• Title/Summary/Keyword: Weed Science

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Weed Control Technology with Low Concentration Ethanol in Protected Cereal Crop Cultivation (비닐하우스 내 조 재배시 저농도 에탄올을 이용한 잡초억제 효과)

  • Hwang, Jae-Bok;Yun, Eul-Soo;Park, Chang-Young;Jung, Ki-Youl;Choi, Young-Dae;Jeon, Sung-Ho;Lee, Yong-Hwan
    • Korean Journal of Weed Science
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    • v.32 no.2
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    • pp.115-120
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    • 2012
  • Weed control is of fundamental importance when planting cereal crops, particularly during the establishment phase. Weeds compete for nutrients, water and light, and can severely threaten the survival and early growth of newly planted crops. Field experiment was conducted to evaluate the effect of ethanol treatment on the weed control efficacy in cereal crops in protected vinylhouse. Five treatments like water, 25 L, 50 L, 75 L, and 100 L per $m^{-2}$ at 2% ethanol were applied and covered with vinyl on 10 days before foxtail millet seeding. After that, foxtail millet seeds were sown on June 20 at $60{\times}10cm$ planting distance and weed control efficacy was recorded at 30, and 50 days after seeding based on the dry weight. Soil oxidation-reduction potential was recorded -200~-400 mV after treatment 2 days. Weed control efficacy of at 75 L, and 100 L per $m^{-2}$ was observed 92%, 84% in 2% ETOH, respectively. Yields of foxtail millet at 75 L, and 100 L per $m^{-2}$ were 1,570 kg $ha^{-1}$, 1,230 kg $ha^{-1}$, respectively.

The Weed Flora of Korean Mulberry Fields (뽕밭에서 발생하는 잡초 양상)

  • Lee, In-Yong;Kim, Chang-Seok;Lee, Jeongran;Song, Hee-Kun;Seo, Hyun-A;Choi, Kyung-Mi;Ji, Sang-Deok
    • Weed & Turfgrass Science
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    • v.4 no.2
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    • pp.85-94
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    • 2015
  • The weed flora in the mulberry fields were investigated in Suwon, Jeonju, and Buan in May, July, and September of 2014. The objectives of this study were to use the survey data for establishing weed control methods and to bring awareness of possible problematic weeds in the Korean mulberry fields. The survey was conducted in 53 regions, covering approximately $145,925m^2$. Altogether 153 weed species of 37 families were identified, of which 68 were annual, 39 species were biennial and 46 were perennial. The dominance was the highest with Digitaria ciliaris followed by Erigeron annuus, Chenopodium album, Echinochloa crus-galli var.crus-galli, Acalypha australis, Commelina communis etc. Exotic weeds presented 44 species with 28.8% of a total presence, of which Erigeron annuus was the highest, followed by Chenopodium album, Phytolacca americana, Conyza canadensis, Oxalis corymbosa etc. Especially, we should aware Senecio vulgaris, not controlled with glufosinate ammonium SL in the Korean mulberry fields because it was known as atrazine resistance in US, Canada, Germany etc. In the PCA plot, weeds presented in the mulberry fields were divided into two groups, Eclipta prostrata community and Stellaria aquatic community and weed flora of Suwon and Buan were different due to those only presented in Suwon.

Basic Features and Facts of Herbicide Evaluation for Efficacy and Phytotoxicity in Korea (제초제의 효능과 약해 평가상의 당면과제)

  • Yong-Woong Kwon
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.23 no.3
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    • pp.19-30
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    • 1978
  • Use of herbicides in Korean agriculture has increased rapidly in recent years accompanying with ever-increasing pressure of farm labor shortage. Herbicides occupied already the second place in the rank of pesticides consumption in 1977. The agricultural experiment stations have carried out over 50 trials of chemical weed control each year since 1968. These research works and registration trials contributed much to the present wide use of herbicides. The pesticide management act amended in 1977 requires reevaluation of pesticides for their efficacy every 5 year-term. However, the development of sound weed control program and recommendations has been hempered very much by the lack of qualified workers of weed control research in agricultural experiment stations and in the institute for pesticide registration trial. Critical review of the past research works on herbicide evaluation and the present status indicates strong need for 1) the characterization of the nature of local and national weed problem, 2) the improvement of ability of the staffs in charge of weed control research through appropriate training on the basics and experimental techniques, and 3) organization and activities of weed control research committee. Furthermore, the present article attempts to clarify commonly misled points in the establishment of herbicide evaluation plan, in the design and execution of field trials, and in the assessment of trial results of the past works from the viewpoint of the basic principles with some case studies for resolution of specific enigmas.

