• Weed & Turfgrass Science
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• v.3 no.2
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• pp.86-94
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• 2014

Survey was carried out in paddy fields to investigate the dominance of weed species and weed occurrence on 200 fields of southern Gyeonggi region in Korea during the year 2013. We observed 3 species of grass, 5 species of sedge, and 11 species of broadleaf and other weeds. The most dominant weed species was Eleocharis kuroguwai, followed by Echinochloa crus-galli, Sagittaria trifolia, Monochoria vaginalis, Scirpus juncoides and Bidens tripartita. The dominance value of E. kuroguwai and B. tripartita decreased compared to the survey results performed in 2005 but that of M. vaginalis, S. juncoides, S. trifolia and E. crus-galli increased. Weed occurrence increased from 2.83 g in 2005 to 3.51 g in 2013 based on weed dry weight per $m^2$. Occurrence ratio of annual weeds to perennial weeds changed from 45.2% : 54.8% in 2005 to 45.8% : 54.2% in 2013. If we analyze dominance of weed species based on the rice transplanting timing, E. kuroguwai and E. crus-galli were the most dominant weed species at mid-May transplanting, and M. vaginalis and S. juncoides were the most dominant weed species at late- May transplanting, and M. vaginalis and E. kuroguwai were the most dominant weed species at early-June transplanting. Since paddy weeds resistant to sulfonylurea herbicides are expected to be continuously increased, the regular monitoring of their occurrence and efficient control methods should be considered in future.

• Korean Journal of Weed Science
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• v.12 no.1
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• pp.46-51
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• 1992

The survey of weed population in paddy field was carried out to invegstigate the weed group on 340 fields in Kyonggi Area in 1991. The weed species observed include 4 species of grasses, 7 species of sedges, and 14 species of broadleaf weeds, and the ratio of annual weed vs perennial weed was 25 : 75. Major dominant weed species were Eleocharis kuroguwai, Sagitaria trifolia, Echinochloa crusgalli and Cyperus serotinus. The dominant weed species in South Plain Region were Echinochloa crusgalli, Eleocharis kuroguwai, Sagitariu trifolia, Cyperus strotinus, in West Coast Region were Eleocharis kuroguwai, Sagitaria trifolia, Echinochloa crusgalli, Cyperus serotinus, in East Interior Region were Eleocharis kuroguwai, Sagitaria trifolia, Echinochloa crusgalli, Cyperus difformis and were Sagitaria trifolia, Eleocharis kuroguwai, Echinochloa crusgalli and Monochoria vaginalis in North Region. The dominant weed species in Normal and Poorly drained soil were Eleocharis kuroguwdi, Sagitaria trifolia, Echinochloa crusgalli and Cyperus serotinus and were Scirpus maritinus, Cyperus serotinus, Echinochlod crusgalli and Myriophyllum verticillatum in Saline Soil. More and many weeds were growing in single cropped field than double cropped field.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.282-291
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• 1996

This experiment was conducted to investigate the phytotoxicity of several herbicides for rice and weed control with herbicides application times and seeding times in flooded direct-seeded rice field. The phytotoxicity of herbieides(bensulfuron methyl+dimepiperate, bensulfuron methyl+mefenacet+dymron, bensulfuron methyl+quinclorac, pyrazosulfuron-ethyl+molinate, pyrazosulfuron-ethyl+thiobencarb, pyrazosulfuron-ethyl+cyhalofop, imazosulfuron+molinate, imazosul-furon+cyhalofop) for rice in different seeding dates was the most high at 7 days after seeding(DAS) Followed by 12 and 17 DAS. In particular, the bensulfuron methyl+mefenacet+dymron showed very high phytotoxicity to rice plants. Weed species occurred in direct-seeding field seeded on May 1 were 10 species (grasses ; 1, broad-leaves ; 6, sedges ; 3) and Echinochloa crus-galli was the most dominant weed among them. Whereas weed species occurred rice field seeded on May 22 were 7 species(grasses ; 1, broad-leaves : 3, ridges ; 3) and Echirochloa crus-galli was the most dominant weed among them. The weed control for annual weeds(Echinochloa crus-galli, Aneilema keisak, and so on) and perennial weeds(Cyperus serotinus, Scipurus juncoides) was remarkably effective at the application of 7 and 12 DAS, but it of Eleocharis kuroguwai was effective at the application of 17 DAS on two seeding times. The yields were decreased significantly at the plot affected severely by herbicides applied at 7 DAS and the plots showed low efficacy at herbicides application of 17 DAS.

