• 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.

• 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%).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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• pp.32-37
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• 1999

The experiment was conducted to investigate emergence response of lowland weeds at different soil moisture contents, burying depths and upon changes in soil moisture. Rice germination was over 50% at all burying depths under aerobic condition, but the emergence rate of the soil surface placed seeds in saturated and flooded conditions decreased by 19% and 29%, respectively, as compared with that of aerobic condition. Rice seeds at burying depth of over 3 cm did not emerge at all. The emergence rate of Echinochloa crus­galli (L.) Beauv. in aerobic condition was lower than 30%, but the emergence pattern of E. crus galli (L.) Beauv. at different soil moisture contents and seeding depths was similar to that of rice. Emergence behavior of lschaemum rugosum Salisb., Ludwigia octovalvis (Jacq.) Raven and Sphenoclea zeylanica Gaertn. which are dominant lowland weed species in the Philippines also differed depending on soil moisture conditions and burying depths. lschaemum rugosum Salisb. emerged at all burying depths under aerobic condition, whereasLudwigia octovalvis (Jacq.) Raven emerged only at 0 cm deep under saturated and aerobic condition and Sphenoclea zeylanica Gaertn. at 0 cm deep under flooding condition. Weed seeds planted at 1, 3, and 5 cm deep in continuous flooded and saturated condition did not emerge at all, but upon a change of soil moisture condition from saturated to drainage (S$\rightarrow$D) and flooded to drainage (F$\rightarrow$D), grass weeds began to germinate again and the average emergence rate in S$\rightarrow$D and F$\rightarrow$D were 26% and 5% forE. crus­galIi (L.) Beauv., 9% and 8% forI. rugosum SaIisb., respectively. Weed seeds buried in soil in the pot showed great emergence at S$\rightarrow$D but did not emerge under continuous flooded condition. The diversity index accounting for dominance degree and occurrence aspect of weed, was the lowest at F$\rightarrow$D.

• Korean Journal of Plant Resources
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• v.32 no.5
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• pp.478-485
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• 2019

As environmentally sound agriculture emphasize gradually as well as the importance of environment, many studies on weed and soil nematode control of new concept which does not affect adversely environment are in progress. For this purpose, plant seeds which are representative weed species in field were selected and treated with microwave having generating capacity of $17.73kw/m^3$, and investigated germination rates of weed seeds and the number of soil nematode according to soil moisture contents, soil depth and irradiation times. The microwave effect on the germination rates was extremely high in soil moisture content of 40% and irradiation time over 40 seconds for irradiation time, while soil depth did not affect germination rate. In view of the results so far achieved, it seems that universal dispersed microwave system is effective for the control of weed seeds.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2009.04a
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• pp.146-148
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• 2009

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.3
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• pp.66-77
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• 1998

The purpose of this study is on identifying real condition of naturalized plants in urban green space. For this, Chollabak-do region was selected for case study. The occurring frequency and distribution status was investigated by field survey. The area of green open space, level of management and passed years after construction etc, were analized to identify the influence on occurrence of naturalized plants. The result is as follows: 1. In 18 sites, 145 taxa as weed species including naturalized plants were occurred. Average No. of occurring taxa is 22.7. Two families of plants, Graminae and compositae charged the most part. Also the rate of naturalized plant among them is 29.7%. 2. Naturalized species showing high occurring rate are 14 taxa of compositae, 5 taxa of Gramineae, Leguminosae and 4 taxa of cruciferae. These plants of previous four somatic polymorphism among all the naturalized plants. 3. The taxa number of naturalized plants were reducedby intensive management. But the rate of naturalized plants in extensively managed area was relatively lower than intensively managed one. Naturalizd plants were widely distributed in most of urban green space with being cognitioned as whole weed. 4. In origin of naturalized plants, the taxa from north America were 16 and the taxa from Europe were 16. Therefore the rate originated from north America and Europe charged high part as 68.2%. The rate of Annual, Biennial and Perennial were each 78.7%, 21.3%. The alternative of management for control aganist disturbance by Annual & Biennial required. 5. Multi-relations analysis shows 0.81 which is the relatively high interralation between the number of emerged axa and that of naturalized ones. 6. The number of naturalized species has no relation to the lapse of years after construction of open-space. Especially it was identified that weed control in the beginning of construction is very important. On the other hand the relation between Ys and Xp was Ys=1.784Xp+4.646.

• 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.4 no.3
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• pp.188-198
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• 2015

This study was conducted in order to investigate the distribution pattern of weeds and ecological characteristics on the dry field in the Eastern region of Korea. The weed species data were obtained from 12 regions in Gangwon-do and Gyeongsang-do. 150 taxa were recorded from three main distinguished habitats; inside of dry field (IDF), embankment around the end of dry field (EDF), levee slope of dry field (LS). The weed species of three different habitats were IDF 83 taxa, EDF 133 taxa and LS 105 taxa. The species showing higher rNCD value was Portulaca oleracea in IDF, Digitaria sanguinalis in EDF and Humulus japonicus in LS. Compositae was dominant family followed by Gramineae, Polygonaceae and Leguminosae. Life form was distinguished as Th-R5-D4-e and three different habitats showed the same results. Disturbance index was analysed as IDF 83.1%, EDF 68.4%, and LS 62.9%. Naturalized rate was analysed as IDF 28.9%, EDF 22.6%, and LS 20.0%. These results indicate that the weeding management, land use intensity, and human interference effect on the distribution index and naturalized rate of weed.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.405-412
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• 2015

Forty schools having natural turf playgrounds were investigated by on-spot investigation and oral interviews with relevant school officials to find out basic information on turfgrass management practices of school playgrounds in Gyeonggi province. Average area of playground was $3,890m^2$ per school and $12m^2$ per student. Ninety five percent of turf playgrounds were managed by school staff and ninety percent of schools spent less than 5 million won per year for turf management. The difficulties in turfgrass management were considered as a major challenge for the schools, followed by turfgrass management cost. Among the management practices, school officials pointed out weed management as the most difficult work, followed by irrigation. The average number of fertilization and mowing was 2 and 6 times per year, respectively. About the half of playgrounds were irrigated only when there was wilting symptom. Zoysiagrass was the most popular choice for the school playgrounds and only three school playgrounds were established with pop-up irrigation system. Fourteen school playgrounds had good turf quality but the rest of school playgrounds had inadequate turf quality requiring minor or full renovation.

• Asian-Australasian Journal of Animal Sciences
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• v.4 no.3
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• pp.245-250
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• 1991

Analysis of the characteristics and the grouping of the species of sown and weeds in artificial pastures was studied applying the principal component analysis method. Presency and coverage of six sown species and fifteen weed species which occurred in pastures of under-grazing and optimumgrazing were subject to analysis. From field survey, species were divided into three groups: the group A included five species such as Festuca arundinacea, Lolium perenne and Dactylis glomerata, etc., the group B included eleven species such as Polygonum longisetum, Agrostis alba and Rumex obtusifolius, etc., and the group C included five species such as Miscanthus sinensis, Rubus palmatus and Artemisia princeps, etc. The group A species corresponded to good pasture conditions and management. On the contrary, the group C species occurred in poor pasture conditions with inadequate management. The group B species corresponded to intermediate pasture conditions and management. Interrelated pair species co-existing and species non-co-existing were discovered. Factor loading as negative for the group A species. positive for the group C species and positive but lower than the group C species for the group B species. From these results it is concluded that the principal component analysis seems to one of the useful tools for the analysis of characteristics of species and the diagnosis of sown pasture vegetation, although further studies are required to get more general information about species characteristics.