• Korean Journal of Weed Science
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• v.32 no.2
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• pp.127-132
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• 2012

Field survey on the weed occurrence and the use of herbicides was carried out targeting 214 rice cultivating farmers at Gyeongsangbuk-do. 96.2% of farmers did machine planting in late May and this is 68.0% of total cultivating area. Spring plowing was first with 54.6%, followed by spring-fall and fall plowing with 24.8% and 15.0%, respectively. 75% of the farmers treated herbicide twice. 57.5% of them treated herbicide before transplanting and treated at post-emergence again. In case of only application, 84% of the farmers treated herbicide before transplanting. Twenty-three species were occurred at Gyeongsangbuk-do and Echinochloa spp. was the most dominant with 20.8%, Sagittaria trifolia was second with 10.4%, followed by Monochoria vaginalis and Sagittaria pygmaea with 9.9% and 9.7%, respectively. Sagittaria pygmaea was the most difficult to control followed by Echinochloa spp., M. vaginalis, and S. trifolia.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.34-39
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• 2000

A new fifteen 2,3-dihydro-2-ethyl-2,4,6,7-tetramethylbenzofuran-5-yl substituents in 5-benzofuryl-2-[1-(alkoxyimino)alkyl]-3-hydroxycyclohex-2-en-1-one derivatives as substrate were synthesized and their herbicidal activities against rice plant (Oryza sativa L.) and barnyard grass (Echinochloa crus-galli) with post emergence were measured under submerged conditions. The $R_{1}$=methyl substituents, $1{\sim}8$ showed the higher herbicidal activity to the rice plant and barnyard grass. The structure-activity relationships (SARs) on tile herbicidal activity of $R_{1}$ and $OR_{2}$ groups on the azomethine bond in substrates were analysized. From tile results of dicussed SAR, the herbicide activities against rice plant would depend largely on the steric factor, Whereas, in case of barnyard grass, the activities were governed by the hydrophobicity factor. The conditions of selective herbicide activity between the two plant species are assumed that the substrates should nave optimal hydrophobicity ( $(logP)_{opt.}=6.0$), a $R_{1}$ groups of small and a long $OR_{2}$ groups.

• Korean Journal of Environment and Ecology
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• v.20 no.3
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• pp.311-318
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• 2006

In an estuary, ecological dynamic is modified for a long time and memorized in soils and landscapes. As landscape memory, ecological motif is defined with dominance and rarity of vegetation. The purpose of the study is to investigate the existing vegetation character and to propose the ecological motif of this area. The present salt-water plants, community species composition and constancy degree around the estuary in Buandam watershed Buan-gun, Jeollabuk-do were analyzed. The results are as follows. The flora of the salt-water plants was listed as 16 taxa; 6 families,13 genera,14 species and 2 varieties. 5 taxa were Gramineae, 4 taxa Chenopodiaceae, and 4 taxa Comrositae. The salt-water plant communities are a total of 10 communities as listed; Zoysia sinica-Artemisia scoparia community, Phacelurus latifolius community, Artemisia scoparia Cnidium japonicum community, Limonium tetragonum -Artemisia scoparia community, Artemisia scoparia community, Suaeda japonica community, Elymus dahuricus community, Suaeda asparagoides community, Zoysia sinica community, and Zoysia sinica-Suaeda japonica community. Analyzed by the community classification species class of constancy degree, Phacelurus latifolius, Cnidium japonicum, Limonium tetragonum, Suaeda japonica, Elymus dahuricus and Suaeda asparagoides belong to I, Zoysia sinica and Artemisia scoparia to II. Elymus dahuricus, Setaria viridis var. pachystachys, Echinochloa crusgalli var. oryzicola, Phacelurus latifolius, Atriplex gmelini, Salicornia herbacea, Calystegia soldanella and Aster tripolium belong to the accompaniment species to I: Zoysia sinica, Suaeda asparagoides, Artemisia capillaris to II; Suaeda japonica, Artemisia scoparia to III ; Cnidium japonicum to IV: Limonium tetragonum, Artemisia fukudo to V. And the ecological motif is the Phacelurus latifolius community.

• 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.

