• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.1
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• pp.61-69
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• 1977

The affect of perennial weeds to rice yield and rice growing was evaluated. Rice heading date was shortened 1-4days and rice culm length was shortened 5-10cm in heavy weed growing condition. The ratio of yield reduction were about 50% in Cyperus serotinus, about 57 in Potamogeton distinctus in both rice varieties and about 60% of Eleocharis kuroguwal in heavy perennial growing condition.

• Korean Journal of Weed Science
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• v.12 no.2
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• pp.144-157
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• 1992

The study was conducted to compare the interprete methods and examine the feasibility of mixture use of oxyfluorfen and bensulfuron in controlling principal Paddy weeds, annuals and perennials. Application ratio of both chemicals were obtained from the combinations of 5 levels(0, 5, 10, 15, 20 g ai/ha) of each chemicals, respectively. All the treatments were applied at 5 days after transplanting and water was maintained at 3.0cm in depth. Shoot fresh-weight of weeds was assessed at 35 days after treatments. Data obtained was analysed by Colby, Isobole, Calculus, Regression and EQM method, respectively. The results from the analysis of variance on the principal weeds treated with oxyfluorfen and bensulfuron showed significant interactions at 1% level on both Echinochloa crus-galli and Eleocharis Kuroguwai, and total species at 0.5% level on both Potamogeton distinctus and Cyperus serotinus, but non significant on Scirpus juncoides and Sagittaria pygmaea. Thereafter, the results of the models applied to Echinochloa crus-galli, Eleocharis kuroguwai and total species were as follows ; 1. The Colby method gave values nearly identical to regression estimate method (both multiplicative models) as provided by Akobundu et al. The Colby method and Regression method indicated synergistic toward Echinochloa curs-galli, and total species, but antagonistic toward Eleocharis kuroguwai. 2. The Isobole method shows synergism on Echinochloa crus-galli at $ID_{50}$, and total species at $ID_{60}$ on Eleochari kuroguwai. 3. The Calculus method gave positive signs for the first differentiation and negative signs for the second differentiation except for some rates on Echinochloa crus-galli and total species, but reverse on Eleocharis kuroguwai. These result does not agree with the observed values. 4. ${\theta}$ value from the EQM method was greater than one at all combinations. This result was quite different from those of other methods. 5. The various models did not show the same results, but mixture of oxyfluorfen and bensulfuron tend to have synergistic effect. Weeding effect also was high. Treatment in terms of two chemical combination was expected to reduce rates, and to enhence weeding efficacy compared with single treatment.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.44-54
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• 1993

This experiment was conducted to understand the environmental factors affecting growth and tuber formation such as temperature, day length, tight intensity, water condition and cutting time of Eleocharis kuroguwai Ohwi. Plant height, shoot number and dry weight of E. kuroguwai were higher at high temperature, 25/$25^{\circ}C$ (day/night), while nitrogen content was higher at low temperature, 20/$15^{\circ}C$. Plant height was more affected by water temperature, while shoot number and dry weight were more affected by air temperature. Contents and absorption of nitrogen, phosphorus, and potassium in top parts of E. kuroguwai were higher under greater difference between air and water temperatures, i.e., 18/$28^{\circ}C$ and 28/$18^{\circ}C$. The number and weight of tubers were increased under greater difference between air and water temperatures, i.e, 18/$28^{\circ}C$ and 28/$18^{\circ}C$, while they were inhibited at low or high air/water temperatures (18/$18^{\circ}C$ or 28/$28^{\circ}C$). Tubers of E. kuroguwai were formed at 8-or 12-hour day length, however, no tuber was formed at l6-hour day length. Photoinductive period for tuber initiation of E. kuroguwai was between 30 and 45 days after emergence, and the induction period of short-day treatment was less than 10 days. Tuber number and weight were reduced by shading due to inhibition of the growth of top and underground parts. Number of days from planting to tuber initiation was shortned as planting time was delayed and plant height, dry weight, and tuber number were also reduced by delayed planting. Tuber number at l0 to 15cm water depth was decreased 63 to 75% as compared with 1 to 5cm water depth. Tuber number and dry weight were not affected by the size of tubers at planting. Due to the reduced growth of top and underground parts, tuber number and dry weight of E. kuroguwai were decreased by delayed shoot cutting. The critical cutting time to inhibit the growth of E. kuroguwai was about 70 days after emergence.

