• Journal of Korean Society of Environmental Engineers
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• v.30 no.5
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• pp.500-506
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• 2008

Enhanced phytoremediation with EDTA or PSM(Phosphate solubilizing microorganism) was studied using green foxtail (Setaria viridis) in columns packed with 1,200 mgPb/kg contaminated soil to investigate the effects of EDTA or PSM on the plant uptake and vertical migration of Pb. EDTA, equimolar amount of total Pb in the column soil, was administered in two methods: the one was treated with 1/6 aliquots of the equimolar EDTA every week for 6 weeks and the other was treated with single dose of the equimolar EDTA before 14 days of harvest. The results showed that higher concentrations of Pb accumulated in the biomass of green fowtail after the chemical or biological treatment. The plant-root Pb concentration in PSM treatment(M), EDTA aliquot treatment(ES), and single dose treatment(E) was 2.6, 3.0, and 3.3 times higher, respectively, than that in the plant-root of control(164.7 mg/kg). The plant-stem Pb concentration in the M, ES and E treatment was 27, 37, and 40 times higher than that in the stem of control(8.1 mg/kg). The translocation factor, the ratio of shoot/root Pb concentration, was 0.6 in the two EDTA treatment, 0.5 in the M treatment, and 0.05 in the control, respectively. The largest amount of Pb was phyto-extracted in the E treatment whereas vertical migration of EDTA was significant in the ES treatment. This result showed that a single large dose of EDTA before harvest serves better for enhanced phytoremediation of Pb. Although, treatment with PSM showed less Pb phytoextraction by the plant but enhanced both the growth of plants in the column and microbial dehydrogenase activity in the soils. Therefore, enhanced phytoextraction of Pb with PSM treatment can be an alternative option for EDTA treatment, which is toxic to plants and soil ecosystem.

• Korean Journal of Weed Science
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• v.9 no.2
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• pp.130-140
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• 1989

1) Dormancy brocken weed seeds were planted in soil at 15 days interval from June to December in 1986 and 1987 and test of normality and normal distribution curve were made to determine seasonal distribution characteristics of weed emergence in fields. Monthly emergence distribution pattern of each species can be concluded as following normal distribution equations. E. crusgalli $y={\frac{1}{2.52{\sqrt{2{\pi}}}}}e^{-{\frac{(x-10.057)^2}{12.7}}}$ E. indica $y={\frac{1}{2.17{\sqrt{2{\pi}}}}}e^{-{\frac{(x-9.16)^2}{9.45}}}$ A. lividus $y={\frac{1}{7.74{\sqrt{2{\pi}}}}}e^{-{\frac{(x-10.06)^2}{15.46}}}$ S. nigrum $y={\frac{1}{2.7{\sqrt{2{\pi}}}}}e^{-{\frac{(x-9.695)^2}{14.58}}}$ C. busrsa-pastoris $y={\frac{1}{2.83{\sqrt{2{\pi}}}}}e^{-{\frac{(x-9.02)^2}{16.02}}}$ D. sanguinalis $y={\frac{1}{2.8{\sqrt{2{\pi}}}}}e^{-{\frac{(x-8.58)^2}{15.67}}}$ S. viridis $y={\frac{1}{2.72{\sqrt{2{\pi}}}}}e^{-{\frac{(x-9.36)^2}{14.8}}}$ C. album $y={\frac{1}{2.596{\sqrt{2{\pi}}}}}e^{-{\frac{(x-8.07)^2}{13.48}}}$ P. oleraeda $y={\frac{1}{2.45{\sqrt{2{\pi}}}}}e^{-{\frac{(x-10.83)^2}{12.01}}}$ 2) Emergence peak period of weed species tested were from the end of May to early August and yearly variation of emergence was observed in E. crus-galli, S. viridis, S, nigrum, and P. oleracea and this fact may more related to rainfall pattern rather than temperature.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.447-453
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• 2009

Vegetation distribution and soil salinity were surveyed on the conservation plot in the Daeho reclaimed tidal land, in where the plants species distribution was more various than a periodically inundated tidal flat and the early stage of reclamation. According to the soil salinity where the vegetation patches were occurred, the mono patches of Salicornia europaea, Suaeda maritima, and Suaeda glauca were distributed in the average range of 31.05 dS/m in soil salinity, the mixed patches of them were distributed in the average range of 42.75 dS/m. Therefore, Salicornia europaea, Suaeda maritima, and Suaeda glauca showed strong salt tolerance. The mono patches of Aster tripolium, Sonchus brachyotus, and Scirpus planiculm were distributed in the range of 11.73 dS/m in soil salinity, and the mixed patches were distributed in the average range of 9.43 dS/m. Therefore Aster tripolium, Sonchus brachyotus, and Scirpus planiculmis showed moderate salt tolerance. The mono patches of Imperata cylindrica, Trifolium pratense, Miscanthus sinensis, Setaria viridis, and Trisetum bifidum were distributed in the range of 2.42 dS/m in soil salinity. These species showed characteristics of glycophytes with weak salt tolerance. The distribution of vegetation patches was influenced by the soil salinity as pioneer halophytes patches occurred at higher soil salinity zone than facultative halophytes patches, glycophytes patches occurred at lower soil salinity zone than facultative halophytes. These results suggested that occurrence of plant species and plant distribution type might be useful index to evaluate the soil salinity and desalinization in the reclaimed land of the midwest coastal area of Korea.

