• Title/Summary/Keyword: Ryegrass

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Occurrence Dollar Spot Caused by Sclerotinia homoeocarpa in Turfgrass of Golf Course in Korea (한국 골프장에서 Sclerotinia homoeocarpa에 의한 잔디동전마름병의 발생)

  • 심규열;민규영;신현동;이현주
    • Asian Journal of Turfgrass Science
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    • v.14 no.1
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    • pp.241-250
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    • 2000
  • In 1997, a new disease on creeping bentgrass and Kentucky bluegrass occurred in the green and fairway of a few golf courses in Korea. The disease spread gradually throughout the country and became a threat to turfgrass management. Symptoms of the disease consisted of small, circular, and sunken patches sized 3~5cm in diameter. The disease named as a dollar spot following its characteristic symptoms of circular blight and bleach on the green. The disease peaked two times in a year from April to June and from late August to October and white cottony mycelia of the causal fungus developed on diseased turfs in the early morning when the conditions were favored. A causal fungus was consistently isolated from the infected tufgrass and seven isolates originated from seven golf courses located in six provinces were selected for further study. The fungus produced abundant white aerial mycelia on PDA and turned to dark gray or light brown as it aged. Width of the mycelium was ca. $5~8\mu\textrm{m}$. While sclerotia were not readily formed on the medium, scattered small and dark colored stromata were developed on the surface. The fungus grew well on PDA between 5 to $30^{\circ}C$ and maximally around $25^{\circ}C$. Based on investigated mycological and cultural characteristics, the causal agent of dollar spot was identified as Sclerotinia homoeocarpa. The fungus showed strong pathogenicity to several turfs as creeping bentgrass, Kentucky bluegrass, perennial ryegrass, tall fescues, and zoysiagrass.

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The Efect of Phosphorus on Competition in Annual and Perennial Plants (일년생과 다년생 식물의 경합에 미치는 인산의 효과)

  • Chung, Chan;Jeon, Byong-Tae
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.12 no.1
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    • pp.1-5
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    • 1992
  • The purpose of this experiment was to determine the effect of soil phosphorus level on plant length, dry matter yield and competition in annual and perennial plants.The effect of phosphorus fertilizer on the plant length and dry matter yield was low in the perennial plant of Miscanthus sinensis, SaSa palmata and ilrtemlsia princeps, but was high in the annual plant of Polygonwn thunbergii and Echinochloa crus-galli.The plant length, density and dry matter yield of Italian ryegrass in individual natural community did not depend on relative photosynthetic photon flux density but on total and available phosphorus of soil.

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Comparative Studies of Optimum Utilization Methods by Pasture Types (초지형태에 따른 적합한 이용방법의 비교에 관한 연구)

  • Lee, J.K.;Jo, M.H.;Yoon, S.H.;Choi, S.S.;Ko, S.B.;Seo, S.
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.15 no.1
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    • pp.24-29
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    • 1995
  • This experiment was canied out to select the optimum utilization method by various pasture types at National Livestock Research Institute, Suwon in 1992 and 1993. Tne main plot was two pasture types. wfiich were mainly top-grass(orchardgrass dominated pasture) and mainly bottom-grass(perennial ryegrass dominated pasture), and the subplot was three pasture utilization methods (grazing, grazing after the 1st cutting, and alternate utilization of cutting and grazing). Average dry matter yields of pasture were not affected by pasture types, but there was significant difference(p <0.05) by pasture utilization methods. Daily DM production of pasture was increased with alternate utilization of cutting and grazing at two pasture types. Also, pasture availability is increased by mainly top grasses and alternate utilization of cutting and grazing. Soil phsical chracteristics are improved by alternate utilization of cutting and grazing. According to the results obtained from this experiment, it is suggested that alternate utilization of cutting and grazing is effective for dry matter yield, pasture availability and soil phsical characteristics regardless of pasture types in Korea.

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Effects of Grazing and Cutting System on the Dry Matter and Botanical Composition in the Different Seed Mixture Swards (목초 혼파조합별 방목 및 예취이용이 수량 및 색생구성에 미치는 영향)

  • 고서봉;송상택;백윤기;이종열
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.8 no.1
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    • pp.1-7
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    • 1988
  • This experiment was carried out to determine the effect of grazing and cutting system in the seven different seed mixture plots on the dry matter yield and botanical composition from October 1983 to November 1986 at 200m above the sea level in Cheju. The results obtained are summarized as follows: 1. Dry matter yield was increased more cutting system than that of grazing system during the first and second harvest year (P<0.01), but at the third harvest year grazed plot was increased (P<0.05). 2. Three-year average dry matter yield tended to be relatively higher with tall fescue mixture plots (T4 and T7) than without tall fescue mixture plots. 3. In botanical composition of the seed mixtures, orchardgrass was observed to be more dominate in cutting system, while perennial ryegrass was increased in grazed plots. 4. Tall fescue was dominated about 70-80% at the third harvest year, in the plot of both grazing and cutting system. 5. The percentage of ladino clover was slightly increased in grazed plot compared with cutting plots. However those of alfalfa and red clover were not influenced by grazing and cutting system.