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Occurrence and Distribution of Weeds on Upland Crop Fields in Chungbuk Province of Korea (충북지역 주요 밭작물 재배지 발생 잡초 분포 현황)

  • Lee, Chae Young;Park, Jae Seong;Kim, Eun Jeong;Lee, Hee Du;Hong, Eui Yon;Woo, Sun Hee
    • Weed & Turfgrass Science
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    • v.4 no.3
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    • pp.209-218
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    • 2015
  • This study was conducted to investigate the weed occurrence and distribution on the upland crop fields (garlic, barley, potato, maize, red pepper, soybean and Chinese cabbage) at 795 sites in Chungbuk province of Korea from Apr. to Oct. in 2014. From the result of this survey, 188 weed species in 42 families were identified and classified to 96 annuals, 40 biennials and 52 perennials. Based on the occurrence ratio, the most dominant weed species in Chungbuk province upland crop fields were higher in the order of Portulaca oleracea (8.14%), Digitaria ciliaris (6.72%), Echinochloa crus-galli (6.55%), Rorippa palustris (6.00%) and Chenopodium album (5.89%). The composition of major occurred weed families, Compositae, Poaceae, Polygonaceae and Cruciferae were 19, 10, 7 and 6%, respectively. In the winter upland crop fields, the dominant weeds were in the order of Capsella bursa-pastoris (12.36%), Alopecurus aequalis (11.05%) and Stellaria alsine (8.42%). In the summer upland crop fields, the dominant weeds were in the order of Portulaca oleracea (8.58%), Digitaria ciliaris (7.18%) and Rorippa palustris (6.28%). Fiftythree exotic weed species were identified. The results of this study could be useful information for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods on the upland crop fields in Chungbuk province of Korea.

Weed Occurrence in Lowland Rice Field in Gyeongbuk Province (경북지역 벼재배답에서 발생하는 잡초 분포)

  • Kim, S.J.;Kim, Y.H.;Lee, W.H.;Choi, C.D.;Kim, C.Y.;Choi, B.S.
    • Korean Journal of Weed Science
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    • v.17 no.3
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    • pp.262-268
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    • 1997
  • The experiment was carried out to obtain the basic information of weed control in lowland rice field in Gyeongbug province. The results were as follows : In weed distribution on life cycle, annual weed was occupied by 56.5% and perennials were 43.5%, respectively. In morphological distribution of weeds, grass weed was 25.2%, sedges was 12.3% and broad leaf weeds was 62.5%. In particular, weed occurrence of grass weed was much more increased than that of 1971 and 1981 year. Dominant weed species was Echinochloa crusgralli, Sagittaria trifolia, Eleocharis kuroguwai and Monochoria vaginalis in plain land, mid alpine area, and cold salty wind area. Dominant weeds was approximately similar occurrence in normal soil and poorly drained soil Gelds, but sandy soil field was not. Echinochloa crusgalli was dominant in hand transplanting and direct seeding on dry paddy field. Meanwhile, in machine transplanting, Sagittaria trifolia and Ludwigia prostrate were dominant, and occurrence of Echinochloa crusgalli was increased to delaying transplanting. As a result, major dominant weed was Echinochloa crusgalli, Sagittaria trifolia, Ludwigia prostrate, Eleocharis kuroguwai, and Monochoria vaginalis in terms of predominance.

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Occurrence of Weed Species on Turf Sod Production Areas in Jangsung-gun, Jeonnam Province (전남 장성지역 한국잔디 재배지 잡초발생 현황)

  • Choi, Sung Hwan;Ahn, Soo Jeong;Lee, Dong Woon
    • Weed & Turfgrass Science
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    • v.5 no.4
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    • pp.247-255
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    • 2016
  • This study was conducted to provide basic information for weed control by surveying the occurrence of weed species in turf sod production areas. Surveys of weed species occurred in turf sod production areas were conducted in Jangsung-gun, Jeonnam province from September 2014 to May 2016. Total 50 sites of turf sod production areas in two soil conditions were investigated. On the upland soil condition in turf sod production areas, 66 weed species in 27 families were identified and classified to 49 annuals and 17 perennials and on the paddy soil condition, 69 weed species in 22 families were identified and classified to 53 annuals and 16 perennials. Based on the importance values, the most dominant weed species on the upland soil condition in the first survey (September 2014) was Digitaria ciliaris (8.49%), followed by Erigeron annuus (7.94%) and Rorippa indica (6.56%). In the second survey (May 2016) was Oxalis corniculata (7.26%), followed by Capsella bursa-pastoris (6.21%) and Conyza canadensis (6.21%). Whereas the most dominant weed species on the paddy soil condition in the first survey (September 2014) was Erigeron annuus (9.52%), followed by Mazus pumilus (7.41%) and Cyperus iria (6.82%). In the second survey (May 2016) was Commelina communis (5.08%), followed by Alopecurus aequalis (5.08%) and Erigeron annuus (4.79%). This information could be useful for estimation of future weed occurrence and effective weed control methods in turf sod production areas in Jangsung-gun, Jeonnam Province.

