• Korean Journal of Weed Science
• /
• v.8 no.3
• /
• pp.291-294
• /
• 1988

About 136 weed species belonging to 44 families occurring in summer observed in Cheju island. The Compositae was the most widely occurring family covering 29 weed species, followed by 16 species in Graminae, 14 in Leguminosae, 13 in Rosaceae, 10 in Polygonaceae etc., The dominant weed species detected in range areas of Cheju island were Trifolium repens, Botrychium virginianum, Rosa multiflora, Miscanthus sinensis, Imperata cylindrica. The range areas of Cheju island consisted of the communities of Artemisia princeps-Botrychium virginianum, Artemisia princeps-Erigeron borariensis and Dianthus sinensis, and Artemisia-Lespedeza bicolor and Miscanthus sinensis and then the differential species of their communities were Botrychium virginianum, Erigeron boriensis, and Lespedeza bicolor and Miscanthus sinensis, respectively. The species of the high frequencies occurring in investigated sites were Artemisia princeps, Cirsium rhinoceros, Hydrocotyle ramijlora, Rosa multiflora, Sanguisorba officinalis, Rubus crataegifolius, Potentilla fragariodes, Erigeron annus, Plantago asiatica, Oxalis corniculata, Mosla dianthera in order.

• Korean Journal of Weed Science
• /
• v.18 no.1
• /
• pp.1-11
• /
• 1998

This experiment was conducted to investigate weed infestation and to determine effective weed control methods in direct-seeded rice. Twenty two weed species occurred in dry- and water-seeded rice, which was mainly composed of annual weeds. Dominant weed species in dry-seeded rice were Cyperus difformis, Echinochloa crus-galli, Aneilema keisak and Digitaria sanguinalis in discending order. Dominant weed species in water-seeded lice were E. crus-galli, C. difformis, Monochoria vaginalis and Scirpus juncoides. E. crus-galli emerged at 7 days after sowing. In water-seeded rice, E. crus-galli emerged at 5 days after sowing, and M vaginalis, S. juncoides and C. difformis at 8~10 days after sowing. Mean days to emerge important weeds was 20 days in dry-seeded rice and 13 days in water-seeded rice. Leaf development of weeds was faster than that of rice in dry-seeded rice. In water-seeded rice, E eras-galli was more vigorous than rice, but leaf development of other weeds were slower than that of rice. Changes in number of weeds and dry weight oil weed species varied depending upon weed species in the direct-seeded rice. Dry weight of weeds were increased greatly from 30 days to 60 days after sowing in dry-seeded rice. Number of weeds tended to increase up to 40 days after sowing drastically, and then trend of the increase was dull thereafter. Dry weight and number of weeds increased up to 20~60 days after sowing in water-seeded rice. Most effective herbicide treatments was foliar application of cyhalofop/bentazon at 20 days after sowing followed by fenoxaprop/bentazon at 45 days after sowing in dry-seeded rice. All herbicide treatments except foliar applications were very effective to control weeds in water-seeded rice. Slight phytotoxicity was observed in foliar applied fenoxaprop/bentazon at 45 days after sowing in water-seeded rice, but it did not affect rice yield.

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

• Spatial Information Research
• /
• v.3 no.1
• /
• pp.47-53
• /
• 1995

The weed survey in lowland rice fields through Korea was conducted in 1992 to determine a change of the weed communities based on different regions, soil types, planting methods, and cultural practices. GIS was applied to identify a spatial analysis of predominant weed species in specific region. On behalf of vegetatine analysis such as absolute and relative density, absolute and relative frequency, importance value, and summed dominance ratio(SDR), there was highly dominant with a perennial weed species, Eleocharis kuroguwai Ohwi over whole country. However, in particular it was most predominant at southem area of Gyunggi province in Korea. Thus, rice farmers of this area have to introduce a specific comperhensive control strategy against this predominant weed species.

• Korean Journal of Weed Science
• /
• v.5 no.1
• /
• pp.14-18
• /
• 1985

This experiment was conducted to characterize the weed flora in protected semi-irrigated rice seedbeds. There are 22 species in 16 genera and 12 families, consisting of 13 annual and 9 perennial weeds in protected semi-irrigated rice seedbed in Jeonbug province. The highest frequency was obtained with Echinochloa crusgalli(L.) Beauv., Cyperus difformis L., Eleocharis acicularis Rome et Schult, and Monochoria vaginalis Presl. Sites showing Simpson's index ranging from 0.1 to 0.5 reached 82% and 89% of all sites studied in 1983 and 1984, respectively. Dominant weed species were E. crus-galli and C. difformis in both years studied and the community dominance has changed from 0.67 in 1983 to 0.61 in 1984.

