• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.310-318
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• 1983

Four methods of vegetation analysis were compared to determine the most suitable method to use in transplanted rice. The highest number of weed species, 14 was obtained with the list quadrat method while the least number, 8 was obtained with the line intercept method. The clip quadrat method tended to overestimate weed species with a low moisture content such as Sagittaria trifolia L. and Ludwigia prostrata Roxb while for the list quadrat method, weed species with a high moisture content such as Sagittaria pygmaea Miq. and Monochoria vaginalis (Burm. f) Pres 1 were overestimated. With the line intercept method, weed species having conspicuous leaf blades such as S. trifolia and Potamogeton distinctus Benn. were dominant. Of the methods tested, the line intercept method was the least desirable because it accounted for the least number of weed species. Any of the others could be use for vegetation analysis without any significant problems arising. However, preference was given to the point quadrat method because of the ease of measurement. It was also less tedious and less time consuming than the other methods.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.59-67
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• 2010

The distribution of exotic weeds in 4 island area such as Baengnyeong-do, Heuksan-do, Chuja-do, and Geomun-do in Korea was investigated. Baengnyeong-do, Heuksan-do, Chuja-do, and Geomun-do have different weed flora, 41 species included 13 families, 32 species included 11 families, 23 species included 9 families and 30 species included 12 families were observed in the 4 islands, respectively. 18 families 70 species were occurred in 4 island. Most troublesome exotic weeds were Ambrosia artemisiifolia var. elatior, Solanum carolinense, Cuscuta pentagona. Occurrence frequency of Conyza canadensis, Erigeron annuus, Dactylis glomerata, Bromus catharticus and Lolium multiflorum were the highest in each island, respectively. Also, result of divided life cycle, annual weeds were 28 species occupied 40% in total, biennial weeds were 21 species (30%) and perennial weeds were 21 species (30%).

• Korean Journal of Weed Science
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• v.8 no.2
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• pp.133-140
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• 1988

One hundred and one noxious weeds on cultivated land of Taiwan were investigated for the occurrence of "Kranz" leaf anatomy and activities of PEP carboxylase and $C_4$ acid decarboxylating enzymes : NADP-malic enzyme, NAD-malic enzyme, PEP carboxykinase. Based on the leaf anatomy and a/b chlorophyll ratio, twenty-seven species exhibit "Kranz" type leaf anatomy, and seventy-four species were found without it. Among the species investigated, Digitaria radicosa (Presl) Miq., Leptochloa chinensis (L.) Nees, and Sporobolus fertilis (Steud.) W. D. Clayton in the Gramineae were first recorded as $C_4$ plants. Twenty-sven species of "Kranz" type leaf anatomy, include those of monocotyledon ; sixteen species in Gramineae, six species in Cyperaceae. Those of dicotyledon ; two species each in Euphorbiaceae and Amaranthaceae and one species in Portulacaceae. The subtype of fourteen previously uninvestigated species among twenty-seven species were further determined. The properties of the three decarboxylating enzyme from representative species were also characterized.

• Korean Journal of Weed Science
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• v.15 no.4
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• pp.305-312
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• 1995

Weed communities in the dry-direct seeded rice(Oryza sativa L.), soybean(Glycine max(L.) Merr.), and dry-direct seeded rice-soybean rotation system from the transplanted rice field were investigated in order to identify a change in weed species by paddy-upland rotation. Echinochloa species was the most dominant species in the dry-direct seeded rice and their great increase was observed in the continued practices of dry-direct seeded rice. Echinochloa spp., Chenopodium ficifolium, and Digitaria spp. were identified as the major weeds in soybean cultivation in paddy field. Practice of soybean rotation in the dry-seeded rice reduced weed occurrence, particularly at the soybean after 2-yr continued dry-direct seeded rice and at dry-direct seeded rice culture after 2-yr continued dry-direct seeded rice and at dry-direct seeded rice culture after 2-yr soybean compared to the continued cultures of rice or soybean. In addition, cultivation of dry-direct seeded rice or soybean culture in the paddy rice field seemed to be helpful for suppression of perennial weeds(Eleocharis kuroguwai, Cyperus serotinus, Scirpus juncoides) and aquatic weeds(Monochoria vaginalis, Sagittaria spp. Potamogeton distinctus).

