• Korean Journal of Weed Science
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• v.18 no.3
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• pp.214-224
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• 1998

This study was conducted to develop labor and chemical cultural practice improvement for weed control in ginseng field. Five crop species were screened in vitro and three crop extracts were sprayed in the test allelopathic effect for weed species. Methyl alcohol extracts of rice, oat, rye and wheat straw showed inhibitory effect on the germination of six weed species, Amaranthus retroflexus, Chenopodium album, Arthraxon hispidus, Digitaria adscendens, Echinochloa crus-galli, and Setaria viridis. Especially, extract of oat straw was most effective to inhibit the germination of six weed species tested. Also, spraying the extract solution of rice, rye and wheat straw was effective to inhibit the growth of weeds in ginseng field. Ginseng root length, diameter, fresh and dry weight in extract spraying plot were higher than those of non-treatment plot.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.3
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• pp.186-191
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• 1995

This study was conducted to evaluate the effect of herbicides on weed control, growth characteristics and yield in rapes, after direct seeding it to the field. All herbicides treated had no effect on the emergence period, bolting rate of rapes. The major weeds were Cerastium holosteoides var. hallaisanense, Stellaria media Villars, Larnium ampleicaule L., Lobelia chinensis Lour., Geranium wilfordii Maxim. and Capsellu bursa-pastoris (L.) Medicus. Rapes yield were increased somewhat more with alachlor-G, herbicide than the other hehicides and by hand weeding. Alachlor-G and alachlor-Ec were had no i j u r y but butachlor- G and simajin-Wp were slightly harmful for the rapes with recommended concentration. On the other hand all hehicides were harmful in the double dosage level.

• Korean Journal of Weed Science
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• v.31 no.3
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• pp.260-270
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• 2011

This study was carried out to examine the effect of rice bran, barley bran, burned rice bran, and burned barley bran on the growth and yield of Chinese chive (Allium tuberosum Rottler), taro (Colocasia esculenta), and weed control. When the above 4 brans were examined 13, 27, 41 and 57 days respectively after application, the plant height of Chinese chive applied with burned barley bran was significantly higher than non-treated control, whereas the other brans did not have any distinct effect on the plant height or population number of Chinese chive. However, when examined 57 days after the application of the above 4 brans, all the plants applied with brans showed more than twice the improvement in shoot fresh weight compared with non-treated control. A chemical analysis of soil 57 days after the application of the above 4 brans showed that the soils were richer in available phosphate and organic matter. Shoot fresh weight of Chinese chive at 2 weeks after cutting was significantly higher in barely bran treated plot than in non-treated plot. In the case of taro, only taro plots transplanted when 10 cm tall and applied with barley bran showed an improvement in growth increment of both the underground and above parts. However, when sowed seeds after the application of the 4 brans, the yield of taro was reduced by the brans. Thus this research indicates that the effect of brans is differ based on the amount of bran application as well as crops. The effect of weed control on Echinochloa crus-galli, Digitaria clliaris, Chenopodium album, and Solanum nigrum as affected by brans was very low in pot conditions. Weed efficacy of the brans was also very low in field conditions. Growth of Chinese cabbage and garland chrysanthemum was inhibited 63% and 37% by rice bran at $4,000kg\;ha^{-1}$, respectively, but other crops such as maize, squash, cucumber, and Chinese chive were inhibited by 0-20%. These results were similar to that of barley bran except for Chinese cabbage.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.282-290
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• 2010

