• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.564-570
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• 1997

Field experiments were carried out to investigate the effects of different residue treatment of vetch sward on soil improvement, rice growth and grain yield from 1995 to 1996. With Chinese milkvetch, pH, Ca, and Mg of paddy soil were increased in subsoil(10~20cm soil depth), and organic matter, P$_2$ $O_{5}$, and K were increased in top soil (0~10cm soil depth). Redox potential of the paddy soil with milkvetch residue was severely reduced at earlier flooding period, and recovered gradually as rice growth continued. Weeds were more abundant in the paddy with unchanged vetch stand. The most dominant weed species in the paddy soil with vetch sward residue was Echinochloa crus-galli, followed by Leersia japonica, Polygonum hydropiper in the order of abundance. Seedling establishment ratio of rice directly sown over vetch-sward was lower than in conventional tillage paddy(no-vetch, tilled) condition. Rice growth pattern, however, was not significantly affected by vetch sward treatments. The number of tillers per square meter and plant height at heading date were not significantly different among the vetch-sward treatments. Grain yield was the highest in plough of vetch vegetation, followed by conventional (no-vetch, tilled), live-mulching of vetch, vetch-removed, and vetch-desiccated by weedcide. The whole grain rice yield was the lowest in vetch-desiccated by weedcide.

• Korean Journal of Weed Science
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• v.32 no.2
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• pp.121-126
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• 2012

National Academy of Agricultural Science and eight province Agricultural Research & Extension Services investigated the occurring area of herbicide resistant weeds in paddy field of Korea. In order to estimate the occurring areas of herbicide resistant weeds, we collected paddy soils on August, 2011 and treated 30kg $ha^{-1}$ of pyrazosulfuron-ethyl+pyriminobac-methyl GR. 167,081ha, approximately 20.9% of cultivated area excluding organic and eco-friendly cultivated area, was estimated to be infested by SU-herbicide resistant paddy field weeds. It was increased by 60,130ha compared with investigation of 2008. It was occurred at Chungchungnam-do by 47.6%, followed by 36.9% at Jeonranam-do, 25.7% at Chungchungbuk-do, 20.5% at Gangwon do, and 13.0% at Gyeonggi-do, respectively. Monochoria vaginalis showed the highest with 65,313ha, 39.1% followed by Scirpus juncoides, and Cyperus difformis, respectively. These three species were evenly distributed and the most problematic weeds in the country. Lindernia dubia occurred at 13,964ha (8.4%) and Echinochloa oryzicola was 5.1%, respectively.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.208-219
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• 1987

Newly developed several herbicides were evaluated as paddy rice herbicide at the Yeongnam Crop Experiment in 1986. And also, the general situation of rice cultivation between Korea and Japan was compared. Twenty-nine herbicides of the total 59 herbicides were used as paddy rice field in Korea while these were 100 and 187, respectively, in Japan. Among paddy rice herbicides, butachlor was the most important herbicide in both countries. However, the degree of concentration to a particular herbicide was greater in Korea compared to Japan; consumption rate of single butachlor to the total herbicide were 66.5% for Korea and 11.9%r for Japan, respectively. Pyrazolate, pyrazoxyfen and quinclorac were the most promising hebicides in pressed-type rice nurserybed in terms of herbicidal efficacy and phytotoxic effect. For transplanted paddy rice field, single application of NC-311 or combining applications of NC-311 with butachlor or quinclorac gave excellent results at the weed community that was dominated by Echinochloa crus-galli, Aneilema japonica, Ludwigia prostrata, Scirpus hotarui, Cyperus serotinus, Potamogeton distinctus and Eleocharis kuroguwai. Particularly the above combining applications maintained their excellent herbicidal effect up to 3 leaf stage of E. crus-galli without arising herbicidal phytotoxicity. Pyrazolate and three sulfonyl urea herbicides (DPX-5384, NC-311 and CGA 142464) exhibited very high safety against rice. However, Japonica type rice cultivar was a little bit more sensitive than Indica/Japonica type rice cultivar. On the other hand, the effect of these herbicides against E. crus-galli was very strong. Herbicidal effect against E. crus-galli was enhanced through shoot absorption for sulfonyl urea herbicides and root abosorption for pyrazolate and quinclorac, respectively.

