• Korean Journal of Environmental Agriculture
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• v.25 no.3
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• pp.268-275
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• 2006

ALA (5-aminolevulinic acid) has been proposed as a tetrapyrrole-dependent photodynamic herbicide by the action of the protoporphyrinogen IX oxidase (Protox IX). A study was conducted to determine photodynamic herbicidal effect of ALA on seedling growth of rice (Oryza sativa L.) and barnyard grass (Echinochloa crus-galli Beauv. var. oryzicola Ohwi) under dry and wet conditions. ALA effect on early plant growth of rice and barnyardgrass was greatly concentration dependant, suggesting that it promotes plant growth at very low concentration and inhibits at high concentration. No significant difference in herbicidal activity of biologically and synthetically produced ALAs on plant lengths of test plants was observed ALA exhibited significant photodynamic activity regardless of PSDIP and its duration. Significant shoot growth inhibition by ALA soaking treatment exhibited apparently, indicating that ALA absorbed through root system was translocated into shoot part of plants. ALA reduced plant heights of rice and barnyardgrass seedlings by 6% and 27%, respectively, showing more tolerant to ALA in rice under wet condition. Leaf thickness was reduced markedly by ALA with increasing of ALA concentration, due to mainly membrane destruction and severe loss of turgidity in mesophyll cells, although the epidermal was little affected. It was observed that photodynamic herbicidal activity of ALA applied by pre-and post-emergence application exhibited differently on plant species, and that the activity of ALA against susceptible plants was highly correlated with growing condition.

• Korean Journal of Environmental Agriculture
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• v.16 no.1
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• pp.67-71
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• 1997

This experiment was conducted to test the allelopatic activity on germination and early seedling growth of weed species by barley and sorghum plants residues. The fresh barley extraction inhibited the germination and early seedling growth of weeds, Echinochloa crus-galli, Sataria viridis, and P. oleracea. As the extract concentration increased, the germination and early seedling growth of weeds was significantly inhibited. The water extraction of dried barley and sorghum residues also ehibited the strong inhibition effect on germination and Barley seedling growth of weeds. Digitaria sanguinalis, Siegesbechia pubescens, Sectaria viridis, P. oleracea, E. crus-galli. In the dried barley and sorghum residues mixture into the vermiculite, as the dried residue concentration ncreased, emergence percentage, length of shoot and root of weeds, D. saguinalis, S. viridis, S. pubescens, Ammaranthus lividus, and Solanum nigrum, was significantly inhibited. More than 10% concentration of dired residue caused 80% emergence percentage and growth inhibition. From this study, we conclude that barley and sorghym weeds. These results suggest that barley and sorghum has some possibility to control some weed species like natural herbicide.

• Korean Journal of Weed Science
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• v.31 no.3
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• pp.308-312
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• 2011

A new paddy field herbicide, metazosulfuron granule is an herbicide for controlling annual and perennial weeds occurring in machinery transplanting paddy field. It is recommended to apply $30kg\;ha^{-1}$ 15 days after transplanting. As a result of preliminary tests, it could control seven annual species such as Echinochloa crus-galli, Bidens tripartita, Ludwigia prostrata, Monochoria vaginalis var. plantaginea, etc. and four perennial species including Cyperus serotinus, Sagittaria trifolia, Eleocharis kuroguwai, and Scirpus juncoides. Monochoria vaginalis var. plantaginea, S. trifolia and S. juncoides resistant to sulfonylurea- herbicides were also controlled. Because application timing of the herbicide is wide, it is very efficient to control the spraying timing by users. Phytotoxicity of rice cultivars was not observed, and the impact on the environment is very limited.

• Korean Journal of Weed Science
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• v.14 no.1
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• pp.23-27
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• 1994

Nutrient culture study was initiated to examine the selectivity of dithiopyr(S, S-dimethyl 2-difluoromethyl)-4-(2-methylpropyl)-6-(trifluoro methyl)-3, 5-pyridine dicarbothiate) in rice(Oryza sativa L.) and barnyardgrass(Echinochloa crusgalli Beauv.). Absorption and translocation of $^{14}C$-dithiopyr in rice and barnyardgrass were also investigated to determine their selective mechanism. Rice was very tolerant, but barnyardgrass was susceptible to dithiopyr. The absorption of dithiopyr was greater in barnyardgrass than in rice and most of them remained in the roots of both species. Dithiopyr was absorbed by roots and basal shoots of both species. Translocation of dithiopyr was very low but was higher in barnyardgrass than in rice. Therefore, this study suggest that the selectivity of dithiopyr between rice and barnyardgrass may be mainly attributed to the absorption and translocation of dithiopyr in plants.

