• Korean Journal of Agricultural Science
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• v.42 no.4
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• pp.335-339
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• 2015

This paper reviews current status of weed science in Japanese regional agricultural systems based on the 54th Annual Meeting of the Weed Science Society of Japan. About 300 researchers from 5 countries including Korea participated in the Conference and presented 100 papers in research areas. This congress has an purpose to discuss new troubles, findings and results of weed science. Weed science faces big challenges such as increase in herbicide-resistant weeds, gene-flow from transgenic crops, and invasive weeds. Major research topics were invasive weeds and their ecology, allelopathy, weed management in paddy field, weed management in field crops, and herbicide resistance. Weed control and herbicide resistance management in paddy field were a main object of research. To prevent the increase of problematic weeds and to overcome food crisis, the importance of weed-related researches has been raised. Therefore it is expected that various weed management systems and control of herbicide resistant weeds should be studied continuously in the weed science.

• Weed & Turfgrass Science
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• v.3 no.1
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• pp.1-5
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• 2014

This paper reviews current status of weed science in Asian-Pacific regional agricultural systems based on the 24th Asian-Pacific Weed Science Society Conference. About 190 researchers from 16 countries including Korea participated in the Conference and presented 160 papers in 11 research areas. Major research topics were invasive weeds and their ecology, allelopathy, weed management in paddy field, weed management in field crops, and herbicide resistance. Because rice is a major food crop in Asian countries, weed control and herbicide resistance management in paddy field were a main object of research. Weed control in maize, soybean and wheat has also been studied continuously. To prevent the increase of problematic weeds and to overcome food crisis, the importance of weed-related researches has been raised. Therefore it is expected that various weed management systems and control of herbicide resistant weeds should be studied continuously in the future.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2008.04a
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• pp.128-130
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• 2008

• 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.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.276-283
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• 2014

This study was conducted in order to investigate the distribution pattern of weeds on upland crop field in northern Gyeonggi-do. The weeds were summarized as 201 taxa including 42 families, 129 genera, 178 species, 1 subspecies, 21 varieties and 1 form. One hundred and thirty one species were classified to annual plants, accounting for 65.1% and 70 species were classified to perennials, accounting for the rest of 34.9%. Compositae was dominant family (21%), followed by Gramineae (12%), Polygonaceae (7%) and Brassicaceae (5%). Among the weeds appearing in the fields of northern Gyeonggi-do, the invasive weeds were classified to 62 species in18 families. The most dominant weed species in the fields were Portulaca oleracea, followed by Echinochloa crus-galli, Amaranthus lividus. Detrended correspondence analysis for investigation of occurrence pattern of weeds by crops revealed the occurrence pattern of weed species in adlay field were different from those in other crop fields. This information could be useful for establishment of weed control methods in northern Gyeonggi-do.

• Journal of Ecology and Environment
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• v.35 no.4
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• pp.313-322
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• 2012

A 2-year study (2010-2011) was carried out in order to evaluate the effects of bean and maize intercropping. The experiment tested five different cropping systems: sole cropping of each crop, as well as intercropping of maize/bean with the ratios of 1:3 ($M_1B_3$), 2:2 ($M_2B_2$) and 3:1 ($M_3B_1$), each of which took place in the presence of two weed management systems (no weed control and weed eradication through manual removal), in a factorial experiment based on randomized complete block design using three replicates. Tests of homogeneity of variance for combined data over two years showed that data of both years could be analyzed together. The results showed that the effect of intercropping treatments on all measured traits in maize and bean were significantly different. A minimum land equivalent ratio (LER) for maize (0.78) was obtained for $M_3B_1$ under conditions of no weed control, while the highest LER (1.03) was observed in $M_3B_1$ under weed-free conditions. The highest (0.99) and lowest (0.70) LER values for beans were recorded for $M_1B_3$ under weed-free conditions and $M_3B_1$ under conditions of no weed control, respectively. $M_1B_3$ under weed-free conditions showed the highest total LER (2.02), while $M_3B_1$ under conditions of no weed control showed the lowest (1.48). Results of this study indicated that intercropping bean and maize can be an effective method to increase total productivity, and that the $M_1B_3$ system was the best cropping system for high productivity.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.159-175
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• 2015

