• Journal of Ecology and Environment
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• v.30 no.3
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• pp.209-223
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• 2007

Twenty-four wetlands located in Higashi-Hiroshima City in West Japan were selected for this study in order to investigate both the relationship between aquatic plant composition and environmental conditions; and the relationship between changing land use patterns in the catchments and the concentration of different forms of nitrogen in the wetlands. The dominant and subdominant species which comprised the principal vegetation were determined based on a vegetation census conducted in each wetland during the growing season from June to August, 2006. The seasonal variations of water quality factors (pH, electrical conductivity, turbidity, dissolved oxygen, total dissolved solid, and temperature) and different forms of nitrogen such as nitrite, nitrate, ammonium, total nitrogen, dissolved organic nitrogen and dissolved inorganic nitrogen concentrations were analyzed as important indicators of water quality for the surface water of the wetlands. The surveyed wetlands were classified into three types (non-disturbed wetlands, moderately-disturbed wetlands and highly-disturbed wetlands), based on the degree of human disturbance to their catchment areas. An analysis of variance indicated that there was a significant difference among the wetland groups in the annual mean values of electrical conductivity, total dissolved solids, total nitrogen, nitrite, dissolved inorganic nitrogen and dissolved organic nitrogen. Classification of the wetlands into three groups has revealed a pattern of changes in the composition of plant species in the wetlands and a pattern of changes in nitrogen concentrations. A majority of the non-disturbed wetlands were characterized by Brasenia schrebi and Trapa bispinosa as dominant; with Potamogeton fryeri and Iris pesudacorus as sub-dominant species. For most of the moderately-disturbed wetlands, Brasenia schrebi were shown to be a dominant species; Elocheriss kuriguwai and Phragmites australis were observed as sub-dominant species. For a majority of the highly-disturbed wetlands, Typha latifolia and T. angustifolia were observed as dominant species, and Nymphea tetragona as the sub-dominant species in the study area. An analysis of land use and water quality factors indicated that forest area played a considerable role in reducing the concentration of nutrients, and can act as a sink for surface/subsurface nutrient inputs flowing into wetland water, anchor the soil, and lower erosion rates into wetlands.

• Korean Journal of Environment and Ecology
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• v.29 no.2
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• pp.105-131
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• 2015

This study was carried out to investigate the flora of Gyodongdo island (Ganghwa-gun). The vascular plants from 11 field surveys were revealed to belong to a total of 629 taxa; 118 families, 364 genera, 561 species, 5 subspecies, 53 varieties, 7 forms and 3 hybrids. 184 taxa were the first records from this region. The plants in Gyodongdo island are composed of the deciduous broad-leaved and conifer-mixed forests which are the common ones in the middle part of the Korean Peninsula. Five taxa of Korean endemic plants such as Clematis brachyura Maxim., Viola seoulensis Nakai, Populus ${\times}$ tomentiglandulosa T. B. Lee, Forsythia koreana (Rehder) Nakai and Hemerocallis hakuunensis Nakai were collected. Endangered wild plants designated by the law called 'Protection Law for Endangered wild fauna and flora' were one taxon. The red list plants according to IUCN valuation basis were examined for 13 taxa; endangered (EN) species of Prunus yedoensis Matsum., Vulnerable (VU) species of both Utricularia pilosa (Makino) Makino and Iris ruthenica var. nana Maxim., Near Threatened (NT) species of Senecio argunensis Turcz., Least Concern (LC) species of Platycladus orientalis (L.) Franco, Potentilla discolor Bunge, Limnophila sessiliflora (Vahl) Blume, Acorus calamus L., Phacelurus latifolius (Steud.) Ohwi, Pseudoraphis ukishiba Ohwi, Belamcanda chinensis (L.) DC., and Not Evaluate (NE) species of both Astragalus sikokianus Nakai and Potamogeton oxyphyllus Miq. The floristic regional indicator plants found in this area were a total of 47 taxa comprising three taxa of grade V, four taxa of grade IV, nine taxa of grade III, 10 taxa of grade II, and 21 taxa of grade I. The naturalized plants were identified as 62 taxa and the percentage of naturalized index (NI) was 9.9 % and the percentage of urbanization index (UI) was 19.3 %, respectively. Furthermore, hemicryptophytes (28 %), therophytes (26 %), hydrophytes (13 %) and geophyte (12 %) showed high proportional ratio in life form spectrum.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.1
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• pp.24-34
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• 1976

