• Korean Journal of Weed Science
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• v.17 no.2
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• pp.147-156
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• 1997

The survey of weed population in apple orchard was conducted to investigate basic information on weed flora and its ecology at 27 locations in 1996. The weed species observed include 7 species of grasses, 60 species of broadleaves and 2 species of sedges, and the ratio of annual weed vs perennial weed was 64 : 36. Major dominant weed species by frequence were Chenopodium album, Capsella bursa-pastoris, Digitaria sanguinalis, Rorippa islandica, Alopecurus aequalis and Erigeron canadensis. While, on the basis of dry weight, the most dominant weeds were C. album followed by E. canadensis, A. aequalis, R islandica and R indica. The dominant weed species in middle-north Kyeongbuk region were C. bursa-pastoris, C. album, R indica and R islandica, were E. canadensis, Persicaria hydropiper, A. aequalis and Arenaria serpylliforia in Chungbuk region and were A. aequalis, E. canadenris and R islandica in Honam region.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.11-18
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• 1984

The effect of transplanting method of rice seedlings on weed occurrence was investigated at the Yeongnam Crop Experiment Station in 1983. Rice was transplanted by hand and machine and eleven common herbicides were applied. The greatest weeds were harvested from the plot that rice was not transplanted and more weeds encountered at machine transplanted plot than hand transplanted plot. The degree of weed suppression by rice plant itself was 50% for machine transplatning and 55% for hand transplanting, respectively. Simpson index and community dominance of weed species were the highest in hand transplanting and followed by machine transplanting and no rice plot in order. Rice grain yield was exponentially correlated with the amounts of weed occurrence and more yield loss exhibited at machine transplanting than hand transplanting in the same amount of weeds. In the herbicidal activity, most of herbicides performed better at hand transplanting than machine transplanting while the degree of difference between transplanting methods varied depend on herbicide used.

• Korean Journal of Weed Science
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• v.12 no.3
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• pp.223-229
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• 1992

Very recently, the cultural pattern of paddy rice in Korea was transitted in a short period, and resulted as earlier in season and more in fertillizer application among others. Specially the weed emergence in paddy fields was drastically increased as affected by change of cultural pattern into early planting and into direct seeding methods. Of course, the direct-seeding in row seeding induced more weeds than in broad-cast direct -seeding. By maintaining the water level with saturation of the paddy surface induced more weeds, relatively more annual weeds than by deep in water level, respectively. Relatively more annuals in number of species and in emerged quantity comparing with perennials was caused by the shifting of cultural methods from transplanting to direct seeding. The severe weed competition damages were mainly resulted due to the shading by taller plant heights of weeds than crop during the whole growing seasons. Conclusively, accepting of direct seeding methods in paddy rice culture in Korea, the present bases for weed control methods ought to be naturally and effectively improved to meet the newly made weed problems.

• Weed & Turfgrass Science
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• v.2 no.2
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• pp.131-137
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• 2013

The study was carried out to obtain the basic information on distribution and occurrence of weeds including resistant weeds to sulfonylurea herbicides in paddy fields of Gyeongbuk province. In weed distribution on life cycle, annual weed was occupied by 91.8% and perennials were 8.2%, respectively. In morphological distribution of weeds, broad leaf weeds were 85.7%, sedges was 9.1%, and grass weed was 3.8%, respectively. Sulfonylurea-resistant weeds in paddy fields of twelve regions were widely occurred except for Yecheon region. The six sulfonylurea resistant biotypes occurred in paddy fields of Gyeongbuk province were Lindernia dubia, Eleocharis kuroguwai, Monochoria vaginalis and Ludwigia prostrata. It revealed that occurrence rate and area of sulfonylurea-resistant weeds were about 15.9 % and 22,420 ha in Gyeongbuk province.