• Korean Journal of Environmental Agriculture
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• v.22 no.1
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• pp.53-59
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• 2003

The present study was conducted to analyze the vegetational difference in fellowed fields at the different seral stages. Plant species were surveyed on the fields having different cropping history, soil moisture conditions, and the duration of set-aside. Effects of soil moisture condition and fellowing duration on the vegetational profiles of fellowed fields in the course of different seral stages. In the fields fellowed for more than three years, a conspicuous feature of vegetation was the dominance of perennial species, which was less dominant in the fields fellowed for less than 3 years. The floristic composition of fellowed fields was dependent on the soil moisture condition. However, the influence of fallow-history on vegetational composition was less than that of the soil moisture conditions. The dominant species occurred in fellowed upland (dry) fields were changed from Glycine soja, Persicaria thunbergiana, and Artemisia princeps at 2-year-fellowed to Persicaria thunbergiana, Miscanthus sinensis, and Glycine soja at 6-year-fellowed. In wet fellowed paddy fields, annual Mosla punctulata, Ambrosia artemisiifolia, and Setaria viridis, the dominant species at 3-year-fellowed, were substituted by perennial Miscanthus sinensis, Aster pilosus, and Hemarthria sibirica at 7-year-fellowed. When the succession continued for 11 years in wet fields, the vegetation was characterized by the domination of perennials such as Phragmites communis, Zizania latifolia, and Typha orientalis. It was suggested that the soil moisture condition was a strong determinant of the dominant species on early seral conditions. In the fellowed paddy fields, the species diversity was relatively higher in the fields set-asided as wet condition compared to the fields fellowed as dry condition.

• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.364-369
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• 2000

In order to obtain the reference data to be used as an vegetation index for degree of desalinization, vegetation successions were surveyed and soil chemical characteristics were analyzed at the naturally maintained plot in Dae-Ho reclaimed land. Seven Groups $(A\;{\sim}\;G\;group)$ were classified as major vegetation; A group (Suaeda asparagoides MAKINO etc.), B group ( Aster tripolium L. etc.), C group (Stearia viridis L. BEAUV), D group ( Phragmites longivalvis STEUD), E group (Limonium tettagonum THUMB A. A. BULLOCK), F group (Trifolium repens L.), G group (Zoysia sinca HANCE etc.). As desalinization process proceeded, the wild vegetation changed in order of $A\;{\to}\;B\;group$, $D\;{\to}\;C\;group$, $E\;{\to}\;F$, G group. Soil texture of the naturally maintained plot was silt loam and soil fertility was very low compared with agricultural cultivated soil. Soil pH ranged from 7.0 to 8.0. Electrical conductivity (ECe) was below 10 and $20\;dS{\cdot}m^{-1}$ at top and subsoil, respectively, except the plot where A group were growing. Resulting from SAR and ECe, The plot where A group was growing was saline-sodic soil and the others were saline soil. The relation between vegetation sucession and soil desalinization showed that vegation appeared under $10\;dS{\cdot}m^{-1}$ of ECe and 15 of SAR except A group.

• Journal of environmental and Sanitary engineering
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• v.5 no.2
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• pp.105-116
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• 1990

Seungbong Island is situated about 100km away Inchon Port in the western sea of the Korean Peninsula. Field investigations were conducted for two days each from June 30 through July 1, 1981 and from August 20 through 21, 1981. The results obtained are summarized as follows: Plants growing in this island consist of a total of 193 species (70 families, 151 genera, 170 species, 22 varieties and 1 forma). Pinus thunbergii was confirmed to be the dominant species. The natural degree observed in this island was high, as a whole. The coefficient of ferny plants (Pte-Q) is 0.95, lower than grass. Atractylodes japonica Koidz., Miscanthus sinensis Anders. var. purpurascense Rendle, and Rhododendron mucronulatum Turz. are distributed mainly on the forest bed of Pinus thunbergii. The poor distribution of Chenopodium album var. centrorubrum Makino, Setaria viridis (L.) Beauv., Amaranthus mangostanus Linne is considered attributable to the phenomenon of allellopathy caused by a chemical substance secreted from the leaves of Pinus thunbergii. The component ratio of species in this island is lower than that of other islands due probably to the small area of arable land and grassland. The poor growth of plants in the forest of Pinus thunbergii, the dominant species in this island, seems to be attributed to the low relative light intensity of the forest. Seaside plants consisting of a total of 7 species were distributed mainly in the vicinity of sandy beaches. Naturalized plants comprising a total of 11 species were relatively diversified in the number of species.

