• Korean Journal of Medicinal Crop Science
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• v.7 no.2
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• pp.121-128
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• 1999

This experiment was carried out to establish effective weed control system in the cultivation of Coix lachryma-jobi L. The effect of annual weeds artificially transplanted on the growth of Coix lachryma-jobi L. were that the higher the density of weeds, the lower the yield considerably by reducing number of grains and tillers per plant. Among four weeds of Echinochloa crusgalli galli P. BEAUV., Digitaria sanguinalis $S_{COPOL}$., Chenopodium album L., and Portulaca oleracea L., weed of Portulaca oleracea L. reduced adlay yield most by 182.6kg/10a and it was judged to be the most injurious weed to adlay production. Among four weed control systems, which are one herbicide treatment, one herbicide treatment + one cultivating work with cultivator, two times cultivating work with cultivator and two times hand-weeding, the control system of 'one herbicide treatment + one cultivating work with cultivator' showed the lowest amount of weed growth by 7.34 weeds per $m^2$ in comparison with control plot of 35.00 weeds per $m^2$. Among four weed control systems, the system of 'two times hand-weeding' had much more amount of light penetration in adlay canopy with 791.9 mol than any other systems.

• Korean Journal of Weed Science
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• v.1 no.1
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• pp.44-51
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• 1981

An experiment was conducted to obtain the basic information about competitive ability of rice against weeds as affected by culm length at the Yeongnam Crop Experiment Station, Office of Rural Development in 1980. More weeds were harvested from the plot of short statured cultivar, Manseogbyeo compared to the plot of Cheongcheongbyeo that was approximately 10cm taller than Manseogbyeo regardless of planting density variables. Weeds also decreased as rice population increased from $30{\times}15cm$, $40{\times}(10{\times}10cm)$ and to $10{\times}10cm$, in order. The degree of weed suppression and floristic composition was varied depending upon plant spacing and weeding regime subjected at the previous year. The degree of weed suppression became increased with increasing rice population. The degree of weed suppression at the $10{\times}10cm$ plant spacing showed as high as hand weeding subjected in the previous year. However, in terms of floristic composition, Scirpus hotarui Roxb. became dominant when rice had cultivated at $10{\times}10cm$ plant spacing in the previous year while S. hotarui and Sagittaria pygmaea Miq. were both important in the hand weeding plot. The highest grain yield of rice showed at the $10{\times}10cm$ plant spacing while no significant difference was observed between $40{\times}(10{\times}10cm)$ and $30{\times}15cm$ plant spacings for both weeding regimes and both cultivars. However, response of grain yield to weeding regime was differed in two cultivars. For Manseobgyeo, significant grain yield decreased in no weeding plot regardless of plant spacing variables. But in case of Cheongcheongbyeo, grain yield reduction was only recognized at the $30{\times}15cm$ plant spacing. Based on these result it could be concluded that Cheongcheongbyeo (10cm taller in height) seemed to be more competitive against weeds than Manseogbyeo.

• Korean Journal of Weed Science
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• v.31 no.3
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• pp.279-288
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• 2011