The objective of this research was to discover the best method for weed management in environment-friendly rice paddy fields through the study on the effect of weed control and injury levels of rice plants as affected by size, input time, and input amount of golden apple snail (GAS). The efficacy of weed control as affected by GAS when applied at 5, 10, and 15 days after transplanting (DAT) was 98, 89, and 58%, respectively. The efficacy of weed control had declined as late the input time of GAS. On the other hand, the efficacy of weed control as affected by rice bran followed by GAS treatment was higher than by GAS treatment alone. Weed species such as Persicaria hydropiper, Echinochloa crus-galli, Scirpus juncoides, and Monochoria vaginalis were not completely controlled by GAS when applied late. Input amount and time of adult GAS (70 days after hatching) for effective weed control were 3 kg $10a^{-1}$ at 5 DAT, 6-7 kg $10a^{-1}$ at 10 DAT, and 7 kg $10a^{-1}$ at 15 DAT. Input time and amount of young GAS (35 days after hatching) for effective weed control were 0 day after harrow (DAH) and 1 kg $10a^{-1}$, respectively. The young GAS when applied 0 DAH at 1 kg $10a^{-1}$ provided 100% control of P. hydropiper, E. crus-galli, S. juncoides, M. vaginalis, Ludwigia prostrata, Eleocharis kuroguwai, Sagittaria trifolia and Cyperus difformis. The rice foliar injury caused by adult (3 kg $10a^{-1}$) and young (1 kg $10a^{-1}$) GAS were 5-7% and 1% respectively. There was no significant difference in rice injury by size and input amount of GAS on plant height and number of tiller. These data indicate that the young GAS when applied 1 kg $10a^{-1}$ at 0 day after harrow was the best method for weed management in environment-friendly rice paddy fields.

• Korean Journal of Weed Science
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• v.4 no.1
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• pp.62-68
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• 1984

This experiment was conducted to find out the possibility for reducing herbicidal dose of the recommended herbicides in combining with the plant growth regulator "chlorflurenol" at the Yeongnam Crop Experiment Station, from 1981 to 1982. Chlorflurenol itself exhibited weed suppression effect against Monochoria raginalis Presl., Rotala indica Koehne, Cyperus difformis L., Lindernia procrembens Philcox, etc. and its effect increased as the concentrations of chlorflurenol increased from 100 to 1,000 ㎖/㏊. Combination of chlorflurenol with butachlor or thiobencarb, showing synergistic effect, reduced their recommended herbicidal rates by 50 to 75%, showing 90% of weed control rate, stic but combined treatment between chlorflurenol and bentazon showed an antagonistic effect since bentazon had poor control ability to Echinochloa crusgalli Beauv. An application of chlorflurenol showed no significant effect on rice growth, in terms of dry weight, but it resulted in the decrease in the ratio of leaf blade to other non-photosynthetic organ.

• Korean Journal of Plant Resources
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• v.10 no.2
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• pp.169-174
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• 1997

This study was conducted to obtain basic information needed to develop the effective weed control method by using thermal weeder which uses LPG as fuel. For survey of weed distribution in herb field, weed species were investigated at two kinds of herb field of Codonopsis lanveolata and Aster scaber located in Hoengseongkun and Hwacheonkun, Kangwondo. In Codonopsis lanveolata field, Digitaria sanguinalis and Persicaria viridis L were dominated. In Aster scaber field, Digitaria sanguinalis and Erigeron canadensis were dominated. In general, Grasses weeds in herb were more dominated than other broadleaf and Cyperaceae weeds. The treatments of $H_2SO_4$ in weed seeds were more effective for germination of several weeds, compared with that nontreated weed seeds. However, the rate of germination differed depending on weed species and tereatment time of $H_2SO_4. Also, viability of weed seeds was significantly affected by irradiation time and temperature. As the temterature and treatment time of irradiation increased, the rate of germination was decreased.

• Korean Journal of Environmental Agriculture
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• v.11 no.2
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• pp.163-169
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• 1992

A cultivar of taro(Colocasia antiquorum var. esculenta Engl.), Tosutoran was cultivated with planting density 60×30 cm at the field of Kwang-ju located in Kyeong-ki province in 1989. The purpose of this experiment was to attain the basic information about the pattern of weed occurrence and the effect of weed control on yield by various treatments in taro field. Ethalfluralin(35 EC), Clomazone(47.1 EC), Paraquat(24.5 Lq.) fb Ethalfluralin and Paraquat fb Clomazone were treated except for untreated plot and hand weeding plot. Weeds occurred were 15 species in 12 families, the dominant weed species were Echinochloa crus-galli, Potulaca oleracea, Acalypha australis in taro field. Weed control effects were higher in combination treatments than in single treatments so the yield was higher in combination treatment than in single treatment. Yield of untreated plot was reduced to 91.8% by comparison with that of hand-weeding plot.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.121-130
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• 1995

