L.) Merr]와 creeping bentgrass(Agrostis palustris Hunds)의 저온 스트레스에 대한 탄수화물 대사 반응을 구명하기 위해 11월부터 이듬해 4월까지의 식물체내의 탄수화물 대사산물의 변화를 비교 분석하였다. Creeping bentgrass의 녹색도와 뿌리 성장은 온도변화와 거의 평행하게 변화하였으나 zoysiagrass는 뿌리 성장에 거의 변화가 없이 3월 말까지 담황색을 나타냈다. 11월부터 이듬해 1월까지 zoysiagrass에서 glucose와 sucrose 함량은 크게 높았고, 1월에서 4월까지 starch를 제외한 모든 탄수화물 화합물들의 감소의 정도가 현저하게 낮았다. Reeping bentgrass에서 fructan의 depolymerization이 2월 이후 단당류와 이당류의 감소와 일치했으나 zoysiagrass에서는 starch 가수분해가 11월부터 일찍이 시작되었다. 이상의 결과들은 creeping bentgrass와 비교 했을때 zoysisagrass 뿌리의 높은 비구조적 탄수화물의 농도가 저온 내성과 밀접한 관계가 있음을 잘 나타내어 주고 있다.

Investigation of Nutrient Contents at in Creeping Bentgrass, Kentucky Bluegrass, and Zoysiagrass in Early Winter (골프코스에서의 월동 전 크리핑 벤트그래스, 켄터키 블루그래스 및 한국잔디의 부위별 양분 함량)

  • Kim, Young-Sun;Kim, Tack-Soo;Ham, Suon-Kyu;Course Service Team of Bear Creel G.C, Course Service Team of Bear Creel G.C
    • Asian Journal of Turfgrass Science
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    • v.22 no.2
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    • pp.141-148
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    • 2008
  • This study was conducted to investigate nutrient content at shoot and root(contained runner in zoysiagrass) in creeping bentgrass, kentucky bluegrass and zoysiagrass before turfgrass dormancy. The shoot ratio of dry weight in creeping bentgrass, kentucky bluegrass and zoysiagrass was 12%, 27% and 25% and root ratio was 88%, 73% and 75%, respectively. The orders of nutrients contained in turf-grass were N>K>Ca>P>Mg>Na in plant tissues. The proportion of nutrients in tissue of creeping bentgrass, kentucky bluegrass and zoysiagrass was 17%, 28% and 34% in shoot and 83%, 72% and 66% in root, respectively. These results showed that nutrients in turf-grass tissue was contained more than 70% in root before grasses dormancy. In turf grass management, all grasses were required to fertilize sufficiently N, $K_2O$, CaO and $P_2O_5$ before winter.

Comparison of Vitality among Three Cool-Season Turfgrasses during Summer using Chlorophyll Fluorescence (엽록소형광을 이용한 한지형 잔디 3종의 하절기 활력도 비교 분석)

  • Koh, Seok Chan
    • Journal of Environmental Science International
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    • v.30 no.7
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    • pp.547-555
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    • 2021
  • To compare the vitality among cool-season turfgrasses under summer weather conditions and to obtain information to improve the management of turfgrasses in golf courses and sports fields., the chlorophyll fluorescence of three cool-season turfgrasses commonly planted on golf courses in the Jeju area was measured. The turfgrasses were perennial ryegrass (Lolium perenne L.), Kentucky bluegrass (Poa pratensis L.), and creeping bentgrass (Agrostis palustris Huds.). In perennial ryegrass and Kentucky bluegrass, the chlorophyll index was low in early summer and high in late summer. In creeping bentgrass, it remained low throughout the study. Fo tended to be low in the early summer and high in late summer in the three turfgrasses. However, the difference in Fo between late summer and early summer was markedly higher in perennial ryegrass than in Kentucky bluegrass or creeping bentgrass. Fm tended to be low in early summer and high in late summer, without obvious differences among the three turfgrasses. Fv/Fm, a measure of photochemical efficiency, was also low in early summer and high in late summer in the three turfgrasses. However, Fv/Fm in late summer was mostly higher in Kentucky bluegrass and creeping bentgrass than in perennial ryegrass, indicating that the former are more resistant to the high temperature and humidity of late summer. Furthermore, Kentucky bluegrass had a high chlorophyll index in late summer and would be most resistant to the harsh conditions of late summer.