Distribution of Weeds with Different Surface Management Systems of Greenhouse Soil in Gyeongnam Province (경남지역 시설원예작물 재배지 및 표토관리별 잡초발생 양상)

  • Hwang, Jae-Bok;Yun, Eul-Soo;Park, Chang-Young;Park, Sung-Tae;Nam, Min-Hee
    • Korean Journal of Weed Science
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    • v.31 no.3
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    • pp.221-228
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    • 2011
  • Weed control is of fundamental importance when planting horticultural crops, particularly during the establishment phase. Weeds compete for nutrients, water and light, and can severely threaten the survival and early growth of newly planted crops. Failure to control weeds represents one of the single most important factors leading to crop loss. Knowledge on the existence of the diversity of weed species in greenhouses is of our main concern in this study in order to develop a most efficient and effective weed control strategies. Sixty-two greenhouses were surveyed in 3 cities and counties of Gyeongnam area in March to October 2009 to investigate the feature of weed occurrence in polyvinyl chloride (PVC) after harvesting of the main crops. Forty-one weed species were identified and classified to 18 families which were composed of 14 annual weeds, 18 summer annual weeds and 9 perennial weeds. On the other hand, broadleaf, grasses and sedges recorded with 30, 7 and 4 weed species, respectively. Asteraceae was the most dominant weed species (9 species) noted followed by Poaceae (7 species), Cyperaceae (4 species), Caryophyllaceae and Brassicaceae (3 species respectively) and other families have 1~2 species. The dominant weed species occurred in the greenhouse based on the summed dominance ratio. These weeds were Digitaria sanguinalis, Cyperus iria, Portulaca oleracea, Rorippa islandica, Mazus japonicas, Cardamine flexousa, and Eclipta prostrata and others. Weed occurrence in the greenhouse after horticultural crops consisted of summer annuals (4 species), winter annuals (3 species), and perennial annuals (1 specie). The dominant species occurred in tilled soil based on summed dominance ratio of weeds were Cardamine flexousa (88.1%), Eclipta prostrate (57.4%) and Portulaca oleracea (55.2%). Comparison of weed occurrence was thoroughly surveyed also in which field without PVC, weed species were Portulaca oleracea (55.2), Eclipta prostrata (57.9%) and Trigonotis peduncularis (25.1%) and field with PVC, the identified weeds were Portulaca oleracea (98.75), Trigonotis peduncularis (49.1%), and Eclipta prostrata (36.8%).

The Occurrence of Weed Species in Coix lacryma-jobi var. mayuen Fields (율무밭에 발생하는 잡초 양상)

  • Lee, In-Yong;Kim, Chang-Seok;Lee, Jeongran;Han, Jeong-A;Kim, Kyung-Hoon;Kim, Mi-Seon;Song, Hee-Kun;Kim, Duk-Hwan
    • Weed & Turfgrass Science
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    • v.3 no.2
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    • pp.102-109
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    • 2014
  • This study was conducted in order to utilize the basic data for weed control by surveying the occurrence of weed species and the degree of damages caused by those weeds occurred in cultivated Coix lacryma-jobi var. mayuen fields. Survey was carried out three times, from June to September in 2013. The weed flora was composed of a total of 98 weeds, 33 family, of which 58 species were annual, 21 species were biennial, and 19 were perennial plants. Thirty-one exotic species were included as well. Dominance was the highest with Digitaria ciliaris followed by Acalypha australis, Echinochloa crus-galli, Portulaca oleracea, Bidens frondosa etc. in order. In the PCA plot analysis, weeds occurred in C. lacryma-jobi var. mayuen fields were divided into three groups, Panicum dichotomitlorum community, Echinochloa crus-galli-Sigesbeckia pubescens community and Acalypha australis community. Yield of C. lacryma-jobi var. mayuen was reduced 60% in no weeding plots comparing to that in weed management plots.