Surveys of weed species on upland fields were conducted in Korea to investigate the occurrence of weed flora from April to May 2014 for winter crop fields and from July to August 2014 for summer crop fields. From the nation-wide survey, 375 weed species in 50 families were identified and classified to 162 annuals, 78 biennials and 135 perennials. Based on the occurrence ratio, the most weed species belonged to Compositae (73 species). 44 and 25 weed species belonged to Poaceae and Polygonaceae, respectively, and these 183 weed species in the most five families accounted for 49% of total weed occurrence. While 287 weed species in 45 families occurred in the winter crop fields, 339 weed species in 47 families occurred in summer crop fields. The most dominant weed species in Korean upland fields were Digitaria ciliaris, followed by Portulaca oleracea, Acalypha australis, Chenopodium album, Rorippa palustris etc. 129 weed species in 25 families were considered as exotic weeds. Based on the importance analysis, the highest value was C. album followed by Amaranthus lividus, Conyza canadensis etc. This information could be useful for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods in upland fields of Korea.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.139-146
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• 1997

The experiment was conducted at Gyeongbuk Provincial Rural Development Administration in 1996 to obtain basic information on weed ecology and effective weed control in direct-seeded rice fields under different seeding types and seeding times. A large number of upland weeds such as Echinochloa crus-galli, Digitaria sanguinalis, Capsella bursa-pastoris and Stetaria viridis etc occurred at early growth stage, while Eleocharis kuroguwai, Aneilema keisak and Cyperus serotinus dominated at late stage in dry seeded rice field. In wet seeded rice field, the dominance of E. crus-galli was lower and the occurrence of M. vaginalis and A. keisak were higher than in dry seeded field. Amount of weed occurrence in dry seeded field was 1.8 to 2.4 times greater than in wet seeded field and it increased with delaying seeding time. Increasing rate of weed occurrence through whole life cycle was the highest at 20 days after seeding (DAS) to 40 DAS, regardless of seeding types and seeding times. Simpson index in wet seeded field was higher than in dry seeded field and it gradually increased as growing of dominant species. For F-value test, it was recognized as statistical significant in seeding types, seeding times and interaction of two factors.

• Weed & Turfgrass Science
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• v.4 no.4
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• pp.338-347
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• 2015

Reinforcement cells are used to aid grass growth and taken together, this serves to extend greenery beyond the conventional spaces of lawns, tree pits, gardens, and parks, and is advantageous to urban cities since space for greening is often limited. Drought has variable effects on plant life and the resilience of turf to drought resistance also varies with species. Changes in photosynthetic ability were more pronounced for media rather than grass species. The media of sand without organic matter was found to be least suited for drought resistance. Normalized difference vegetation index (NDVI) and digital image analysis (DIA) data were generally in favour of Zoysia species as oppose to A. compressus. In A. compressus, selective traits such as, a more extensive root system and lower specific leaf area (SLA) were not an underlying factor that assisted this grass with enhanced drought resistance. Generally, WUE was found to be strongly related to plant characterises such as overall biomass, photosynthetic features as well as the lushness indexes, and specific leaf area. This study found a strong relationship between WUE and a suite of plant characteristics. These traits should serve as useful selection criteria for species with the ability to resist water stress.

• Weed & Turfgrass Science
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• v.3 no.2
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• pp.71-77
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• 2014

Surveys of weed species in paddy fields were conducted in Korea to identify weed occurrence from June to September 2013. Total 3,434 sites of paddy fields in 155 City/Gun, eight Provinces were investigated. From the nation-wide survey, 90 weed species in 28 families were identified and classified to 52 annuals, 3 biennials and 35 perennials. Based on the occurrence ratio, the most weed species belonged to Poaceae (18 species). 17, 8 and 6 weed species belonged to Cyperaceae, Scrophulariaceae and Polygonaceae, respectively, and these 49 weed species in the most four families accounted for 54% of total weed occurrence. The most dominant weed species in Korean paddy fields were Echinochloa spp. (17.4%), followed by Monochoria vaginalis (12.4%), Eleocharis kuroguwai (7.8%), Bidens tripartite (9.27%), Scirpus juncoides (6.2%) and Sagittaria sagittifolia (6.1%). This information could be useful for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods in paddy fields of Korea.