• 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.

• Weed & Turfgrass Science
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• v.3 no.1
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• pp.50-55
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• 2014

This study is aimed at classifying the syntaxa of Ceratopteris thalictroides dominant community on the Nakdong River, and to collect basic data for research of habitat. The communities were carried out by using the Z.-M. School's method and numerical classification technique. The result of syntaxa was classified three communities such as Persicaria japonica-Ceratopteris thalictroides community, Lindernia procumbens-Ceratropteris thalictroides community, and Limnophila indica-Ceratopteris thalictroides community. The ordination analysis displayed the vegetation types with respect to complex environmental gradients. After ordination and clustering analysis, the effective humidity, soil stability, trampling effects, anthropogenic effects and flooding frequency were identified as the important factors deciding the vegetation pattern. It was pointed out to establish a long-term ecological site for protecting such vulnerable vegetation against overexploitation and global climate change.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.157-162
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• 1997

This study was conducted to investigate the change of weed community on paddy-upland rotation in 1996. In paddy-upland rotation, dominant weed species in paddy condition were Cyperous amuricus, Echinochloa crus-galli, Rotara indica and Lindernia procumbens. They were E. crusgalli, Digitaria sanguinalis and C. amuricus in upland condition. The number of weed occurrence on paddy and upland rotation reduced about 74-78% as compared with continuous paddy and upland condition. Similarity coefficient and Simpson index on paddy and upland rotation was 8-64, 0.34-0.35, respectively.

• Weed & Turfgrass Science
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• v.5 no.3
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• pp.126-135
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• 2016

The surveys of weed species in pastures were conducted in Jeju Island, Pyeongchang Gangwon, and Seosan Chungnam throughout 2013, 2014, and 2015 in order to understand the current status of the weed flora in Korean pastures and to utilize the survey data for basic measure of them. From the surveys, 275 species of 52 families including 83 exotic species were identified and classified into 77 species of annuals, 55 species of biennials and 143 species of perennials. Looking regionally, 207 species of 49 families, 62 species of 14 families, and 136 species of 36 families were occurred in Jeju, Pyeongchang and Seosan, respectively. Based on the importance values, the most dominant species was Rumex obtusifolius followed by Artemisia princeps, Trifolium repens, Digitaria ciliaris, Rumex acetosella etc. in order. The dominance of exotic species was the highest in Rumex obtusifolius followed by Trifolium repens, Rumex acetosella, Erigeron annuus etc. According to the surveys of past and present a pasture weed community has been changed, i.e., Erigeron annuus, Artemisia princeps, and Potentilla fragarioides var. major were dominant in 1990 and Artemisia princeps, Trifolium repens and Rumex acetosella were dominant in 2004. On the other hand, the dominant species at the pastures were changed into Rumex obtusifolius, Artemisia princeps, and Trifolium repens in 2015.

• Korean Journal of Weed Science
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• v.10 no.3
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• pp.192-196
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• 1990

Eleven herbicides were treated in soybean fields of Dukso and Yeoncheon in Gyeonggi province. These herbicides were classified by two-dimensional ordination analysis based on important values of the weed flora which were obtained after application of herbicides. Weed community types were E. crus-galli(56%)-D. adscendens (14%) -C. album (10%)-P. oleracea (8%) and P. oleracea (58%)-E. crus-galli (29%) -A. mangostanus (5%) -D. adscendens (3%), respectively. From soybean field at Dukso, 11 weed community types or 11 herbicide groups were obtained. And at Yeoncheon, 9 weed community types or 9 herbicide groups were classified. At treated blocks with clomazone and bentazon, C. amuricus and E. crus-galli dominated respectively. And at treated blocks with quizalofop, haloxifop and alloxydium, P. oleracea dominated remarkably. The herbicides classification by the two-dimensional ordination analysis could be used more effectively to selecting herbicides for reciprocal and systematic weed control than by similarity analysis.

• Korean Journal of Weed Science
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• v.10 no.2
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• pp.67-74
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• 1990

Weed species investigated along the Nakdong River on September, 1989 were 105 species in 29 families. Vegetation analysis along the Nakdong River using a two dimensional ordination diagram showed the existence of six plant community types, namely, Humulus japonicum, Persicaria thunbergii, Artemisia capillaris, Persicaria blumei-Setaria viridis-Digitaria sanguinalis and Phragmites communis. Especially the largest community type, Phragmites communis had dominant weed species such as Humulus japonocum, Arundinella hirta, Persicaria thunbergii, Setaria viridis, Sasola collina and Persicaria perfoliata.