• The Korean Journal of Ecology
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• v.12 no.4
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• pp.237-244
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• 1989

The moor vegetation of Daeryong-po on Mt. Daeam, east-central Korea was investigated in July 26th-29th, 1989, It was classified into I community group, 4 communities and 5 subcommunities; Sanguisorba tenuifolia var. alba community group, Sphagnum palustre community. Typical subcommunity, Eleocharis mamillata var. cyclocarpa subcommunity, Carex canescense subcommunity, Carex dispalata community, Spiraea salicifolia community, Geranium eriiostemon var. megalanthum community, Arundinella hirta-Phragmites communis subcommunity, Angelica purpuraefolia subcommunity. According to this classification, the actual vegetation map was made. The distribution of vegetation in this moor was divided characteristically into two areas. One was a typical oligotrophic area characterized by S. palustre community. The other was an area having mesotrophic or eutrophic conditions where its original state was disturbed by inflow of soil particles and removal of peat. It this disturbed area, C. dispalata, S. sibiricus, G. eriostemon var. megalanthum, were invaded.

• Korean Journal of Weed Science
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• v.2 no.1
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• pp.41-46
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• 1982

Herbicidal effectivity on perennial paddy weeds such as Sagittaria pygmaea Miq. and Eleocharis kuroguwai Ohwi was evaluated. Herbicides used were butachlor [2-chloro-2, 6-dietyl-N(butoxymethyl)-acetanilide], benthiocarb [S-(4-chlorobenzy)-N, N-diethyl-thiocarbamate], molinate (S-ethyhexahyaro-l-Hazpine-carbothiate], SW-751, Chlormethoxynil (2.4-dichlorophenyl-3-methoxy-4-nitrophenyl-ether), CNP (2.4.6-trichlorophenyl-4-nitrophenylether),oxadiazon [2-tertbutyl-4-(2.4-dichloro-S-isopropoxyphenyl)-5-OXO-1.3.4-Oxadiazoline], dinuron [1-dimethyl-benthyl)-3-pheratrylurea], bentazon [3-isopropyl-IH-2.1.3-benzothiadiazine-(4)3H-one-2.2-dioxide], ACN (3-chloro-2-amino-l.4-naphthoquinone), MCPB [4-(2-methyl-4chlorophenoxy), butyric acid], 2.4-D (sodium 2.4-dichlorophenoxy acetic acid), MCP) sodium 2-methyl-4-chlorophenoxy acetic acid), SST-5, TH 63. Graszin D (Bentazon/2.4-D) and Graszin M (Bentazon/MCP) Herbicidal effectivity was divided into three types. Type I was the complete control both leaf and tuber, and SW-751 was belonged to this type. Type II was the partial control that exhibit complete control within certain period after herbicide application. After a certain period, however, the lateral bud have the germinability and grow normally, there after. Chloromethoxynil, CNP, ACN, and Oxadiazon were belonged to this group. Type III was no control at all. For E. kuroguwai, application of CNP, Chloromethoxnil, Oxadiazon and SW-751 gave good control in the early stage shile 2.4-D, MCP, bentazon and glaszin-D controlled well the intermediate stage application. Based on this results, E. kuroguwai can be controlled by herbicide application either in the early stage or in the intermediate stage.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.25-32
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• 1986

This experiment was conducted to evaluate effect of various hormones on callus induction, and on plantlet formation on various media, and to detect of Londax [Methyl 2-[[[[[(4,6-dimethoxy pyrimidin-2-yl) amino] carbonyl] amono] sulfonyl) methyl] benzoate] and Basta[Ammonium-(3-amino-3-carboxy-propyl)-methyl phosphinate] on callus growth and reaction of succinate dehydrogenase in callus against TTC, using various species such as Eleocharis kuroguwai, Cyperus serotinus, Oryza sativa (samgangbyeo) and Echinochloa crusgalli P. Beauv. var. caudata Kitagawa. The optimal levels of 2,4-D in MS medium seems to be different among species tested, 2.0 ppm for rice and E. crusgalli, 1.0 ppm for Eleocharis kuroguwai, and 4.0 ppm for C. serotinus derived callus from shoot-tip. In case of combination of 2,4-D with BA, 1.0 plus 0.3 ppm appeared the most appropriate level to induce callus from rice and E. kuroguwai, and I.0 plus 0.1 ppm for C. serotinus and E. crusgalli. When 2,4-D treated with TIBA, 1.0 plus 0.5 ppm appeared the most appropriate rates to induce callus derived from seeds of rice, E. crusgalli, seeds of C. serotinus and E. kuroguwai, 1.0 plus 0.3 ppm for shoot-tip of C. serotinus. Positive reaction of succinate dehydrogenase against TTC was observed regardless of calli and herbicides tested, indicating that they all are alive, and these herbicides were not able to kill the calli tested within the short period of time 20 hrs treatment. Regardless of plant species used, the rate of plantlet formation from callus was very low. However, some plantlet formed from E. crusgalli at 0.8 ppm of 2,4-D plus 8.0 ppm of kinetin, and from E. kuroguwai at 1.6 ppm of 2,4-D plus 16.0 ppm of kinetin, showing effectiveness of 2,4-D with kinetin mixture treatment. No callus was induced from C. serotinus treated with Basta from $10^{-6}M$ to $10^{-3}M$. In general, rice was the least susceptible to Basta among plant species tested, followed by E. crusgalli, and E. kuroguwai. In Londax treatment, rice showed the least inhibition rate in callus growth. Callus was induced from rice even at $10^{-3}M$ of Londax. However, $10^{-3}M$ of Londax completely inhibited callus induction from the test species. Rice showed most tolerant to both herbicides, indicating the existence of different responses among plant species.

