• Korean Journal of Weed Science
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• v.15 no.3
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• pp.175-182
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• 1995

The experiment was conducted to obtain basic information on weed ecology and effective weed control in direct-seeded rice Gelds at National Yeongnam Agricultural Experiment Station in 1994. Double cropping system of rice-barley reduced weed occurrence about 30% as compared with rice single cropping due to allelopathic effect of barley residue or stubble. Occurrences of red rice (weedy rice), barnyard grass and water foxtail were closely related with tillage method; the greatest occurred in no tillage plot followed by rotavation only and plow plus rotavation. Period of seed germination of barnyard grass and carbgrass varied with temperature and soil depth. In the same environmental condition, the germination period of barnyard grass shortened 3 to 5 days as compared with that of carbgrass. Two systematic applications of herbicides, that is, the first application at 10 to 15 days after seeding and the second at just after flooding, were the most recommendable system in dry-seeded rice field in terms of weed suppression and yield capacity.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.4
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• pp.389-394
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• 2011

This experiment was carried out to find effective weed control method of henbit deadnettle ($Lamium$ $amplexicaule$ L.) on cultivating field of Italian ryegrass ($Lolium$ $multiflorum$ Lam) using herbicide in Grassland and Forages Division, National Institute of Animal Science, RDA, Cheonan from 2008 to 2009. When Onehof was treated two times of spray, weed control ratio was most high as 90%, but this method can not be used because of much damage to Italian ryegrass. When MCPP was treated two times of spray, weed control ratio was high as 82%, and damage to Italian ryegrass was very insignificant. Especially, when the spray of MCPP was treated two times, dry matter yield of Italian ryegrass was 11,427 kg/ha, but that of non treatment was 1,658 kg/ha. That is to say, forage harvest was impossible in non treatment field. According to these results, to control henbit deadnettle on cultivating field of Italian ryegrass using herbicide, you need to treat with two times of spray of MCPP in mid-March. If you do, you can get regular harvest as much as 11,427 kg/ha.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.96-106
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• 1984

Changes in weed floras and development of plant resistance to herbicides seemed to be closely related with increased and repeated use of herbicides. Herbicide use increased from 5% of the total consumption of pesticide in 1950 to 45% in 1976 in world basis. About 200 herbicides have been introduced to agriculture so as to control about 206 weed species which have been recorded important to human beings. In Korea, there was about 351 times in increased use of herbicides from 1966 to 1982. Interspecific selection by herbicide is mainly responsible for changes in weed floras and resulted in varying tolerance or susceptibility to herbicides, together with the changes of agricultural practices. The present trend toward continuous cereal cultivation throughout world will lead to type of changes in weed floras favorable to therophyte which can survive under unfavorable conditions as seeds rather than the types of geophyte which can survive unfavorable seasons as buds placed below soil surface. However, geophyte such as Sagitaria pygmaea, and Scirpus jurtcoides, and Cyperus rotundus and Cynodon dactylon in temperate warm climate become severe paddy weeds, presumably because of the removal of annual weeds by herbicides. Since differential tolerance to 2,4-D was firstly reported in Agrostis stolofera, about 30 species of weeds in 18 genera are presently known to have developed resistance to triazine herbicides. Resistance of weed biotypes to triazine herbicide is not mainly due to limited absorption and translocation or to the difference in metabolism, but is the result of biochemical changes at the site of metabolic activity, such as a loss of herbicide affinity for triazine binding site in the photosystem II complex of the chloroplast membrane. Genetical study showed that plastid resistance to triazine was wholly inherited through cytoplasmic DNA in the case of Brassica campestris. Plant tissue culture method can be utilized as an alternate mean of herbicide screening and development of resistance variants to herbicides as suggested by Chaleff and Parsons. In this purpose, one should be certain that the primary target process is operational in cell culture. Further, there are a variety of obstacles in doing this type of research, particularly development of resistance source and it's regeneration because cultured cells and whole plants represent different developmental state.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.219-223
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• 1991

Effects of media and low temperature on germination of weeds were examined to get basic information for establishing weed control methods. Soil and agar(0.4%) was good media for germination of weeds at laboratory. Germination was improved by placing weed seeds at 5$^{\circ}C$ low temperature for 10-20 days. Germination was improved by storing weed seeds in water absorbed gauge and in vinylbag at 5$^{\circ}C$ low temperature for 30-40 days. Germination was increased by burial of weed seeds at 10cm of soil depth for 30-60 days.

