• Korean Journal of Weed Science
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• v.4 no.2
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• pp.204-210
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• 1984

For weeding on the after-barley cropping soybean, the tank-mix use of postemergence herbicides acifluorfen and haloxyfop-methyl was tested. Acifluorfen has shown the transient leaf-burn on the newly formed soybean leaves, but no growth inhibitions. Under the treatment of acifluorfen only, grassy weeds occurred successively and explosively. However, under the combinated spraying of both herbicides, the grassy weeds could be controlled in a slight antagonistic, the broadleaved weeds in additive, and the total weed species including sedges in synergic tendencies, respectively. Also, to achieve the full-season weeding efficacies for the prominent crop yields, both herbicides are suggested to be mixed with more dosages than 0.245 kg ai/ha of acifluorfen and 0.15 kg ae/ha of haloxyfop-methyl, respectively.

• Korean Journal of Weed Science
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• v.1 no.1
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• pp.52-56
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• 1981

A 2-year field experiment was conducted to determine the influence of early and late soybean (Clycine max Merr) seeding times on competitive relationships between soybeans and annual weeds. Soybeans were planted on May 20 and June 20. Durations of weed competition and weed control were 0, 3, 6, 9, and 12 weeks after planting sad for full growing season. Dominant weeds were Portulaca oleracia, Centipeda minima, Rorippa cantonienais, Chenopodium album, Acalypha australis, Echinochloa crusgalli, and Digitaria sanguinalis. The dry weight of weeds increased with extended competition, especially at early seeding time of soybeans. Soybean yields were decreased as duration of weed competition was extended. More severe yield reduction occurred at late-planted soybeans with early stage weed competition but at early-planted soybeans when weeds competed with soybeans for a 2 weeds and full growing season. The dry weight of weeds emerged after weeding was decreased at early and late seeding times of soybeans as duration of weed control was prolonged. Soybean yields decreased with shortening duration of weed control end this trend of yield reduction was slightly more remarkable at late-planted soybeans than at early-planted soybeans. Late-planted soybeans were required longer than 6 weeks of weed control period to achieve maximum yield as compared to early-planted soybeans.

• Korean Journal of Weed Science
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• v.8 no.3
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• pp.258-264
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• 1988

Phenolic compounds present in upland weeds (Artemisia asiatica Nakai, Capsella bursa-pastoris (L.) Medik, Portulaca orleracea L. and Trifolium repens L.) which have shown allelopathic activity were determined using paper chromatography (PC) and high performance liquid chromatography (HPLC). Effect of the determined phenolic compounds on germination and post-germination growth of test plants was also investigated. Kinds of phenolic compounds determined by PC in the four weed species were greater in the aqueous extract than in the methanol extract. Ferulic acid was found in both extracts of the weeds studied, whereas benzoic acid was that the weeds commonly contained hydroquinone, p-hydroxybenzoic, ferulic and cinnamic acids. Out of the phenolic compounds determined by PC and HPLC p-hydroxybenzoic, cinnamic and ferulic acids inhibited germination and post-germination growth of radish and sesame. Inhibition of the phenolic compounds on the radicle growth was greater than on the germination of the test plants.

• Korean Journal of Weed Science
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• v.4 no.2
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• pp.163-168
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• 1984

This study was conducted to find out the effect of paclobutrazol 0.6G and flurprimido 50wp application at 40 days before heading on the characters related with lodging and the growth and yield of paddy rice plants in 1983. The culm length were shortened by paclobutrazol and flurprimido applications and high level of suppression was observed in the 3rd to 5th internodes. Paclobutrazol caused thiner internode and thicker wall of internode than the untreated control, however flurprimido caused thicker wall of internode without change of internode diameter. The breaking weight of lower internode was higher by flurprimido application than those by the untreated control and paclobutrazol application. The lodging indexes effected by both chemicals were remarkably decreased, and also the field lodging was not observed. The leaf area indexes effected by paclobutrazol and flurprimido applications were increased because of the increasing of tillers and green leaves per stem in spite of shortening of lead blades. Paclobutrazol and flurprimido application out-yielded significantly the untreated control lodged at grain filling stage. However in conditions of untreated with no lodging, the yields of these treatments were significantly less than that of untreated control.

• Korean Journal of Weed Science
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• v.16 no.4
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• pp.282-291
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• 1996

This experiment was conducted to investigate the phytotoxicity of several herbicides for rice and weed control with herbicides application times and seeding times in flooded direct-seeded rice field. The phytotoxicity of herbieides(bensulfuron methyl+dimepiperate, bensulfuron methyl+mefenacet+dymron, bensulfuron methyl+quinclorac, pyrazosulfuron-ethyl+molinate, pyrazosulfuron-ethyl+thiobencarb, pyrazosulfuron-ethyl+cyhalofop, imazosulfuron+molinate, imazosul-furon+cyhalofop) for rice in different seeding dates was the most high at 7 days after seeding(DAS) Followed by 12 and 17 DAS. In particular, the bensulfuron methyl+mefenacet+dymron showed very high phytotoxicity to rice plants. Weed species occurred in direct-seeding field seeded on May 1 were 10 species (grasses ; 1, broad-leaves ; 6, sedges ; 3) and Echinochloa crus-galli was the most dominant weed among them. Whereas weed species occurred rice field seeded on May 22 were 7 species(grasses ; 1, broad-leaves : 3, ridges ; 3) and Echirochloa crus-galli was the most dominant weed among them. The weed control for annual weeds(Echinochloa crus-galli, Aneilema keisak, and so on) and perennial weeds(Cyperus serotinus, Scipurus juncoides) was remarkably effective at the application of 7 and 12 DAS, but it of Eleocharis kuroguwai was effective at the application of 17 DAS on two seeding times. The yields were decreased significantly at the plot affected severely by herbicides applied at 7 DAS and the plots showed low efficacy at herbicides application of 17 DAS.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.243-251
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• 2010