• Journal of Crop Science and Biotechnology
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• v.10 no.2
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• pp.79-85
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• 2007

Rice bran application just after transplanting has been increasingly practiced as an herbicide-substitute for organic rice production in Korea. However, this practice is frequently reported to be unsatisfactory in weed suppression. An experiment with five treatments that combines flooding depth, rice bran application dose, and herbicide treatment was done in the paddy field to evaluate whether rice bran application under deep flooding can lead to a successful weed control in compensation for the single practice of rice bran application. Rice bran was broadcasted on the flood water surface just after deep flooding of 8 to 10cm that was started at seven days after transplanting. In the shallow flooding plot without herbicide six weed species were recorded: Monochoria vaginalis, Echinochloa crus-galli, Ludvigia prostrate, Cyperus amuricus, Aneima keisak, and Bidens tripartite. Among the first four dominant weed species, deep flooding significantly suppressed the occurrence of Echinochloa crus-galli and Cyperus amuricus while did not suppress the occurrence of Monochoria vaginalis and Ludwigia prostrate. On the contrary, rice bran application under deep flooding suppressed significantly Monochoria vaginalis and Ludwigia prostrate while didn't exert an additional suppression of Echinochloa crus-galli and Cyperus amuricus compared to deep flooding alone. Rice bran application and deep flooding suppressed complimentarily all the six weed species to a satisfactory extent except for Monochoria vaginalis of which suppression efficacy was 31.9%. Deep flooding reduced the panicle number substantially by inhibiting the tiller production, increased the spikelet number per panicle slightly, and leaded to a lower rice grain yield compared to shallow flooding with herbicide. Rice bran application under deep flooding mitigated the panicle reduction due to deep flooding, increased the spikelets per panicle significantly, and thus produced even higher grain yield in the rice bran application of 2000kg $ha^{-1}$ as compared to the shallow flooding treatment with herbicide. In conclusion, this practice applying rice bran under deep flooding would be promising to be incorporated as an integral practice for an organic rice farming system.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.4-10
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• 1984

This experiment was conducted to determine the change in weed flora with season and cultivated crop and land. There are 44 species in 38 genera and 18 families, consisting of 22 annual, 11 biennial and 9 perennial weeds in uplands in Jeonbug Province. Digitaria sanguinalis Scopol. occurred with the highest frequency of 67.2% and in decreasing order Portulaca oleracea L., Chenopodium album L. and Erigeron canadensis L. followed. About 60% of total sites studied indicated Simpson`s index ranging from 0.20 to 0.50. The Simpson`s index decreased from 0.65 on June 8 to 0.15 on November 10. Dominant weed species were Alopecurus aequalis Sosbol, and Polygonum hydropiper Spach in double cropping paddy field, but D. sanguinalis and P. oleracea were the dominant species in uplands. In reclaimed uplands various weed species including, 4rtemisia asiatica Nakai occurred almost equally. Average Simpson`s index for six crops studied was 0.40 and irrespective of the crops being cultivated P. oleracea and D. sanguinalis were dominant weed species and Y. hydropiper, C. album, Exolus blitum Grenier and E. canadensis were sub-dominant.

• 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.

• Weed & Turfgrass Science
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• v.3 no.2
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• pp.95-101
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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 Ligularia fischeri fields. Survey was carried out five times, on May, June, July, August and October in 2013. The weed flora was composed of a total of 104 weeds, 37 families, of which 55 species were annual, 25 species were biennial, and 24 were perennial plants. Twenty-six exotic species were included as well. Dominance was the highest with Chenopodium album followed by Stellaria aquatica, Echiochloa crus-galli, Conyza canadensis, and Artemisia princeps etc. in order. In the PCA plot analysis, weeds occurred in cultivated L. fischeri fields were divided into three groups, Persicaria thunbergii-Bidens frondosa community, Chenopodium album community and Capsella bursapastoris community. The degree of damages in cultivated L. fischeri fields was investigated by weighing roots of L. fischeri. We found that 56% decreased root weight in no weeding plots comparing to that in weed management plots. We infer from this result that decreased roots will affect to the growing of L. fischeri in following year.

• Journal of Forest and Environmental Science
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• v.20 no.1
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• pp.82-92
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• 2004

Farm working also needs most of the labor on the weed management of the levee. Then, the research which controlled the weed in the weed was promoted in order to reduce this weed management. Required conditions for the levee vegetation from the viewpoint of the weed management are the following 4 points. (1) the prevention of erosion and landslide, (2) the improvement in the workability at the mowing, (3) the improvement and maintenance of the rural landscape, (4) the accessibility. Next, the plants becoming dominant species in devastated land and slope of river banks were compared through these 4 conditions, and the utility was examined. As the result, Imperata cylindrica Beauv., Shibataea kumasaca Nakai, Sasaella kogasensis Nakai var. gracillima S. Suzuki and Hedera canariensis Willd, seemed to be usable. Finally, weed management method for connecting for the reduction in the mowing work using these plants was presented.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.308-321
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• 2010

To increase of weed researches, abbreviations for Korean weeds name(tentatively named 'KSWS code', the Korean Society Weed Science code) of 433 species belonging to 68 families in arable land were suggested in this paper. The KSWS code was derived from Bayer code or/and modified. The KSWS code was composed of alphabetic 5 characters, namely 3 characters in generic name and 2 characters in specific name. And variable species's KSWS code was 1 characters in generic name and 1 characters in variable name.