• Journal of Ecology and Environment
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• v.33 no.4
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• pp.317-323
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• 2010

Nutrient availability is a critical component of agroecosystems, and is relevant to both above- and below- ground interactions. The principal objective of this study was to determine how the cessation of fertilization affects the communities of weeds and soil organisms in a corn/wheat field. Changes in dominant weed species, substrate-induced respiration, and the population density of nematodes and microarthropods were evaluated. Microbial substrate-induced respiration (SIR) and the population density of microarthropods decreased following the cessation of fertilization and were partly correlated with the aboveground weed biomass. The cessation of organic fertilizer application but continuing application of inorganic fertilizer reduced the population density of nematodes. In response to the cessation of fertilization, weed communities were dominated by species with little dependency on fertilization. Amaranthus retroflexus was identified as the most dominant species in the corn field; however, it was replaced by Digitaria ciliaris after the cessation of fertilization. In the wheat field, the cessation of fertilization led to a rapid reduction in the biomass of most weeds, except for Vicia angustifolia, supposedly as the result of symbiotic nitrogen fixation. Additionally, the fact that weed biomass was partially correlated with SIR or the population density of microarthropods may reflect a mutual feedback between soil organisms and weeds. The results indicate that the cessation of fertilization alters communities of weeds and soil organisms through changes in weed biomass and interactions with symbiotic microorganisms.

• Korean Journal of Environment and Ecology
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• v.18 no.2
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• pp.191-196
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• 2004

Mt. Deogyusan, 1,614m in altitude, is located in the southwest of South Korea. Around Mt. Duckyu, many Korean endemic and rare plants are populated, so it is considered a very important biogeographical area where the temperature zones of northern and southern plants are crossed. Because it is the graceful figure of Mt. Duckyu, it is a common mountain where many tourists visit frequently. Continuous tourist's visit may cause a bad influence on vegetation around the climbing paths. Therefore, weed community around the climbing paths on Mt. Duckyu, where visitors exert a bad influence directly on its community by coming in and out, was surveyed phytosocialogically. Our surveys have been accomplished from July to August, 2003. Weed communities formed around the climbing paths on Mt. Duckyu were divided into several patterns and analysed. They have been divided into 8 communities and 4 subcommunities. Community A: Plantago asiatica community, A-a: Carex bostrychostigma subcommunity, A-b: Artemisia princeps var. orientalis subcommunity, B: Sasa borealis community, B-a: Carex siderosticta subcommunity, B-b: Veratrum parulum subcommunity, C: Rubus crataegifolius community, D: Hosta longipes community, E: Tripterygium regelii community, F: Miscanthus sinensis var. purpurascens community, G: Carex okamotoi community, H: Lespedeza maximowiczii community. The flora surveyed in these communities was constituted of 34 families, 83 genera, 12 varieties, and 92 species. Wild plants such as Plantago asiatica, Artemisia princeps var. orientalis, Rubus crataegifolius, Sasa borealis and Miscanthus sinensis var. purpurascens were mostly light loving plants and higher resistant plants against the stamping pressure.

• Korean Journal of Weed Science
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• v.31 no.1
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• pp.34-40
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• 2011

Cover crop can be used to suppress weeds by competition for light and nutrient. Objective of this study was to evaluate the effectiveness of legume cover crops on change of weed community in no-till corn cultivation. Two legume cover crops, hairy vetch and crimson clover were grown in the field, and succeeding corn was sown on 4 May, 2010. The distribution of weed was surveyed at 15 April, 1 June, and 20 August. At 15 April, the weed biomass in hairy vetch field was higher than in crimson clover field. The dominant weeds were Capsella bursa-pastoris L. and Stellaria aquatica L. in hairy vetch and crimson clover fields, respectively. At vegetative stage of corn, occurred weeds in hairy vetch and crimson clover fields were four and six species, respectively, while the weed was occurred with nine species in conventional. Also the dry weight of weed was decreased by 82 and 75% in hairy vetch and crimson clover fields compared to conventional. On the other hand, after harvest of corn, occurred weed in hairy vetch, crimson clover and conventional was five, four and five species, respectively. Dry weight percentage of occurred weed in conventional was 23.5%, and the value was higher than 13.8 and 14.7% in hairy vetch and crimson clover fields, respectively. Stellaria aquatica L. as winter annual weed only occurred in cover crop field during corn growing season. It is these possibilities that low soil temperature and light interception by soil cover of legume cover crop.