• Life and Agrochemicals
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• s.246
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• pp.54-55
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• 2009

유럽이 원산지인 외래잡초로 다년생이다. 목초지에 발생시 초지의 품질을 떨어뜨리고 애기수영, 쑥 등의 다른 잡초의 발생을 촉진하여 초지를 황폐화시킬 수 있다. 경엽처리 제초제를 살포할 경우 사용에 주의하여야 한다.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.176-187
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• 2015

The weed flora in the Codonopsis lanceolata upland fields were surveyed in Hoengseong and Jeju in May, August, and October of 2014. The objectives of this study were to use the survey data for establishing weed control methods and to bring awareness of possible problematic weeds occurred in C. lanceolata upland fields in Korea. Altogether 207 weed species of 47 families were identified, of which 87 were annual, 47 species were biennial and 73 were perennial. Based on the morphological characteristic of the leaves, 182 species were broad leaves, 18 species were grasses, and 7 species were sedges. The dominance was highest in the Artemisia princeps followed by Digitaria ciliaris, Commelina communis, Persicaria longiseta and Echinochloa crus-galli etc. Fifty-nine species were exotic weeds with 29% of a total presence, of which Erigeron annuus was highest, followed by Crassocephalum crepidioides, Bidens frondosa, Hypochaeris radicata etc. In the PCA plot, weeds presented in the C. lanceolata upland fields of Hoengseong were divided into three groups, E. annuus, Sigesbeckia pubescence and C. communis communities and those of Jeju were divided into four groups, C. crepidioides-Cyperus iria, Spergula arvensis, Poa annua and Youngia japonica communities.

• Korean Journal of Weed Science
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• v.8 no.2
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• pp.164-168
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• 1988

In order to get basic information for establishing weed control methods in apple orchards, weed distribution was surveyed at 2 locations in Chungnam Province at 15 days intervals. In apple orchard 48 weed species (18 families) were distributed and Chenopodium album and Polygonum hydropiper were dominated and Digitana sanguinalis, Portulaca oleracea, and Erigeron canadensis were also abundant among them. Highest number of weeds emerged in April and dry weight of weeds were heavy in June and October, especially in summer broadleaf weeds and winter broadleaf weeds, and winter grasses were abundant in spring. Seasonal Shannon's diversity index(H'), maximum diversity(H max'), eveness (J') for the Shannon diversity index, and Simpson index were high in apple orchards. Interspecific competition was more severe than intraspecific competition.

• 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.

• Korean Journal of Weed Science
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• v.18 no.4
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• pp.356-363
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• 1998

In general weed vegetation analysis has been applied to the study of weed population shift. However, it is a limited tool for understanding a problem region and a specific weed species in a certain area. Recently GIS may be used as an important tool to solve this target or to conduct specific field analysis which enables to introduce a reasonable management strategy. Thus, the GIS study was carried out to understand an integrated weed population changes between 1981 and 1992 in Korea. The nationwide weed survey was performed through the whole rice paddy fields in 1981 and 1992. Weed occurrence was totally different over whole country based on these data. In 1981 a region with high weed occurrence was at western and central areas of Korea in terms of weed population density but this was changed into western and southern area in 1992. In both years there were high weed population density at Taean, Seosan county of Chungnam province in Korea. Thus, this particular area may be needed to introduce a special strategy to reduce weed population density and/or to control problem weed species.

• Weed & Turfgrass Science
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• v.5 no.1
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• pp.5-9
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• 2016

This survey was conducted to identify weed occurrence and to investigate weed management methods in the apple orchard fields in Chungnam province including Daejeon and Sejong from April to June and from September to October, 2015. In this survey, 64 weed species in 27 families including 39 annuals and 25 perennials were identified. Based on the importance values, the most dominant weed species in the first survey was Poa annua (6.51), followed by Veronica didyma (5.36), Plantago asiatica (5.36). In the second survey, Stellaria media (5.73), Digitaria ciliaris (5.36), and Rumex crispus (5.18) were dominant. When the 64 weed species were classified by family, the most abundant weed species belong to Compositae (12 species), followed by Poaceae (7 species), Polygonaceae (6 species), and Cruciferae (6 species). These 31 weed species in the most occurred four families accounted for 48% of total weed occurrence. Based on the questionnaire survey in which weed management methods in the apple orchard were asked, applied mowing + herbicide, mowing + tillage, and mowing + sod-culture was methods commonly conducted in apple orchard fields.