• Weed & Turfgrass Science
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• v.4 no.1
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• pp.44-48
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• 2015

This study was conducted to evaluate the efficacy of weed control and phytotoxicity of oxyfluorfen using a transgenic rice line (CPPO06 event) resistant to protoporphyrinogen oxidase (Protox) inhibiting herbicides in the direct-seeding flooded rice. Five annual weeds including Echinochloa oryzoides and two perennial weeds were occurred in the test field. Oxyfluorfen at 120 g a.i. $ha^{-1}$ in the application timing of two days before sowing and 0 and five days after sowing showed more than 90% weed control value except for Juglans mandshurica. Total weed control value was more than 95% in any application timing indicating a highly effective herbicide in the direct-seeding flooded rice. When compared with untreated control, no visual injuries were detected at single and double dosage of oxyfluorfen. The agronomic characteristics and yield components of CPPO06 event was reasonable in any time of application in this study. Based on these data, oxyfluorfen application before and after sowing can be applied to provide effective weed management in the direct-seeding flooded field.

• Weed & Turfgrass Science
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• v.4 no.1
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• pp.10-17
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• 2015

This study was conducted to investigate the occurrence of weed flora in pastures in Jeju island of Korea and to establish the basic data for controlling them occurred in the pastures. Weed flora was investigated twice, May and July on 2003. There were a total of 207 weed species including 49 families. Among them 67 species were annual, 39 species were biennial and 101 species were perennial. The compositions of major plant families, Asteraceae, Poaceae, Polygonaceae, Rosaceae, Fabaceae were 17, 15, 8, 7, 6%, respectively. Sixty-eight species of exotics were occurred, as well. Rumex obtusifolius was the highest in importance analysis and the followings were in order of Trifolium repens, Artemisia princeps, Plantago asiatica, Potentilla anemonefolia and Rumex acetosella etc. Among the exotic weeds, R. obtusifolius, T. repens, R. acetosella and C. holosteoides var. hallaisanense might be most problematic weeds species in pastures in Jeju island in the future. And at the boundary of some pastures and mountains Smilax china, Duchesnea indica, Rosa maximowicziana, etc. 17 shrub species were also occurred.

• The Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.1-12
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• 1999

Herbicidal activities of newly synthesized experimental compound, KSC-13906 [Erythro N-{(4,6-dimethoxy pyrimidin-2-yl)aminocarbgnyl}-2-(2-fluoro-1- hydroxy-n-propyl)benzenesulfonamide, US Patent 5,461,025], were investigated in greenhouse and field for development as a paddy herbicide. KSC-13906 exihibited excellent weeding effects and selectivity to rice under submerged paddy condition in geenhouse. At the application rate of $2.5{\sim}5$ g ai/ha treated on surface of water, KSC-13906 effectively controlled three annual weeds such as Echinochloa crus-galli var. oryzicola. Scirpus juncoides, and Monochoria vaginalis as well as five perennial weeds such as Cyperus serotinus, Sagittaria pygmaea, Eleocharis kuroguwai, Potamogeton distinctus, and S. trifolia. However, there was no effect on Aneilema keisak and Lindernia procumbens. Especially, KSC-13906 effectively controlled Echinochloa crus-galli var. oryzicola at growth stages ranging from pre-emergence to 3-leaf stage. Antagonistic interaction was found between pyrazosulfuron-ethyl and mefenacet, but not between KSC-13906 ana mefenacet. KSC-13906 had high selectivity to transplanted rice, but caused phytotoxic effect on direct-seeded rice when treated before 3-leaf stage. Herbicidal activity of KSC-13906 on the Echinochloa crus-galli var. oryzicola was 7-folds greater than that of pyrazosulfuron-ethyl in terms of relative dose ratio of the herbicides. These results suggest that KSC-13906 possesses selective herbicidal potency in rice.