The most troublesome perennials in the paddy fields in Korea, such as Cyperus serotinus, Potamogeton Franchetii, Sagittaria pygmaea and Eleocharis Kuroguwai, were studied about shape, aspects of ,germination, depth of development(under flooded and upland conditions), reproduction process and production amount. And these characters were compared with in these perennials.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.39-51
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• 1984

Effects of major phenolic acids identified from barley residues (straw, root) on the germination of rice and 3 paddy weeds such as Echinochloa crusgalli, Cyperus serotinus, and Potamogeton distintus were evaluated to obtain the basic informations on the development of naturally occurring herbicides. The predominant phenolic compounds extracted from barley residues in both straw and root were identified as p-coumaric, p-hydroxybenzoic, ferulic, vanillic, and salicylic acids by means of paper chromatography. Total phenol content of barley straw and root at the harvesting stage was 0.169% and 0.127% per dry weight, respectively. During the decomposing process, total phenol content slightly increased and then decreased. The germination of test plants was inhibited by treatments of 4 major authentic phenolic acids identified, most significantly on rice, and less on E. crusgalli, and C. serotinus. P. distintus, however, was markedly stimulated by them as the concentration increased, and then sprouted buds of pondweeds were changed to dark brownish color, resulting in the death as the treatment prolonged. The greater inhibitory effect appeared on shoot growth rather than germination. The aqueous extracts of barley residues showed the similar inhibitory effect on the germination and shoot growth of rice and three paddy weeds as the treatments of 4 authentic phenolic acids.

• Korean Journal of Weed Science
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• v.3 no.1
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• pp.39-49
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• 1983

By use of three paddy rice lines as the near-isogenic in plant type (Broom, Open, and Spread type in tillering angle), the interspecific competition patterns of rice plants with three important weed species (Cyperus serotinus, Eleocharis kuroguwai, and Potamogeton distinctus) under the three densities of weed standing (0.25 and 50 percent of the rice plants), were observed. Under the experimented conditions, paddy yields were varied more significantly with weed competition descriptions than with plant types of paddy rice. And spread typed rice was more competitive to the detected weed species, however, the broom and spread typed rice were to Potamogeton SP, among others. The result of the clustering analysis of crop-weed competition patterns, estimated by 1-Q mode correlation coefficients, indicated that the first-order component affecting the competition patterns of crop-weed was rather the plant types of rice than either weed species or weed standing densities.

• The Korean Journal of Ecology
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• v.25 no.5
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• pp.305-313
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• 2002

The physico-chemical characteristics of water and sediment, and structures of vegetation of the vascular hydrophytes were investigated in the West Nakdong River. Water quality was eutrophic according to the mean values and the ranges of water properties such as pH, DO, BOD, chlorophyll a, total nitrogen and phosphate, and other nutrients. A few cases were hypereutrophic for chlorophyll a level in summer. Soil reaction was weak acid. Composition of sediment was mainly sand except in SI(Sinan chideung) of which was mainly clay, and SU(Suan chideung) of which was mainly silt. Flora of vascular hydrophyte had 26 species and 1 variety comprising 16 families. Trapa japonica was dominant species in the sites of DU(Dunchido), GA(Garak chideung) and SU. Nymphoides peltata and Hydrocharis dubia dominated in DA and SI, respectively. Species diversity and evenness were relatively high in SI and SU but dominance was high in DA. After June, water lettuce(Pistia stratiotes) and water hyacinth(Eichhornia crassipes) were flowed from tributary to the river. Standing crop of macrohydrophytes was high in DA from April to August, but it showed maximum standing crop (445g·dw/㎡) in DU after disturbance by explosive growth of exotic plants in October. In comparison with those in 1985, total productivities in DU and GA decreased to 33.5%, and the reduction ratio of dominant species, Trapa japonica was 56.7%. Najas marina, N. minor, Myriophyllum spicatum and Nymphoides indica have disappeared ever since the Nakdong barrage was constructed in the Nakdong river. They were divided into three groups (GA-SU-DU, DA, SI) by cluster analysis. Introduction of the exotic species in this river caused decreasing of endemic plants including endangered species Euryale ferox and rare species Hydocharis dubia, and food plants for waterfowl such as Trapa japonica, Vallisneria asiatica and Potamogeton crispus.