To suggest the weed management technique for environment friendly rice cultivation, we investigated occurrence patterns of weeds, the actual condition of weed management, and rice yield at the environment friendly agricultural complex located in Honam and Chungnam regions. The practical performance of weed management was relatively satisfactory in decreasing order of agricultural technique with golden-apple-snail (GAS) > agricultural technique with duck (Duck) > agricultural technique with rice bran (RB) > agricultural technique with soft-shelled turtle (ST). In the rice fields employed by agricultural technique with GAS, the dominant weeds were Echinochloa crus-galli, Ludwigia prostrata, Monochoria vaginalis, Sagittaria trifolia, and Aneilema keisak. However, E. crus-galli, M. vaginalis, L. prostrata, Aeschynomene indica and Bidens frondosa were found as dominant weeds at the fields using the Duck and E. crus-galli, M. vaginalis, L. prostrata, Polyganum hydropiper and Eleocharis kuroguwai at the fields using RB. In comparison of rice yield ($5.2\;MT\;ha^{-1}$) obtained from the conventional cultivation using herbicides, about 93% was reached by Duck, about 91% by GAS, about 92% by RB, and about 78% by ST. When rice qualities obtained from environment friendly rice cultivation were compared with those from the conventional cultivation, the producing rates of perfect kernel, immature kernel, immature opaque kernel, cracked rice, and damaged kernel were lower in the former cultivation, whereas contents of protein, amylose, and fatty acid were similar in the two cultivation methods. The problems found in the environment friendly agriculture were poor plowing and harrowing, carless irrigation management, and geological poor condition as cultivation area with cold water. These have caused severe infestation of weeds, frequent incident of disease and insect pest, and rice lodging. This resulted in reduction of rice yield as high as about 32 to 79% as compared with the conventional cultivation using herbicides.

• Weed & Turfgrass Science
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• v.3 no.2
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• pp.78-85
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• 2014

The survey of weed occurrence was conducted to identify dominant weed species in the paddy field. Total 346 sites of the 12 regions in Chungbuk Province in Korea were investigated in July, 2013. Weed flora was composed of 43 species belonged to 15 families. The compositions of major plant families, Cyperaces, Poaceae, Pontederiaceae and Asteraceae, were 21.5, 17.4, 15.5 and 12.7%, respectively. Based on life cycle, weed species was grouped into annuals of 71.3 and perennials of 28.1%. The most dominant weed species in paddy fields of Chungbuk Province were Monochoria vaginalis (14.5%), followed by Scirpus juncoides (10.5%), Echinochloa oryzoides (9.3%), Eleocharis kuroguwai (7.0%), Aeschynomene indica (6.2%) et al. The similarity of paddy weeds in 12 regions observed through TWINSPAN analysis was distinguished by Persicaria longiseta, Aneilema keisak, Persicaria thunbergii, Fimbristylis millacea, Blyxa japonica, Digitaria ciliaris, Potamogeton distinctus, Cyperus nipponicus. This information could be useful for estimation of future weed occurrence and establishment of weed control methods in chungbuk province in Korea.

• 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.

• Korean Journal of Weed Science
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• v.3 no.2
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• pp.120-128
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• 1983

The nationwide survey of weed population covering 1,800 wheat and barley fields in 60 Cities and Guns all around Korea was conducted in December of 1982 and March-April of 1983. In this survey result, two species of gresses and 35 species of broadleaves were identified, and among them 36 and 29 species were found in the wheat and barley fields of upland and paddy, respectively. In the scope of weed life cycle, biennials were more dominant than perennials and annuals in these fields. The most dominant weed species in upland fields were Stellaria media, Cyrillus and Alopecurus aequalis Sobol var. amurensis Ohwi while those in paddy fields were Stellaria alsine Grimm. var. undulata Ohwi and Alopecurus aequalis Sobol var. amurensis Ohwi. In addition, the more weeds were observed in the conventional row seeding method than in other seeding methods including drill seeding and also in no-tillage than in tillage method. In the other hand, the successive use of herbicide for several years greatly influenced the pattern of weed occurrence; broadleaved weeds increased and grasses decreased with the successive use of herbicides.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.295-307
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• 2015

Surveys of weed species in paddy fields were conducted to identify weed occurrence on July 2013. Total 237 sites of paddy fields in 9 City/Gun, Jeonnam Provinces in Korea were investigated. From the survey, 45 weed species in 18 families were identified and classified to 33 annuals and 15 perennials. Based on the occurrence ratio, the most weed species belonged to Poaceae (9 species) and 8 and 4 weed species belonged to Cyperaceae and Scrophulariaceae, respectively. These 21 weed species in the most four families accounted for 46% of total weed occurrence. The most dominant weed species in Korean paddy fields were Echinochloa spp. (18.5%), followed by Monochoria vaginalis (12.3%), Lemna perpusilla (8.2), Eleocharis kuroguwai (5.2%) and Scirpus juncoides (5.2%). The most dominant weed species in machine transplanting paddy fields were Echinochloa spp. (14%), followed by Monochoria vaginalis (12%) and in water seeded rice paddy fields were Echinochloa spp. (25%), followed by Monochoria vaginalis (11%). This information could be useful for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods in paddy fields.