• Korean Journal of Weed Science
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• v.6 no.2
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• pp.134-145
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• 1986

The experiment was crried out to evaluated the herbicidal properties of bensulfuron methyl [methyl 2-[[[[[(4, 6-dimethoxy pyrimidine-2yl) amino] carbonyl] amino] sulfonyl] methyl] benzoate]. No phytotoxicity was observed when bensulfuron methyl was applied at 3 and 6 g a.i./ 10a while the application rate 12 g a.i./10a slightly retared the growth of rice. The phytotoxicity decreased as the application time was delayed. The effect of application rate, leaching grade, transplanting depth, soil type and temperature on crop injury was little. Japonica variety (Dong-Jin) was more sensitive to bensulfuron methyl than indica X japonica variety (Sam-Kang). Bensulfuron methyl controlled effectively perennial weeds such as Sagittaria pygmaea Miq., Potamogeton diatinctus A. Benn., Cyperus serotinus Rottb., Sagittaria trifolia L., Eleocharis kuroguwai Ohwi. including most annual weeds except Echinochloa crus galli P. Beauv. The effect slightly decreased with lowering the temperature increasing the leaching grade. Application time and soil type employed did not affect the weeding effect.

• Korean Journal of Environmental Agriculture
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• v.22 no.1
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• pp.7-15
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• 2003

The characteristic of the quality of stream water and the riparian vegetation during rice cultivation in the rural area of the eastern Jeonnam province was surveyed from April to November, 2000. The water quality of the streams during rice cultivation was variable. The pH of these water bodies ranged from $6.5{\sim}8.3$. Electro conductivity (EC) at each water body ranged from $162{\sim}4,910\;{\mu}S/cm$ for Beogyo-cheoa $114.7{\sim}286.6\;{\mu}g/cm$ for Boseong-cheon, $74.8{\sim}147\;{\mu}S/cm$ for Songgwang-cheon, and $61.6{\sim}82.1\;{\mu}S/cm$ for Isa-cheon. Total nitrogen and other parameters (K, Ca, Mg, Na, $Cl^-$, SS) were higher at May (Boseong-cheon) through June (Songgwang-cheon, Isa-cheon) during the transplanting season than these same parameters at August October and November. Thirty weed species of sixteen families were found in the survey areas of Songgwang-cheon, Boseong-cheon Isa-cheon and Beolgyo-cheon. Nine annual weeds, four biennial weeds, and seventeen perennial weeds were found, several different life forms were identified. Of those species three were submerged, two were free floating, five were emerged, and twenty were water-side weeds.

• Korean Journal of Weed Science
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• v.10 no.4
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• pp.269-276
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• 1990

Weed species belonging to the broadleaf family prevailed in the experimental sites followed by Cyperucea and grass family. In terms of life cycle, the dominant weed species were the perennial weeds rather than annual weeds. Most of weeds were emerged between 30-60days after transplanting in Chuncheon and between 40-60 days after transplanting in Hongcheon and Hoengseong areas. Among agronomic characteristics of rice affected by weed emergence were decrease of plant height by 2-4㎝, panicle number by 1.3-2.9, spkelet by 3. 7-7.5, ripening rates by 3.3-6.5%, and milled yield by 12-17%.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.325-325
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• 2017

In the 20th century, the average temperature of Korea has risen by $1.5^{\circ}C$, whereas it has risen by $0.6^{\circ}C$ globally. Few studies have investigated the effect of seeding date in hilly pastures on their growth characteristics and productivity. The purpose of this study was to elucidate the effect of seeding dates at a hilly pasture establishment on its growth characteristics and productivity caused by increasing temperatures in Korea. The experiments were conducted from 2014 to 2016 at Pyeongchang, South Korea, at an altitude 600-700 m above sea level. The composition of grass mixture was tall fescue, orchard grass, perennial ryegrass, Kentucky bluegrass, timothy, and white clover. Treatments comprised four seeding dates (August 13 and 27, and September 10 and 24). The establishment rate was lowest on September 24, resulting in only 20% establishment over the winter, and the proportion of weeds was highest on September 24 (58%). Early seedling growth before overwintering is a critical approach to ensure successful establishment of grassland. The main components were orchard grass and tall fescue on the early seeding date (August 13), and Kentucky bluegrass on the late seeding date (September 24). Late seeding increased the proportion of bare lands invaded by weed species, especially during second and third cutting periods. Early seeding date resulted in a progressive increase in biomass. Total annual production was significantly affected by the seeding date; lowest dry matter production was on September 24 ($2,441kg\;ha^{-1}$), whereas maximum dry matter yield was on August 27 ($6,608kg\;ha^{-1}$). The results of the study indicate that growth condition and productivity could be increased by early seeding, and seeding of grass in the Pyeongchang area should be completed before August 27. However, further studies are needed to determine the ideal seeding date at the hilly pasture establishment in Pyeongchang.