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Test study on Flow Resistance for Some Selected Vegetations (식생 조도 계수 산정을 위한 선별된 식생에 관한 실험 연구)

  • Rhee, Dong-Sop;Woo, Hyo-Seop;Kwon, Bo-Ae;Ahn, Hong-Kyu
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.1291-1294
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    • 2006
  • 최근 자연형 하천에 대한 인식이 개선됨에 따라 식생은 하천 환경 개선과 하천 복원을 위해 가장 중요하게 여겨지는 요소이다. 제방 및 호안에 사용된 식생은 하천의 심미적 가치와 환경적인 가치를 증가시키며, 다른 재료와 복합적으로 사용되는 식생의 경우, 예를 들어 사석 갯버들 호안 등은 상당히 우수한 치수 안정성을 가지는 것으로 알려져 있다. 하지만 이러한 식생의 활용은 홍수 시 흐름 저항을 증가시켜 수위를 증가시키기 때문에 하천 설계 시 식생의 조도 계수를 정확히 평가하여 사용하는 것이 중요하다. 본 연구에서는 이러한 식생 조도 계수 산정에 관한 연구의 일환으로 일반 개수로에서 현재 제방에 널리 사용되고 있는 한국 잔디(금잔디) 및 양잔디(Perennial Ryegrass)를 선정하여 실험하였다. 두 식생 모두 완전 침수(fully submerged) 상태에서 실험을 수행하였으며, 유사한 유량 범위에 대하여 실험을 수행한 후 그 결과를 비교 분석하였다. 실험 결과 단위 폭 당 유량이 증가함에 따라 한국 잔디에 대해서는 매닝 조도 계수가 0.03 부근에 수렴하는 것으로 나타났으며, 양잔디에 대해서는 마찬가지로 단위 폭 당 유량이 증가함에 따라 0.06 부근으로 수렴하는 것으로 나타났다. 특히 한국 잔디에 대한 실험 결과는 기존 매닝 조도 계수 연구 결과 중 '홍수터-초지(작은 풀)' 조건에 대하여 설계 제안치로 제시되는 수치와 유사한 결과를 나타내는 것 을 확인할 수 있었다.

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Nitrogen Fixation of legumes and Cropping System for Organic Forage Production (두과 작물의 질소고정과 유기조사료생산을 위한 작부체계)

  • 이효원;박형수
    • Korean Journal of Organic Agriculture
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    • v.10 no.1
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    • pp.49-63
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    • 2002
  • In order to supply 85% of total organic feed in ruminants and 80% in non-ruminants for organic animal production, nitrogen fixation ability of legume should be used in domestic roughages production. 50% of Europe organic farmer use intercropping legume in as green manure. This article is dealing with amount of biologically fixed nitrogen used by legumes and methods for estimating the transfer of biologically fixed N in rotation and separating the N benefit into fixed N and non-fixed N components are reviewed. Available data indicate that transfer amount of N to non legumes was from 50∼9.6(kg/ha) in legume-cereal rotations and proportion of legume N varied with seasons, 90% in summer, 50% in autumn. The important point in cropping system for legumes have to be included for organic forage production 6 year rotation is based on pasture system of 3 year pasture + 2 year annual(com, sudangrass), again pasture. Rye, barly and Italian ryegrass+legumes(vetch, crimson and pea) can be one of option in spring, com, soybean, sudangrass and Japanese bamyard millet would be seeded after spring harvest in the field. Farmer can make good use of rice paddy field as forge production potential area after harvesting rice. Italian, burly and rye+vetch and crimsonclover may be grown in autumn or spring time at the rice field.

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Nitrate Metabolism Affected by Osmotic Stress and Nitrate Supply Level in Relation to Osmoregulation

  • Kim, Tae-Hwan
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.20 no.2
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    • pp.77-84
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    • 2000
  • Eight-week old perennial ryegrass (Lolium perenne L. cv. Reveille) plants were exposed to different NO3-concentrations or osmotic stress with NaCI. Previously labeled "N was chased during 14 days of non-labeled'NO3 feeding in order to investigate NO3 metabolism in relation to osmoregulation. The short termmeasurement of osmotic potential showed that the extemal concentration of Nos- had not great effect on theosmotic potential, but that osmotic adjustment was observed in NaCl-treated plants. Total uptake of NO 3 - waslargely increased by increasing supply level of NO3 while it was depressed by exposing to osmotic stress.Nitrate reduction increased to more than 29% by increasing extemal NO,- concentration from 1 mM to 10mM. When osmotically stressed with NaCI, nitrate reduction was depressed to about 37% as compared to thecontrol. The decrease in translocation of reduced N into leaves was also observed in NaCl exposed plants. Inthe medium exposed to 10 mM NO,., osmotic contribution of nitrate to cumulative osmotic potential wasdecreased, and it was osmotically compensated with soluble carbohydrate. When osmotically stressed withNaC1, the contribution of chloride was much higher than that of nitrate. The present data indicate that N03-in plant tissues, factually affected by the assimilation of this ion, plays an active role in osmotic regulation incorrelation with other osmotica such carbohydrate and chloride.(Key words : Nitrate metabolism, Osmotic stress, Nitrate supply level, Osmoregulation)ate supply level, Osmoregulation)