• The Korean Journal of Ecology
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• v.3 no.1_2
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• pp.1-10
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• 1980

This study was carried out to find out the correlation between plant groups and environomental gradient in the native grassfild near Kang Nam Express Terminal from August 26 to september 15, 1977. The correlations among plant species were calculated by using the method of x2 and the various relationships among soil environmental gradients were grouped by means of correlation coefficient. As a result, both the species and the soil environmental factors could be subdivided into four groups, and the four groups of the native grassfield were turned out to be correlated with the four groups of soil environmental factors. The first plant group (Panicum dichotomiflorum, Chenopodium album, Bidens forndosa, Humulus japonicus, Alopeculus amurensis, Potentilla fragarioides, Centipeda minima, Beckmannia erucaeformis) was formed in the releve 1∼10 reagions, organic matter by Turins's method, Total N, Exchange Ca and total of Exchange K, Na, Kg, Ca were abundent. The second plant group (Digitaria sanguinalis, Paltulaca oleracea, Echinochlea macrocrovi, Cyperus amuricus) was formed in the relve 11∼18 reagions, where Exchange Ca and total of Exchange K, Ng, Mg, Ca were little but Exchange A1 and sand were aburdent. In relve 19∼20 reagions, with much of Exchange Ca, total of Exchange K, Na, Mg, Ca, pH and a little Exchange Al, was found the third plant group (Pycreus sanguinoloentus, Cyperus amuricus, Ludwigia prostrata, Echinochloa echinata, Polygonum thunbergii, Salix glandulosa seedling) The fourth plant group (Cassia nomame, Polygnoum perfoliatum, Setaria viridis, Glocien ussuriensis, Lactuca indica, setaria glauca, Artemisia capill aris, Artmisia asiatica, Calamagrostis arundinacea, Kummerowia striata, Denothera odorata, Artemisia japonica, Carey laceolata) was formed in relve 21∼25 reagions, where organic matter by loss on ignition, Exchange Mg and Maximum water holding capacity were abundent but sand was a little. Thus it can be concluded that there is a close relationship between the vegetation group clasified by meaus of x2 and the environtal factors of soil devided by means of correlations coefficient.

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

• Journal of Bio-Environment Control
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• v.15 no.3
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• pp.277-282
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• 2006

For searching the natural herbicide-components, the seed germination and seedling growth of receptor plant species (Brassica campestris, Sesamum indicum, Perilla frutescens and Echinochloa crus-galli) were investigated in four solvent-extracts extracted from Coptis chinensis Franch. The seed germination of receptor plant species was largely inhibited in 2,000 ppm of ethyl acetate compared to the control, and it was inhibited in order of P. frutescens, B. campestris, E. crux-galli, and S. indicum. In seedling growth, the shoot and root elongations of receptor plant species were inhibited in order of S. indicum, P. frutescens, B. campostris, and E. crus-galli. Root elongation was remarkably reduced in order of $H_2O$, butyl alcohol, and hexane, ethyl acetate extracts. Of four receptor plant species, seed germination and seedling growth of B. campestris and S. indicum showed the species-specific reaction to the solvent-extracts extracted from C. chinemis. $H_2O$ extract had a natural herbicide potential to the seed germination or root elongation in B. campestris and S. indicum. The result can be provided a basic data f3r the development of natural herbicide.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.312-317
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• 2014

This study was conducted to obtain basis information for effective weed control by the fact-finding survey of herbicides use at farmer's level and distribution of herbicide resistant weeds in paddy field of Jeonbuk province, Korea. The distributions of major paddy field weeds and frequently used herbicide according to the survey were as follows. The dominant weeds in rice paddy field were Echinochloa crus-galli, Eleocharis kuroguwai, Scirpus juncoides, Monochoria vaginalis, etc.. Preferred herbicides widely used by farmers were ranked in the following order, early and middle treatment (48.0%), treatment before transplanting (36.7%) and foliar treatment (15.3%). The occurrence of herbicide-resistant weeds according to collected paddy soils was as follows. The occurring area of herbicide-resistant weeds was 24,413 ha, approximately 18.4% of rice cultivation area. Herbicide-resistant weeds were occurred in four species. The order of occurrence were Scirpus juncoides (39.0%) > Monochoria vaginalis (27.8%) > Echinochloa crus-galli (16.6%) and Cyperus difformis (16.6%). This information could be useful for estimation of future herbicide-resistant weed and establishment of herbicide-resistant weed control methods in Jeonbuk province, Korea.

• The Korean Journal of Ecology
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• v.24 no.5
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• pp.309-313
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• 2001

This research was conducted to test cadmium tolerance by five speices of native herbs for screening cadmium tolerance plant. We examined germination rate, root and shoot growth rate of seedling, fresh biomass of native herbs exposed to cadmium solution for 14 days. Especially, germination rate of Abutilon avicennae and Amaranthus retroflexus was over 90% in all concentration, but germination rate of Aeschynomene indica, Echinochloa crus-galli var. oryzicola and Echinochla crus-galli var. frumentacea began to decrease when they exposed to 15 mgCdSO₄ /L. The higher the Cd concentration, the length of root, shoot grew lower. The fresh biomass of Echinochloa crus-galli var. oryzicola, Echinochla crus-galli var. frumentacea and Amaranthus retro-flexus were not so different from each control, but those of Abutilon avicennae and Aeschynomene indica began to decrese greatly when exposed to 60 mgCdSO₄ /L. EC/sub 50/(Effective Concentration 50%) of Abutilon avicennae, Aeschynomene indica and Amaranthus retroflexus was 44.6∼77.5 mgCdSO₄ /L for root growth, 38.6∼114 mgCdSO₄ /L for shoot growth, 60∼107.5 mgCdSO₄ /L for fresh biomass. Among the native herbs, sensitivity of cadmium ordered as root length > fresh biomass > shoot length. These results indicate that Abutilon avicennae is a tolerant species for cadmium.

• 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.