• Weed & Turfgrass Science
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• v.5 no.2
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• pp.60-64
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• 2016

Investigation on weed flora in Lycium chinense upland fields was conducted to understand the current status of weed flora and establish the control measures. Investigation was conducted twice, May and June on 2015. From this investigation, 91 species of 30 families including 27 exotics were identified into 36 species of annuals, 28 species of biennials and 27 species of perennials. Dominance was the highest with Portulaca loeracea followed by Digitaria ciliaris, Stellaria media, Oxalis corniculata, Acalypha australis, Chenopodium album, Cyperus iria etc. in order. Chenopodium album was the highest in importance analysis and the followings were in order of Conyza canadensis, Conyza bonariensis, Senecio vulgaris, Amaranthus lividus, Sonchus asper etc.

• 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.

• 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.

• Weed & Turfgrass Science
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• v.4 no.3
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• pp.209-218
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• 2015

This study was conducted to investigate the weed occurrence and distribution on the upland crop fields (garlic, barley, potato, maize, red pepper, soybean and Chinese cabbage) at 795 sites in Chungbuk province of Korea from Apr. to Oct. in 2014. From the result of this survey, 188 weed species in 42 families were identified and classified to 96 annuals, 40 biennials and 52 perennials. Based on the occurrence ratio, the most dominant weed species in Chungbuk province upland crop fields were higher in the order of Portulaca oleracea (8.14%), Digitaria ciliaris (6.72%), Echinochloa crus-galli (6.55%), Rorippa palustris (6.00%) and Chenopodium album (5.89%). The composition of major occurred weed families, Compositae, Poaceae, Polygonaceae and Cruciferae were 19, 10, 7 and 6%, respectively. In the winter upland crop fields, the dominant weeds were in the order of Capsella bursa-pastoris (12.36%), Alopecurus aequalis (11.05%) and Stellaria alsine (8.42%). In the summer upland crop fields, the dominant weeds were in the order of Portulaca oleracea (8.58%), Digitaria ciliaris (7.18%) and Rorippa palustris (6.28%). Fiftythree exotic weed species were identified. The results of this study could be useful information for estimation of future weed occurrence, weed population dynamics and establishment of weed control methods on the upland crop fields in Chungbuk province of Korea.

• Korean Journal of Weed Science
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• v.31 no.2
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• pp.167-174
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• 2011

Weed control using cover crops has advantages of agricultural and environmental aspects which prevent soil erosion, nitrogen supply, improving soil physical properties, reduction of nitrate leaching, organic supply and control of weed occurrence. In this study, we evaluated the inhibitory effects of cover crops on the weed occurrence, growth and yield of soybean in cover crop-soybean cropping system. The treatments were consisted of 4 different mulching system such as crimson clover (Trifolium incarnatum) residue, hairy vetch (Vicia villosa) residue, rye (Secale cereale) residue and Polyethylene plastic(P.E.) mulch with no mulch treatment (control). Three cover crops were grown throughout the winter and were cut in next spring. And then 13 days old soybean seedlings were transplanted in each treatment field on $4^{th}$ June. Crimson clover, hairy vetch and rye mulch treatments reduced weeds density compared to control (73.0%, 98.0% and 85.3% respectively), on $26^{th}$ May. However, weed inhibition rate of crimson clover mulch treatment was sharply decreased to 4.17% on $6^{th}$ August, while hairy vetch and rye mulch treatments were continued high weed inhibition rate with 87.6% and 72.0% respectively. There was no inhibition effect of perennial, winter annual and broadleaf weeds inhibition in crimson clover mulch treatment. Height of soybean in crimson clover, hairy vetch and P.E. mulch treatment was 6.9%, 20.2% and 22.0% higher than that of control. But height of soybean in rye mulch treatment was lower than control on $13^{th}$ July. At harvesting, yields of soybean were in order of hairy vetch mulch treatment${\fallingdotseq}$ P.E. mulch treatment > crimson clover mulch treatment ${\fallingdotseq}$ rye mulch treatment > control.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.159-166
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• 1991

Seven oxyfluorfen formulations were tested for control of 8 weed species and rice injury under four different water depths with various ages of rice seedlings. Among formulations tested, rice injury was slight by formulations of Elvan, Coal Slag, Chitosan and Bentonite B under 0 cm or shallow water depths, and by those of Elvan and Coal Slag under deep water conditions. Weed control was high by Bentonite A and B, and Chitosan, and was low by Elvan. Coal Slag and Sand coated oxyfluorfen, if the target weeds of oxyfluorfen are annual species, further development of Elvan, coal slag, chitosan and Bentonite A would be controlled to increase control efficacy or to decrease rice injury.