• Weed & Turfgrass Science
• /
• v.2 no.4
• /
• pp.341-347
• /
• 2013

The survey of weed occurrence was conducted to identify problematic weed species on the paddy field. Total 524 sites of the 17 regions in Chungnam Province in Korea were investigated from June to August, 2013. In the whole region, 23 weed species were identified including 19 annuals and 4 perennials. The most dominant weed species in Chungnam paddy fields were Echinochloa crus-galli (25.3%), followed by Monochoria vaginalis (11.9%), Eleocharis kuroguwai (10.3%), Bidens tripartite (9.3%) and Aneilema japonicum (8.5%). The 95.2% of the investigation sites was determined under dominance value 1 (range of cover <10: numerous individuals) by Braun-Branquet indicating proper weed control in the paddy fields. This information could be useful for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods in Chungnam Province in Korea.

• Weed & Turfgrass Science
• /
• v.6 no.1
• /
• pp.11-20
• /
• 2017

Ninety species belonging to 28 families of weeds were identified in Korean rice fields. They were divided by eight provinces and 19 agro-climatic zones to be used as basic data of weed control. Looking at the regional weed occurrence, there were 52 species of 20 families in Gyeonggi, 37 species of 17 families in Gangwon, 41 species of 15 families in Chungbuk, 21 species of 12 families in Chungnam, 24 species of 13 families in Jeonbuk, 54 species of 21 families in Chonnam, 36 species of 20 families in Gyeongbuk, and 32 species of 16 families in Gyeongnam province, respectively. The most dominant family was Poaceae followed by Cyperaceae and Asteraceae. Mostly dominant species were Echinochloa spp., Monochoria vaginalis var. plantaginea, Scirpus juncoides var. hotarui, Eleocharis kuroguwai, and Sagittaria sagittifolia subsp. leucopetala with slight differences among the provinces. Although there were some differences in 18 climate zones from Taebaek sub-highlands to the southern part of the East Coast (except for the Taebaek Highland), the dominant species were Echinochloa spp., Monochoria vaginalis var. plantaginea and Scirpus juncoides var. hotarui. The most dominant family was Cyperaceae followed by Poaceae and Asteraceae. The differences of weed occurrence between provinces and agro-climatic zones were largely influenced by various weather conditions rather than the provinces. The changes in cultivation mode and herbicide use might influence as well.

• Weed & Turfgrass Science
• /
• v.4 no.2
• /
• pp.77-84
• /
• 2015

We surveyed the distribution pattern of weeds in onion, garlic, potato, and barley fields including 304 sites of Gyeongsangbuk-do. The weeds were summarized as 30 family and 125 species in onion crop field, 29 family and 101 species in garlic field, 30 family 88 species in potato field, finally 27 family and 108 species. Compositae was dominant family (26.4%, 33 species), followed by Polygonaceae (8.8%, 11 species), Cruciferae (8.8%, 11 species) in onion field. Compositae was also dominant family (24.8%, 25 species) in garlic field, it was 22.7% (20 species) in potato field, and it was also 24.1% (26 species) in barley field, respectively. Among these winter crops, major five families were occupied 61.1, 58.4, 58.0 and 57.5% in turn at barley, onion, potato and garlic fields. The PCA-covariance plot analysis for investigation of occurrence pattern of weeds by four winter crop fields revealed that the occurrence pattern of weed species in barley field was distinguished by Alopecurus aequalis var. amurensis, Stellaria alsine var. undulate and Stellaria aquatica.

• Korean Journal of Weed Science
• /
• v.7 no.2
• /
• pp.156-164
• /
• 1987

Allelopathic activity of dominant upland weed species was determined using aqueous and methanol extracts and dried residues of the weeds. Germination and seedling growth of radish (Raphanus sativus L.) and sesame (Sesamum indicum L.) were greatly inhibited by 2% (w/v) aqueous extracts of Artemisia asiatica Nakai and Portulaca oleracea L., respectively. Great phytotoxicity on both indicator plants occurred by 2% (w/v) aqueous extracts of Capsel/a bursa-pastoris (L.) Medik. A complete inhibition in germination and seedling growth of radish was caused by 2% (w/v) methanol extract of A. asiatica. There was about 90% inhibition in germination and seedling growth of sesame due to 2% (w/v) methanol extracts of A. asiatica, P. oleracea and Trifolium repens L. Phytotoxic effects varied with extract solution, weed species and indicator plants employed, indicating that the weed species contained different contents and kinds of allelopathic chemicals. Water potential and pH adjusted to those of the extracts did not affect germination and seedling growth of the indicator plants. Phytotoxicity increased with increasing concentration of the extracts obtained from four suspected alleopathic weeds. Soil-incorporated plant residues of A. asiatica and P. oleracea caused greater phytotoxicity on radish than those of C. bursa-pastoris and T. repens.

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