• Korean Journal of Weed Science
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• v.11 no.1
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• pp.3-10
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• 1991

Several rice herbicides were evaluated to determine the herbicidal efficacy on dry seeded paddy rice. The time of herbicide application was within 1 day after seeding(DAS), 18 DAS, and 40 DAS. Under the upland conditions 30 DAS(before permanent flooding) dominant weed species were Echinochloa sp., Digitaria sp., Leptochla sp., weedy rice and other several annual broadleaved weeds belonging to Cruciferae, but after flooding Echinochloa sp., Aeschynomene sp., Eleocharis kuroguwai, Cyperus sorotinus, Ludwigia prostrata, Aneilema japonica were dominat. Early application (1 DAS) of thiobencarb, pyrazolate/butachlor, or chlomethoxyfen/butachlor resulted in very good herbicidal efficacy only during the first 30 days, but not thereafter. Application of propanil+butachlor on 18 DAS did not control the late occurring weeds effectively. Application of bentazone/quinchlorac on 40 DAS successfully suppressed weed growth throughout the remaining rice growing season and showed similar grain yield as hand weeded plot. Weed growth reduced the plant height, panicle number, 1000-grain weight, percent ripened grains, and grain yield of rice by 7, 82, 19, 55 and 87% respectively. There was a positive linear relationship between weed weight and lodging index of rice.

• Korean Journal of Weed Science
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• v.17 no.3
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• pp.256-261
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• 1997

Effect of a new postemergence herbicide carfentrazone-ethyl on controlling weeds in pear orchards was examined and compared with that of glyphosate and glufosinate. Herbicides tested were applied in mid June when weeds had reached at an average height of 15 to 20cm. The experimented orchards were infested mainly by dicots of Artemisia princeps, Chenopodium album, Polygonum hydropiper, Erigeron canadensis, Commelina cummunis, Calystegia japonica, and Amaranthus ascenders, and monocots of Echinochlor crus-galli, Digitaria sangunalis, Setaria viridis, and several sedges, Carfentrazone-ethyl alone effectively controlled dicot weeds in the orchards, but not monocot weeds. Especially, sedges were not adequately controlled by carfentrazone-ethyl alone at any application rates examined. Glyphosate or glufosinate was more effective to control monocot weeds than carfentrazone-ethyl, whereas carfentrazone-ethyl exhibited higher effect on dicot weeds than glyphosate or glufosinate. Carfentrazone-ethyl mixed with glyphosate of the half recommended rate exhibited a higher degree of weed control, especially of E. crus-galli, as compared to the herbicide mixture of carfentrazone-ethyl with glufosinate of the half recommended rate. However, no phytotocixity of the herbicides to pear trees was observed. Our results demonstrate that catfentrazone-ethyl is useful to reduce the application rates and to accelerate the weed controlling effect of glyphosate or glufosinate. Thus, carfentrazone-ethyl in combination with glyphosate or glufosinate can successfully be used to control the most important weeds in orchards.

• 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.

• Applied Biological Chemistry
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• v.30 no.3
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• pp.227-233
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• 1987

Some derivatives of 3-(benzothiazol-2-yl)-1-methyl urea were synthesized by reaction of methyl isocyanate with 2-aminobenzothiazole derivatives prepared by thiocyanation of various substituted anilines. The compounds synthesized were identified by IR, NMR and mass spectra as 3-(5-methyl benzothiazol-2-yl)-1-methyl urea, 3-(5,6-dimethyl benzothiazol-2-yl)-1-methyl urea, 3-(6-ethyl benzothiazol-2-yl)-1-methyl urea, 3-(6-methoxy benzothiazol-2-yl)-1-methyl urea, 3-(6-chloro benzothiazol-2-yl)-1-methyl urea, and 3-(5, 6-dichloro benzothiazol-2-yl)-1-methyl urea. These compounds were subjected to the test for pre-emergence herbicidal activity in the pots with wettable powder formulation. All of these compounds showed pre-emergence herbicidal activity on the grasses (Digitaria adscendens HENR and Setaria viridis P. BEAUV) and broad-leaf weeds (Portulaca oleraces L. and Chenopodium album L.) at the dosage of 800g a.i. per 10a. Of the 6 compounds, 3-(6-ethyl benzothiazol-2-yl)-1-methyl urea showed the highest herbicidal effect on both the grasses and broad-leaf weeds. Even at the rate of 50g a.i. per 10a, this compound inhibited the growth of grasses, selectively.