• Korean Journal of Weed Science
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• v.6 no.1
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• pp.48-58
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• 1986

In order to eluciate the factors affecting the injury caused by simetryne(2-methyl thio-4,6-bis(ethylamino)-S-triazine) to rice plants of Tongil variety(Indica ${\times}$ Japonica), the leaching properties of simetrynes, compared with Japonica varieties, Mangyeung and Sadominori were investigated. Bioassay technique and $^{14}C$-simetryne for leaching study and bioassay for the characteristics of the rice plants were employed. The leaching range of simetryne was very narrow regardless of soil types under upland soil conditions but it increased little in Silt clay soil and greatly in Sandy loam soil under flooded soil conditions. The amount of the roots of Tongil Jas a little more than that of Mangyeung and the roots of the Tongil mostly distributed near the surface soil while those of Mangyeung rooted deep into the soil. The foliage area and the rate of transpiration of Tongil were larger and greater than those of Mangyeung by 1.3 times and 1.65 times, respectively. The sensitivity of Tongil to simetryne was about 3 times larger than that of Sadominori in water culture.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.230-236
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• 1996

Pot experiment in greenhouse was conducted to determine the effect of growth and anatomical characteristics of bensulfuron on the seedlings of rice and barnyardgrass. Formulated bensulfuron was soil applied at 102g ai/ha to rice and barnyardgrass grown under various cropping patterns at 5 days after seeding or transplanting. At 10 days after application, plants were harvested to examine growth and anatomical changes of rice and barnyardgrass. Bensulfuron did not affect the growth and development of rites under dry seeded condition and trnsplanting condition while inhibited severely those of rice under water-seeded condition compared with untreated control. Under water-seeded condition, root growth of rice was much more severely inhibited by bensulfuron than shoot growth. The herbicide retarded the growth of barnyardgrass under dry-seeded condition and more severely inhibited than that under water-seeded condition. Microscopically, the anatomical change induced by bensulfuron occurred only in barnyardgrass under dry-seeded condition, and involved constriction of leaf primordia within leaf sheaths, rupture of mesophyll cell, and irregular cell arrangement. These anatomical alterations differed from and were not associated with the differential growth response.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.57-69
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• 2012

This study was conducted to find the effective management of main weeds including herbicide-resistant Echinochloa oryzicola, Scirpus juncoides and Monochoria vaginalis in direct seeded rice on puddled paddy surface. The dominant dominances in direct seeded rice on puddled paddy surface were increased for three years between 2009-2011. In weed distribution in 2011, the occurrence density of S. juncoides decreased greatly, but it of E. oryzicola increased especially as compared with it of 2009. Benzobicyclon, mesotrione and pyrimisulfan were effective to sulfonylurea(SU)-resistant S. juncoides and M. vaginalis at 5 and 12 days after seeding, however, the efficacy of bromobutide to sulfonylurea-resistant M. vaginalis was decreased slightly at 12 days after seeding. And carfentrazon and pyrazolate were ineffective to S. juncoides. In direct seeded rice on puddled paddy surface which ACCase and ALS inhibitor-resistant E. oryzicola was not occurred, benzobicyclon+penoxsulam+pyrazosulfuron-ethyl ET, bromobutide+imazosulfuron+metamifop GR, and flucetosulfuron+mesotrione+pretilachlor GR showed the control effect over 94% to main weeds included sulfonylurea-resistant S. juncoides and M. vaginalis. The E. oryzicola dominating in direct seeded rice on puddled paddy surface were not any affected to the survival by treatment with recommended doses of cyhalofop-butyl and penoxsulam tested. The ACCase and ALS inhibitor-resistant E. oryzicola was effectively controlled by mefenacet and fentrazamide up to the 2nd leaf stage. In direct seeded rice on puddled paddy surface domiating coincidentally by herbicide-resistant E. oryzicola, S. juncoides and M. vaginalis, "one-shot herbicide" included with mefenacet, fentrazamide, penoxsulam and metamifop could't be used because of low control effect or rice injury. The sequential treatment of benzobicyclon+thiobencarb SE and bensulfuron+mefenacet+thiobencarb GR controlled effectively the herbicide-resistant E. oryzicola, S. juncoides and M. vaginalis in direct seeded rice on puddled paddy surface. The days required by the 3rd leaf stage of herbicide-resistant E. oryzicola, S. juncoides and M. vaginalis in direct seeded rice on puddled paddy surface seeded in May 20 shortened by 4 days as compared with it of June 10.