Effect of IBDU Complex and Organic Fertilizers for Creeping Bentgrass in Golf Course (골프코스 Creeping Bentgrass에 대한 IBDU복합비료와 유기질비료류의 효과)

  • 함선규;김성태;김호준;이상기
    • Asian Journal of Turfgrass Science
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    • v.11 no.3
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    • pp.167-172
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    • 1997
  • This experiment was carried out to study an effect of organic fertilizer, IBDU complex and humate on the growth of creeping bentgrass(penncross) and the change of soil chemical characteristics. Results obtained are summarized as follows :1.Content of a total nitrogen in soil was increased in more IBDU complex and organic fertilizer than humate plot. 2.Content of a organic matter in soil was increased in organic fertiliter and humate plot. 3.CEC in soil was improved a little in humate-granular plot. 4.The yield of dry weight and leaf color 'was increased in more organic fertilizer than humate plot. 5.Root length was the most effective in humate plot.

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A Study on Clutch-disc Characteristics for the Torsional Vibration Reduction of the Drive-Line at Creeping (최저속주행시 동력전달계의 비틀림진동 저감을 위한 클러치특성 연구)

  • Chung, T.J.;Hong, D.P.;Kim, S.S.;Kim, S.S.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.3 no.2
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    • pp.102-111
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    • 1995
  • The non-periodic fluctuation of the engine torque appears to be the major source of the torsional vibration of the automotive driveline. The reduction of this torsional vibration has become a significant problem along with the requirements of higher performance. The torsional vibration of the automotive driveline can be reduced by smoothing the fluctuation by adjusting the torsional characteristics of the clutch-disc. Computer simulation of the driveline is a useful investigative tool on studying the torsional characteristics of the clutch-disc. In this paper, a dynamic model for the automotive driveline was developed, and the engine torque of the model were evaluated with experimental data. By executing a simulation using the model, it has become possible to obtain the clutch-disc torsional characteristics for reducting the torsional vibration at creeping.

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A study on the flash over characteristics in space and surface series air gaps (공간연면 직렬간극의 섬락방전특성에 관한 연구)

  • 김원섭
    • 전기의세계
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    • v.25 no.1
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    • pp.87-94
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    • 1976
  • The characteristic of flashover electric discharge has been brought to light in this paper for the situation in which the space and creeping gaps are laid out in series. The result of this study has disclosed the facts that the over all flashover characteristics have three kind of features such as unilateral increase after increase, and increase after decrease in compliance with varied layout method and relative magnitude of gap length, and accordingly there exist a ratio among the magnitudes of gap length and a proper layort method through which the over all flashover voltage reaches the highest. Also involved with this study is the theoretic analysis of flashover characteristics even in the case of creeping electric discharge from hand tip of the gauge, where the over all value of flashover voltage can be estimated from the peculiar value of flashover voltage and flicker voltage for the space and creeping gap within the extent of 5% error.

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High-Frequency Analysis of Electromagnetic Backscattering from an Ellipsoid (타원체의 역방향 산란 해석)

  • Shim, Jae-Ruen
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • v.9 no.1
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    • pp.685-688
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    • 2005
  • In this study, an efficient algorithm for the numerical search of the geodesic path of the creeping wave on a doubly curved surface is developed. The ellipsoid as a doubly curved surface is studied because of its three dimensional nature in that it can be used to simulate the body of an aircraft, or a missile body. Numerical result of the geodesic path on an ellipsoid is given.

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