The study was conducted to evaluate the weed suppressing effects of two winter cover crops, Chinese milk vetch (CMV) and rye, in minor cereal fields in 2009. The suppressing activities of cover crops were due to the allelopathy of cover crops during weed emerging periods and competitive activity during vegetative growth of weeds. Weed suppression by cover crops were changed from 26.5 g $m^{-2}$, 0.1 g $m^{-2}$ and 0.2 g $m^{-2}$ in control, rye field and CMV field, respectively, on June 22 to 428.6 g $m^{-2}$, 1 g $m^{-2}$ and 403.9 g $m^{-2}$ in control, rye field and CMV field, respectively, on July 22. The weed dry weights were further changed to 656.3 g $m^{-2}$, 607.8 g $m^{-2}$ and 511.8 g $m^{-2}$ in control, rye field and CMV field, respectively, on August 22. The suppressing effect of cover crops also observed in minor cereals. Plant height and dry weight of sorghum was reduced to 68.7% and 33.6% of handweeding, respectively, on August 5. The reduction was recovered to 82.7% and 55.6% of control, respectively, on August 26. In addition, heading date of minor cereals was delayed by 7 days with rye.

• Weed & Turfgrass Science
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• v.3 no.1
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• pp.13-18
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• 2014

This study was conducted to develop an eco-friendly control method for water foxtail in the field sowing barley seeds before rice harvesting. When sea water was applied pre-emergent, 1 and 2 leaves, little injury was observed on barley. Percent of water foxtail control with sea water (100%) was more than 50% at 1 leaf application timing. When sodium chloride was applied 400, 800 and $1,600kg\;ha^{-1}$, little injury was observed on barley. Percent of water foxtail control with sodium chloride was 36-44% at 30 days after sowing. When ferrous sulfate was applied at 400, 800 and $1,600kg\;ha^{-1}$, emergent injury was observed 35-50% on barley. Percent of water foxtail control with ferrous sulfate was 48-79% at 30 days after sowing. When barley was sowed at 200, 300 and $400kg\;ha^{-1}$, seeding rate standing plants have many of the more crops, water foxtail occurrence was low. And, Forage yield of 300 kg ha-1 seeding in the highest. Based on the results, it is possible to control water foxtail in the field sowing barley seeds before rice harvesting more than 50%.

• Weed & Turfgrass Science
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• v.6 no.2
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• pp.124-129
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• 2017

The Experiments were conducted by moderate season culture of each of early, medium and late maturing varieties which were considered to be of strong salt tolerance in low and high salty reclaimed areas (0.2% at the May). This study was carried out to investigate the proper nitrogen fertilizer level and seeding rates at reclaimed saline land in Korea. The proper seeding rates were $40kg\;ha^{-1}$ in 0.2% saline land. The dry matter production of barnyard millet was possibly estimated by exponential functions of $Y=0.0098X^2+0.7030X+2.6267$. Effects of nitrogen rate on agronomic characteristics, forage yield, and chemical composition of barnyard millet to reclaimed tidal land are summarized as follows: The proper nitrogen fertilizer level was $200kg\;ha^{-1}$ in 0.2% saline land. N was absorbed actively before the emergence of the barnyard millet but showed relative decrease thereafter. The early growth of the barnyard millet was inhibited, resulting in the favorable late growth, increased panicle weight and ratio of matured grain. These results suggest that barnyard millet is the most forage crops for cultivation on reclaimed tideland in view of the good emergence and forage production.

• Korean Journal of Weed Science
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• v.9 no.2
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• pp.90-96
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• 1989

This experiments were conducted to investigate the effect of plant growth regulator treatments on the ethylene evolution in soybean sprouts. Major results can be summarized as follows. 1. IAA showed no significant effect on the ethylene evolution in soybean sprouts. 2. BA increased significantly ethylene evolution while kinetin, zeatin, zeatin riboside were less effective on the ethylene production in soybean sprouts. 3. As the BA concentration was increased, the ethylene evolution was increased. 4. BA increased ethylene production more effectively at earlier stages while 4PU-30 was more effective for ethylene production rather continuously. 5. The order of effectiveness of cytokinins and auxin on the ethylene evolution was as follows : BA 25 ppm>BA 25ppm+IAA 25ppm${\geq}$4PU-30 25ppm>IAA 25ppm>control. 6. It can be concluded that BA was the most effective in inhibiting lateral roots, among the cytokinins tested, and resulted in the biggest diameter of hypocotyl by the ethylene evolution stimulated by BA treatment.

• Korean Journal of Weed Science
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• v.9 no.2
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• pp.141-148
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• 1989

Echinochloa species collected from 13 places of Korea appeared to be morphologically very different. They were classified by Yabuno's seed morphology method into two species such as Echinochloa oryzicola and Echinochloa crus-galli which have two varieties such E. crus-galli var, cuss-galli and var, praticola. Among them, E. oryzicola was morphologically similar to Oryza sativa, but it had small leaf length with straight from, no awn, late heading and little interspecific variance. As compared with E. oryzicola, E. eras-galli var. crus-galli, and var, praticola showed a great variance exerting so difficulty in classifing them morphologically, particularly a great variance in leaf length, tiller number and grain size. E. oryzicola species showed the more sensitive response to butachor and thiobencarb herbicides than E. eras-galli var. praticola and var. eras-galli. However, E. eras-galli var. praticola was themore sensitive one to pretilachloa herbicide than such as E. oryzicola and E. eras-galli var. eras-galli, indicating that Echinochloa species might have a selective response to the annual herbicides tested.