• Korean Journal of Weed Science
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• v.3 no.1
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• pp.50-56
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• 1983

A study was conducted to evaluate the weed population as affected by repeated application of fertilizers for 15 years (nonfertilized, PK, NK, NPK, NPK+Compost, NPK+Straw and NPK+lime). Alopecurus aequalis authority did not grow at all without P application and lime reduced the population of A. aequalis. Total number of weeds were the largest at 5-10cm soil layer and increased by application of compost and straw. Monochoria vaginalis dominated in NPK+compost and NP plot. Scirpus hotarui dominated in NPK+straw. Both Eleocharis kuroguwai and Potamogeton distinctus dominated in nonfertilized plot. Numbers of M. vaginalis and S. hotarui were larger low pH 6 while that of E. kuroguwai and P. distinctus at pH 6 to pH 7. Incidence of M. vaginalis and S. hotorui was great at pH's lower than 6, while E. kuroguwai and P. distinctus favored pH's ranging from 6 to 7.

• The Korean Journal of Pesticide Science
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• v.6 no.1
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• pp.36-41
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• 2002

Characteristics of regrowth and starch degradation in perennial weed rhizomes were investigated in a greenhouse. Cyperus serotinus started regrowth at 24 days after treatment of 1.25 g ai/ha of pyrazosulfuron-ethyl. The regrowth of Sagittaria trifolia, Eleocharis kuroguwai, and S. pygmaea required $30{\sim}39$ days, and Potamogeton distinctus regrew at 55 days after treatment of 1.25 g ai/ha of pyrazosulfuron-ethyl. However, all of 5 perennial weeds hardly regrew until 45 days after treatment more than 5 g ai/ha of pyrazosulfuron-ethyl. Regrowth of C. serotinus 4-node rhizomes was 2 times higher than 2-node rhizomes, and $1{\sim}1.5g$ of E. kuroguwai large tubers regrew faster than $0.3{\sim}0.5g$ of small tubers treated with bensulfuron-methyl. Regrowth of C. serotinus was enhanced with delayed application of bensulfuron-methyl, however, 2-leaf stage of E. kuroguwai plants regrew better than 3 leaf stage of plants when treated with equal volume of bensulfuron-methyl. The critical periods of S. trifolia and E. kuroguwai growth depending upon the rhizome detachment were 12 and 18 days after sprouting, respectively. The starch stacked in the S. trifolia and E. kuroguwai tubers were exhausted at 18 and 27 days after sprouting, respectively. The highest level of sugar contents was showed at 9 days after sprouting in S. trifolia, and 18 days after sprouting in E. kuroguwai.

• 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.

• Journal of Wetlands Research
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• v.19 no.2
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• pp.193-201
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• 2017

This study was carried out to obtain basic ecological information required for wetland restoration in Korea where wetland is very deficient. To arrive at the objective, we collected the basic ecological information for wetland restoration in four Doombeongs located on Goesan of Chungcheongbuk-do (province), central Korea where maintains relatively integrate feature of Doombeong. Synthesized horizontal distribution of vegetation based on vegetation established naturally except that established by artificial interference, Potamogeton distinctus community, Spirodela polyrhiza community, Sagittaria aginashi community, Trapa japonica community, Scirpus triangulatus community, and Sparganium japonicum community, Persicaria thunbergii community, Juncus effusus var. decipiens community, Ludwigia prostrata community, Humulus japonicus community, Persicaria nodosa community, Miscanthus sacchariflorus community, Phragmites communis - P. japonica community, and Scirpus radicans community, S. gracilistyla community, Spiraea prunifolia for. simpliciflora community, and Rosa multiflora community, and Salix koreensis community and Acer tataricum subsp. ginnala community tended to be established in aquatic zone, herbaceous plant dominated vegetation zone, shrub dominated vegetation zone, and tree and sub-tree dominated vegetation zone, respectively. As the result of DCA ordination based on vegetation data collected from several Doombeongs and their surrounding areas, plant communities tended to be classified into aquatic, wetland, and riparian plant dominated stands. Spatial niche and species composition of major plant communities composing those stands were suggested as the reference information for creating ecological pond as a type of wetland. Further, the importance of wetland and the necessity of wetland restoration was discussed based on functions that the wetland displays.