• Korean Journal of Weed Science
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• v.13 no.1
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• pp.26-35
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• 1993

Differences in weed occurrence was investigated among five types of rice (Oryza sativa L.) cultivation. The five types employed were three transplanting cultivations such as conventional hand transplanting, machine transplanting with 30-day-old seedling, and machine transplanting with 10-day-old seedling and two direct-seedings such as flood direct-seeded rice by pregerminated seed and dry direct-seeded rice by dry seed. Weed specie, occurred varied from 7 to 20, depending on the different cultivation types. Weeds were more diverse in transplanting with l0-day-old seedling than in other transplanting cultivations and in direct-seeding than in transplanting practice. Dominant weed species also varied with cultivation types. In transplanting cultivations Scirpus juncoides Roxb., Echinochloa crus-galli (L.) P. Beauv., and Eleocharis kuroguwai Ohwi were dominant, whereas occurrence of annual weeds such as Cyperus difformis L. and Monochoria vaginalis Presl. aside from the three weed species increased in direct-seeded cultivations.

• Weed & Turfgrass Science
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• v.5 no.3
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• pp.177-180
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• 2016

This study was conducted to identify problematic weed species in grape orchard fields to establish basic information for suitable weed control. Surveys of weed species occurring in grape orchards were conducted in Chungnam province including Daejeon and Sejong of Korea from April to June and from September to October in 2015. From the surveys, 50 weed species belonging to 23 families (33 annuals and 17 perennials) were identified. In the first survey, the most dominant weed species by the importance values was Poa annua (7.07) followed by Echinochloa crus-galli (6.56), Digitaria ciliaris (6.43) and Capsella bursapastoris (5.63). In the second survey, Rorippa palustris (9.59), Eclipta alba (9.13), Digitaria ciliaris (7.68) and Poa annua (7.68) were dominant. Different weed species and dominance patterns were detected according to weed control methods in the grape orchards. Seven weed species belonging to six families were identified in the field in which herbicides were being used as a weed control method. However, most weed species (21 species belonging to 9 families) were occurred in the mowing + tillage fields. These surveys provide information about seasonal variations of weeds species occurred in grape orchards and impact of different weed control methods on the weed occurrence.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.1
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• pp.73-78
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• 2017

This study was conducted to elucidate the effects of mulching materials on root growth characteristics and weed occurrence of Platycodon grandiflorum transplants (3 years old) in organic farming. After transplanting, roots were mulched with one of three mulching materials (biodegradable film, sawdust, or rice husks) or a control (no mulching). The average root diameter of all mulching groups was 28.1 mm, which was 5.1 mm thicker than the no-mulching treatment. Roots with the biodegradable film treatment were the thickest at 30.9 mm. Root length was the shortest, 22.0 cm, with rice husk mulching. The number of rootlets was the highest with film mulching (36.0 rootlets/root) and the lowest with no mulching. For root fresh weight, which directly affects yield, the average of treated and untreated roots was 100 and 56 g/root, respectively. The highest fresh weight was in the biodegradable film plot (130 g/root). The mulching treatment groups showed a weed inhibition effect compared with the no-mulching treatment. The dominant weeds with the no-mulching treatment were Setaria viridis and Digitaria ciliaris, and that with the mulching treatment was Setaria viridis. Average annual weed occurrence across all treatments was 72%. Weed occurrence was the highest with the no-mulching treatment ($125weeds/m^2$), and there were no weeds with the biodegradable film treatment.