• Weed & Turfgrass Science
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• v.2 no.4
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• pp.413-420
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• 2013

The climate change affects the growth and development of weeds as well as the outbreak of weeds. Especially, the occurrences of problematic paddy weeds due to climate change might cause the difficulties in weed control. This study therefore, investigated the current dominance and distribution of paddy weeds. As a result of the study on paddy weeds in northern Gyeonggi-do, there were total of 65 taxonomy groups including 23 family, 41 genus, 57 species, 7 subspecies and 1 variety. Among all the plants, 46 species were annual plants and 16 were perennial plants. Echinochloa crus-galli was the highest in importance analysis and the followings were in order of Ludwigia prostrate and Lemna paucicostata. The similarity of different paddy weeds in different regions observed through TWINSPAN analysis was distinguished by Fimbristylis miliacea, Rotala indica and Cyperus flaccidus. Regional differences shown in CCA analysis using weed species and soil environment revealed that Gimpo-si and Namyangju-si has difference soil and weeds, which are features that distinguished them from other regions. In northern Gyeonggi-do the result of paddy weed research showed the interregional difference not in dominant weeds but in distribution species.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.690-706
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• 2019

Paddy fields play an important role in the biodiversity conservation of agroecosystems as man-made wetlands. This study focused on the floristic composition and characteristics of paddy fields in South Korea. The flora surveys were conducted in 33 areas in nine provinces at two times (June and August) in 2016. The results showed that the vascular plants of the paddy fields in South Korea included 389 taxa, composed of 51 families, 219 genera, 350 species, four subspecies, 30 varieties, and five forms. Among the 51 families, Gramineae was the most diverse in species (76 taxa), followed by Compositae (61 taxa), Leguminosae (32 taxa), Cyperaceae (27 taxa), Polygonaceae (15 taxa), and Scrophulariaceae (12 taxa). Based on the occurrence frequency of each species, Digitaria ciliaris (Retz.) Koel. (100%), and Echinochloa crus-galli (L.) P.Beauv. (100%) were the highest, followed by Acalypha australis L. (97.0%), Bidens frondosa L. (97.0%), Alopecurus aequalis Sobol. (97.0%), Rorippa palustris (Leyss.) Besser (93.9%), Ludwigia prostrata Roxb. (93.9%), Lemna perpusilla Torr. (93.9%), Mazus pumilus (Burm. f.) Steenis(90.9%), Rorippa palustris(Leyss.) Besser(87.9%), Eclipta prostrata(L.) L.(87.9%), Commelina communis L.(87.9%), Artemisia princeps Pamp.(84.8%), Erigeron annuus (L.) Pers.(84.8%), Cyperus microiria Steud.(84.8%), and Aneilema keisak(Hassk.) Hand.-Mazz. (81.8%). The biological type of paddy fields in South Korea was determined to be Th-R₅-D₄-t type. Rare plants were found in six taxa: Aristolochina contorta Bunge, Penthorum chinense Pursh, Sagittaria sagittifolia subsp. leucopetala (Miq.) Hartog, Ottelia alismoides (L.) Pers., Pseudoraphis ukishiba Ohwi, and Acorus calamus L. Eighty taxa contained naturalized plants composed of 15 families, 54 genera, 76 species, three varieties, and one form. The urbanization and naturalization indices were 24.8% and 20.6%, respectively.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.447-466
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• 2019

The orchard flora where perennial fruit trees are grown may be different than in arable fields where annual crops are grown. The study focused on the floristic composition and characteristics of orchards in South Korea. The flora surveys were conducted in 36 areas in nine provinces at two times (May-June and August-September) in 2014. The results showed that the vascular orchard plants in South Korea included 466 taxa, which contained 91 families, 278 genera, 420 species, two subspecies, 39 varieties, four forms, and one hybrid. Among the 91 families, Compositae was the most diverse in species (66 taxa), followed by Gramineae (51 taxa), Leguminosae (28 taxa), Cyperaceae (18 taxa), Polygonaceae (17 taxa), Cruciferae (16 taxa), and Labiatae (14 taxa). Based on the occurrence frequency of each species, Digitaria ciliaris (Retz.) Koel. (100%) was the highest, followed by Acalypha australis L. (94.4%), Commelina communis L. (94.4%), Persicaria longiseta(Bruijn) Kitag.(91.7), Capsella bursa-pastoris(L.) L. W. Medicus(91.7%), Erigeron annuus (L.) Pers. (91.7%), Mazus pumilus (Burm. f.) Steenis (86.1%), Artemisia princeps Pamp. (86.1%), Cyperus microiria Steud. (86.1%), Stellaria aquatica (L.) Scop. (83.3%), Stellaria media(L.) Vill.(83.3%), and Echinochloa crus-galli (L.) P. Beauv.(83.3%). The biological type of orchards in South Korea was determined to be Th-₅-D₄-e type. Rare plants were found six taxa: Cinnamomum camphora (L.) J. Presl, Aristolochia contorta Bunge, Melothria japonica (Thunb.) Maxim., Ardisia crenata Sims, Gnaphalium hypoleucum DC., and Aster koraiensis Nakai. Eighty-five taxa contained naturalized plants composed of 23 families, 58 genera, 80 species, four varieties, and one form. The urbanization and naturalization indices were 26.3% and 18.2%, respectively.