Greenhouse and laboratory studies were conducted to investigate allelopathic potential of some weed species on alfalfa(Medicago sativa L.) germination and seedling growth. In the comparison between top(leaves+stems) and root extracts, top extract exhibited greater allelopathic effects on alfalfa germination than that of root. The various weed species extract differently responded to alfalfa test species, WL-320, in terms of allelopathic effect. Top and root aqueous extracts of lambsquarter(Chenopodium album L.), giant foxtail(Setaria faberii Herrm.), redroot pigweed (Amaranthus retroflexus L.), velvetleaf(Abutilon theophrasti Medic.), crabgrass(Digitaria sanguinalis L.), canada thistle(Cirsium arvense L.) and prostrate knotweed(Polygonium aviculare L.) significantly inhibited germination, seedling length, weight, vigor, and rate of germination of alfalfa. The regression slopes of various top extracts showed that velvetleaf(b=3.69) extracts were the most inhibitory, while large crabgrass(b=2.39) extracts had the least allelopathic effect on alfalfa germination. Germination, seedling length and weight of alfalfa were inversely proportional to the concentration of dried velvetleaf extracts. Also, more of the toxic effects were observed from the dried extracts compared to the fresh extracts. Residue of velvetleaf inhibited significantly alfalfa emergence and survival percentage compared to the control. The emergence and survival percentage of alfalfa were 44%, 57% at 1.0% residue treatment, respectively. When weed residues were mixed with silica sand with incubation time, velvetleaf residue most inhibited alfalfa growth. The degree of inhibition increased as incubation time increased. An incubation for 72h caused the greatest inhibition of alfalfa growth. These results demonstrate the different allelopathic activity of weed species extracts on alfalfa and suggest that weed may affect alfalfa growth and development through the inhibitory effects of allelochemicals present in weed tissue.

• Korean journal of applied entomology
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• v.16 no.1 s.30
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• pp.7-12
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• 1977

In order to find out the optimum weeding date for growing barley in paddy field, several kinds of weeding dates and frequencies were made and compared. The results are summarized as follows: 1. As far as the weeding frequencies were fixed with one time, an immediate weeding after wintering resulted better barley grain yield and yield components by causing decreased yield of weed. 2. Maximum allowable date to be free from the weed competition were estimated as not late than February 10 or at most february 25. 3. It is considerable that the effect of weeding was continuously found till March 11 but no significant weeding effect was found when the weeding was done after April. 4. The competition of weed and barley was relatively so higher from February 25 to March 30 that the control during this period seemed to be very effective by causing little decrease in barley grain yield. 5. Major overdominant weeds observed in the paddy field for barley growing period were Alopecurus aequalis S., Stellaria alsine G., and Galium aparin L., in the order of degrees.

• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.1-8
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• 1997

Second year results are presented from a trial designed to quantify the reduction in radiata pine(Pinus radiata D. Don) seedling growth caused by competition from a range of important weed species on a moist North Island site in New Zealand. Radiates pine seedlings(1/0) were grown on the weed free control and with either herbaceous broadleaves, grass, broom, pampas, buddleia, or gorse. Resource(nutrient and water) levels were varied by factorial +/- irrigation and fertilizer treatments. Radiata pine seedling volume growth 21 months after planting was greatest when it was grown on the weed free control or in association with gorse, and was least when grown with either buddleia or pampas. There was no evidence that the effects of the weeds on seedling growth were mediated by either competition for water or nutrients. Tall, fast-growing species that overtopped the seedlings(broom, buddleia, pampas) had the greatest effect on seedling growth and the magnitude of the effect was correlated with degree of overtopping. This implies that shading or competition for light is probably an important factor.