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Isolation and Structure Determination of Phytotoxins from a Phytopathogenic Fungus Bipolaris sorokiniana (식물병원균 Bipolaris sorokiniana로부터 제초활성 물질의 분리 및 구조결정)

  • Lim, Chi-Hwan
    • Korean Journal of Agricultural Science
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    • v.29 no.2
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    • pp.91-97
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    • 2002
  • Two phytotoxic compounds, 3-methoxybenzoic acid (MBA) and 3-hydroxy benzoic acid methyl ester (HBAME), were purified and structurally characterized by instrumental analyses from a culture of a phytopathogenic fungus, Bipolaris sorokiniana. During the isolation procedure, the toxic components were monitored by the assay using rice (Echinochloa crusgalli) and Italian ryegrass (Lolium multiflorum). These compounds had a molecular formula of $C_8H_8O_3$ and inhibited the root growth of the plant seedlings over 90% at a level of 1000 ppm. This is the first report of herbicidal activity of MBA and HBAME purified from B. sorokiniana.

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Analysis of Light Environment to Turfgrass Growth under the Roof Membrane on Stadium (경기장 지붕의 막구조가 잔디생육에 미치는 광환경에 대한 영향분석)

  • Joo Young Kyoo;Lee Dong Ik;Song Kyoo D.;Shim Gyu-Yul
    • Asian Journal of Turfgrass Science
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    • v.18 no.3
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    • pp.119-128
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    • 2004
  • This study was conducted to analyze the effect of roof membrane on light environment that influence on turfgrass growth under domed stadium. Roof structure on experimental plot was constructed with PTFE and PE same as Busan Asiad Main Stadium. Tested turfgrass species were combinations of cool-season grasses(Kentucky Bluegrass, perennial ryegrass, $KBG80+PR20\%,\;KBG33+PR33+Fine fescue33\%)$ and warm-season grasses(zoysiagrass, 'An-yang middle-leaf, 'Zenith', Bermudagrass) established with seeding or sodding. The experimental set-up and research work were initiated November 1999 and finished on August 2000 at near Busan Asiad Main Stadium. By the result of computer simulation of daylight radiant energies on the turf surface were lower than needs of normal sport turf growth. The shortage of radiant resulted pest infection on cool-season grass mixture compared with warm-season. But turf color and density showed the best results on Kentucky bluegrass or its mixture plot. Over all the results showed that the best quality of turfgrass growth was occurred on full sun area, and the next was under PTFE membrane. The application of artificial lighting system may increase the turfgrass growth under domed stadium(partially) covered with roof membrane.

EFFECT OF ADDITIONS OF POTASSIUM AND NITROGEN INTO PRESS CAKE ON MAGNESIUM UTILIZATION OF GOATS WITH RELATION TO WATER INTAKE

  • Kim, S.A.;Ohshima, M.;Kayama, R.
    • Asian-Australasian Journal of Animal Sciences
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    • v.1 no.1
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    • pp.33-41
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    • 1988
  • In a study about minerals cycling in grassland agro-ecosystem, investigation on relations among two minerals, potassium(K) and magnesium(Mg), and nitrogen(N) was performed. Four kinds of diets different in K and N levels were fed to four goats with a Latin-square method and $2{\times}2$ factorial design. As the basal diet, press cake silage prepared from Italian ryegrass was used because of its uniformity and comparatively low mineral concentrations. Supplementation of K and N were made using potassium bicarbonate and urea. In the experiment, it was clearly shown that high K concentration in the forage crops is the main reason of the low utilization of Mg in ruminant animals. However, high nitrogen intake resulted in the increase of magnesium retention, urinary potassium excretion, water intake and volume of urine and in the decreases of potassium intake minus urinary potassium excretion. The results of high nitrogen intake seemed to be produced in the following order;increase of urine, increase of water intake, increase of urinary potassium excretion, and decrease of intake minus urinary potassium excretion. The amount of potassium intake minus urinary potassium excretion had significantly close relationships with magnesium utilization and serum magnesium concentration. As a conclusion, higher nitrogen intake by ruminants seemed to be preferable for magnesium utilization through increased water intake and urinary potassium excretion, if the sufficient drinking water could be supplied to ruminants.