• The Korean Journal of Ecology
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• v.26 no.5
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• pp.281-287
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• 2003

We present the first analysis of moor vegetation on the Moojechi of Ulsan including syntaxonomy and syndynamics. We classified plant communities according to the Braun-Blanquet approach. In order to better understand ecological alteration processes and changing species compositions along successional gradients we also examined synecological differences using Principal Coordinate Analysis(PCoA) in terms of moisture gradient, species richness, and community structure. Classification resulted in one association and five plant communities occupying distinct moor habitats: Hypericum laxum-Eleocharis acicularis for. longiseta community, Drosera rotundifolia-Eleocharis congesta community, Platanthero-Molinietum japonicae ass. nova hoc loco, Molinia japonica-Alnus japonica community, Miscanthus sinensis-Pinus densiflora community, and Convallaria keiskei-Quercus serrata community. Due to synecological correspondences and floristic similarities in supraregional perspective, Platanthero-Molinietum can be assigned to existing higher syntaxonomic units of Molinion and Molinietalia in Braun-Blanquet system, established in Japan. We propose to extend their range and designate the new class Molinietea japonicae representative to the intermediate moor (Zwischenmoor) vegetation in Northeast Asia. PCoA resulted in four types showing a sequencess of succession: Needle spike-rush type, moor-grass type (incl. alder forest type), eulalia type, and oak forest type. A combination of edaphic conditions (soil eutrphication and soil moisture) and hydrologic patterns of moor ecosystem related to topography, occurring as result of external geophysical forces, controls inter alia spatial patterns and floristic compositions of moor plant communities.

• 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.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.205-210
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• 1991

The freezing resistance of Eleocharis kuroguqai was evaluated in artifical and natural freezing conditions in relation to tuber size, depth of tuber burial and soil moisture conditions. Osmotic potential of immature and mature tuber of E. kuroguqai before hardening was -12.1 and -23.5 bar, respectively, but decreased to -61. 0 and -67.1 bar after 120-day hardening period. Percent survival of E. kuroguqai tubers during the winter period was 13% and 67% in dry and moist moisture conditions at burial of 5cm depth, but all tubers were survived in the three moisture conditions employed when buried at 25cm depth. Greater decrease of osmotic potential was observed in tubers buried at 5cm depth than tubers buried at 25cm depth, resulting in greater freezing resistance in the former. Large tuber was more susceptable to freezing temperatures than small tuber.

• Weed & Turfgrass Science
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• v.5 no.1
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• pp.1-4
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• 2016

The Rural Development Administration of Korea conducted a series of surveys of paddy weeds from 1971 to 2013 in approximately 10-year cycles and the results have been used for the efficient weed management of paddy fields. In 1971, annual weeds such as Rotala indica, Eleocharis acicularis f. longiseta, and Monochoria vaginalis were dominant. In 1981, the population of Echinochloa species decreased whereas broadleaf weeds such as M. vaginalis, Sagittaria pygmaea, and S. trifolia were dominant. In 1991, perennial weeds such as Eleocharis kuroguwai, S. pygmaea, and S. trifolia were dominant over annual weeds. In 2000, M. vaginalis was the most abundant species, followed by E. kuroguwai, Echinochloa species, and S. trifolia. In 2013, herbicide-resistant Echinochloa species and M. vaginalis were most dominant, followed by E. kuroguwai, Scirpus juncoides, and S. trifolia. It has been predicted that the prevalence of Echinochloa species will continue to increase and that perennial weeds will be more abundant than annual ones in the near future. The occurrence of herbicide-resistant weeds and exotic weeds will also increase due to global warming and changes in agricultural patterns.