• Weed & Turfgrass Science
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• v.5 no.2
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• pp.71-81
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• 2016

This study was conducted to investigate the weed occurrence and distribution on the orchard fields (apple, pear, peach, grape) at 387 sites in Chungbuk province of Korea from May to September in 2015. From the result of this survey, 200 weed species in 47 families were identified and classified to 82 annuals, 40 biennials and 78 perennials. Based on the occurrence ratio, the most dominant weed species in Chungbuk province orchard fields were higher in order of Digitaria ciliaris (4.12%), Echinochloa crus-galli (3.60%), Stellaria aquatica (3.45%), Artemisia princeps (3.07%) and Chenopodium album (3.06%). The composition of major occurred weed families, Compositae, Poaceae, Leguminosae and Cyperaceae were 21, 9, 6 and 6%, respectively. Coefficient of similarity between a various orchards based on the degree of dominance were ranged from 68.7-91.8%. The most important weed species at apple, peach, grape was Digitaria ciliaris while these for pear was Poa annua. Fifty-one exotic weed species were also identified. The results of this study could be useful information for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods on the orchard fields in Chungbuk province of Korea.

• Korean Journal of Weed Science
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• v.12 no.2
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• pp.173-182
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• 1992

Regardless of the test species, germination was adversely affected by the different concentrations of the acidic and neutral fractions of sunflower root exudates while the basic and aqueous fractions had no effect on germination. In both test species, root lengths were inhibited slightly more than shoot lengths. Significant reduction in fresh weights of the test species was observed when the test species were treated with the acidic and neutral fractions but not with the basic and aqueous fractions. Six compounds, hydroquinone, ${\beta}$-resorcyclic acid, vanillic acid, caffeic acid, salicylic acid, and quercetin, were characterized from the acidic fraction. Seven compounds, hydroquinone, gentisic acid, ${\beta}$-resorcyclic acid, vanillic acid, caffeic acid, ferulic acid, and quercetin, were elucidated from the neutral fraction.

• FLOWER RESEARCH JOURNAL
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• v.16 no.4
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• pp.266-274
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• 2008

Korean native plants were investigated for their suitability to be used for floral clusters after drying. Floral clusters which were made in semi-sphere with a hand-tied method and can be fit in $22{\times}22{\times}37cm$ paper boxes were made with 37 species. Among 37 species, the 14 species which were easy to dry, to make floral clusters, and have not been used in other countries, were Echinochloa crus-galli var. frumentacea, Imperata cylindrica var. koenigii, Muhlenbergia huegelii, Phleum pratense, Setaria glauca, and Setaria viridis in Gramineae, Artemisia capillaris, Artemisia montana, and Chrysanthemum indicum in Compositae, Agastache rugosa, Elsholtzia ciliata, Elsholtzia splendens in Labiatae, Carex neurocarpa in Cyperaceae, and Vitex rotundifolia in Verbenaceae were used with leaves, flowers, and fruits. The suitable plants for a floral cluster in $22{\times}22{\times}37cm$ paper box, a wreath in $22{\times}22{\times}6cm$ paper box, and a flower arrangement in $22{\times}22{\times}22cm$ paper box, which were made to a set, were 10 species, that is Phragmites communis, Setaria glauca, Setaria viridis, Artemisia capillaris, Artemisia montana, Chrysanthemum indicum, Elsholtzia ciliata, Elsholtzia splendens, Mosla punctulata, and Vitex rotundifolia.