• Korean Journal of Weed Science
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• v.14 no.2
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• pp.107-111
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• 1994

Selective action of root-treated oxyfluorfen [(2-chloro-4-thrifluoromethylphenyl)-3'-ethoxy-4'-nitrophenyl ether] and chlomethoxynil [2, 4-dichlorophenyl-3'-methoxy-4'-nitrophenyl ether] were investigated. Oxyfluorfen showed greater activity to all plant species than chlomethoxynil. $^{14}C$-oxyfluorfen was little metabolized in roots of the plant species and more slowly absorbed than $^{14}C$-chlomethoxynil. These results suggest that herbicidal activity of oxyfluorfen at the site of action is higher than chlomethoxynil. In the tested plants, rice, barnyardgrass, sorghum, and corn were absorbed less of the oxyfluorfen and chlomethoxynil than the broad leaf plant species. However, no clear relationship was observed between a degree of tolerance and absorption and metabolism of both herbicides by the plant species.

• Korean Journal of Weed Science
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• v.5 no.1
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• pp.56-62
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• 1985

Effects of butachlor [N-(butoxymethyl)-2-chloro-2', 6'-diethyl acetanilide] and 1,8-naphthalic anhydride (NA) on post-germination growth, mesocotyl and root anatomy and root-cell membrane permeability of rice (Orvza saliva L.) were investigated. Lengths of mesocotyl and radicle were markedly decreased as the application rates of butachlor increased from 0.1 to 100 ppmW and NA from 1 to 100 ppmW, but there was no effect on coleoptile elongation. Application of butachlor-NA resulted in increase in coleoptile elongation, but decrease in mesocotyl elongation. Partial breakdown of cortical cells in root and mesocotyl was caused by either trutachlor or NA treatments, resulting in increase in intercellular air space. Further increase in the intercellular air space of root and mesocotyl was obtained when butachlor was applied in combination with NA. Increase in root-cell membrane permeability occurred when either butachlor or NA was applied. However, butachlor-NA treatments resulted in reduction in the permeability.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.187-194
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• 1991

Absorption and translocation, and metabolism studies using $^{14}C$-naproanilide were conducted to determine selective mode of action of naproanilide in rice and paddy weeds under different temperature conditions. Absorption amount of $^{14}C$-naproanilide was greater in Cyperus serotinus and Sagittaria pygmaea than rice and Echinochloa crusgalli. Especially, absorption of $^{14}C$-naproanilide in C. serotinus was increased twice at 32 $^{\circ}C$ and 48 hour exposure conditions. $^{14}C$-naproanilide in roots was translocated to shoots very little in rice and E. crusgalli, but S. pygmaea somewhat greater translocation than the other species. In C. serotinus and S. pygmaea, susceptible weeds, metabolic rates of naproanilide into phytotoxic NOP (2-(2-naphthoxy)-propionic acid) and NOPM (methyl 2-(2-naphthoxy) propionate) were significantly greater than in rice and E. crugalli, tolerant species. Consequently, differential uptake by roots and the difference in activation metabolism of naproanilide among species may explain the possible mechanism of selectivity.

• Korean Journal of Weed Science
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• v.10 no.3
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• pp.171-178
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• 1990

This study was conducted to determine which of the different agronomic traits of rice (Oryza saliva L.) has greater weight in predicting thiobencarb (S-[(4-chlorophenyl) methyl]diethylcarbamothioate) tolerance. Differences in plant height, tiller number, culm length, panicle number, and spikelet number per panicle between tolerant and susceptible cultivars were greater at the higher herbicide rate. However, days to heading and percent filled spikelets were not affected by herbicide rate. At the higher thiobencarb rate, the coefficients for all characters except plant height, tiller number, and percent filled spikelets were significant. Spikelet number per panicle and panicle number which had positive significant coefficients at both concentrations are the most useful indicators of total filled spikelets.