• Korean Journal of Weed Science
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• v.8 no.3
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• pp.265-272
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• 1988

This experiment was carried to investigate the germination pattern in relation to temperatures and lights, and the emergence pattern in relation to seeding depths, lights and the alpha amylase activity of Youngia sonchifolia, Lactuca indica var. laciniata, Ixeris dentata var. albiflora and Ixeris polycephala. In Y. sonchifolia, the optimum germination temperature was $25^{\circ}C$, the optimum seeding depth to emerge was 0 mm and it could emerge in 0-5mm. In L. indica var. laciniata under cool storage, the optimum germination temperatures were $19^{\circ}C-28^{\circ}C$, the optimum seeding depth was 5mm and it could emerge in 0-20mm. In L. indica var. laciniata under room storage, the optimum germination temperature was $25^{\circ}C$ the optimum seeding depth was 5mm and it could emerge in 0-10mm. In I. dentata emerge was and 0mm and it could emerge in 0-5mm. In I. polycephla, the optimum temperatures were $16^{\circ}C-19^{\circ}C$, the optimum seeding depth to emerge was 0mm and it could emerge in 0-5mm. The alpha amylase activity was lower Y. sonchifolia, L. indica var. laciniata and I. dentata var. abiflora than barley cultivar Dongbor#1. And the increased pattern of alpha amylase activity was likely to it of germination rate.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.215-224
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• 2010

A greenhouse experiment was conducted to determine the effects of medium components and shade treatment on the growth, contents of total phenolics and flavonoids, and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity of Youngia sonchifolia. Substrates combined with coco peat and perlite (ratio 70:30 or 50:50, v/v) showed higher plant length, leaf area, and fresh weight than single substrate (P<0.05). Shade treatment also significantly reduced plant height, root length, leaf areas, and fresh weight (P<0.05) with increasing of the degree. Shading treatment, however, increased contents of total phenolics [mg ferulic acid equivalents $kg^{-1}$ dry wt.] and total flavonoids [mg naringin equivalents $kg^{-1}$ dry wt.] in shoot parts of Y. sonchifoli, showing 110.2 to 119.2 and 128.3 to 146.7 mg $kg^{-1}$, respectively. The antioxidant potential of the methanol extracts from the plants dose-dependently increased DPPH free radical scavenging activity, and the activity was higher in shoots (50.2 to 80.8%) than in roots (47.7 to 49.8%), and in shading treatment than in no shade.

• Korean Journal of Weed Science
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• v.7 no.2
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• pp.236-242
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• 1987

The study was conducted to interprete the fluctuation of weed vegetation in plant-sociological impacts as affected by the mixture use of oxyfluorfen and glyphosate with various dosages. Also, intended to know the real interaction between two herbicides in weeding efficacies. The better efficacy from the above mixture was recognized than from the oxyfluorfen + paraquat mixture on the perennial-sites. In lower rate mixture of oxyfluorfen, the dominance index was increased by the annual grass species (ie. Digitaria), and of glyphosate by the biennial Stellaria and perennial species (ie. Artemisia). Also, the positive maximum action of both oxyfluorfen and glyphosate in various mixture rates was categorized upto 0.55kg ai/ha for oxyfluorfen and 0.35kg ai/ha for glyphosate, respectively. However, the interaction between the above two herbicides recognized actually as negative. Consequently, the use of mixture compound of oxyfluorfen with glyphosate are expected rather to promote the control efficacy of specific weed species, to enlarge the weeding spectrum and to prolong the weeding periods than to reduce the application rate of both chemicals depending on any synergic interactions.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.241-246
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• 2016

This study was conducted to examine the effects of Glycine soja (GS) supplementation on the quality of corn silage. Corn silage was used in a $3{\times}2$ factorial arrangements with respective factors being addition of GS (0, 10, and 20%) and without or with Lacobacillus plantarum as lactic acid bacteria, and were stored for 40 days at a room temperature ($20-25^{\circ}C$). Corn silage with supplemented 20% GS increased (p<0.05) crude protein contents compared with that in corn silage with supplemented 0 and 10% GS, however crude fat, NDF, and starch concentrations was not affected (p<0.05) by addition of GS. Furthermore, the interaction was found (p<0.05) between corn silage with supplemented 20% GS and the addition of lactic acid in butyric acid. Silage pH was increased while GS supplementation increased. Corn silage with supplemented 20% GS increased (p<0.05) glucose and fructose concentrations. The results of current study indicate that corn silage with supplemented 20% GS could be used as a useful strategy to improve corn silage with increased crude protein contents along with sucrose, glucose and fructose concentrations.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.224-228
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• 1991

This study was carried to know factors affecting emergence of major upland weeds in soil in order to get basic information on weed control methods. Firthy eight percent of weed seeds were distributed within soil surface to 10cm in soil and 2% of weed seeds were observed in 40~50cm soil layer in field. As planting depth was deeper, emergence of weeds became poor. However Capsella bursa-pastoris can emerge at soil surface. Amaranthus retroflexus, Amaranthus lividus, Porturaca oleracea, Chenopodium album, Solanum nigrum upto 3cm, Eleusine indica, Echinochloa crus-galli, Setaria viridis, Digitaria sanguinalis upto 7cm. Emergence of weeds was very poor in very acid soil but good in soil pH 5.5~6.0. However emergence of weed was not affected by pH 3.5~4.0 or above. Emergence of E. indica, C. bursa-pastoris, A. retroflexus, A. lividus, C. album, E. crus-galli, Solanum nigrum, and S. viridis was good in loam soil and P. oleranea, D. sanguinalis in sandy loam soil. Emergence of weed seeds was not affected by fertilization.

• Korean Journal of Weed Science
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• v.10 no.3
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• pp.202-206
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• 1990

Field experiment was conducted to develop a model of controlled release of oxyfluorfen by using various split applications. Rice and some weed species was included in this study. The models of split applications were 10-10-0. 10-10-10. 20-20-0, 20-10-10. 20-20-20, 0-40-0, and 0-0-0g/Ha at 3days before transplanting, and 11 days after transplanting, respectively. Rice injury appeared dispeared at 20 g/Ha of oxyfluorfen on low leaf sheath but disappeared at few days. The injury was reduced by split application even at the same rate of application. However, no injury was siginificant at 30 days after transplanting. Barnyardgrass, Monochoria, and arrowhead were most susceptible to oxyfluorfen, but bulruch and most perennial weeds recovered after temporary growth inhibition. Therefore, to develop oxyflourfen for use in rice transplanting of adult rice seedling, split application with reduced rates, and development of expected to be tank-mixed or premixed with other perennial herbicides to obtain droad spectrum of weeds.

• Korean Journal of Weed Science
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• v.18 no.4
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• pp.304-313
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• 1998

Foliar retention of pyribenzoxim (1% EC) was measured using the fluorescent dye rhodamine B, and related to efficacy and phytotoxicity to barnyardgarss (Echinochloa crusgalli) and rice (Oryza sativa cv. Chucheong), respectively. Effects of nozzle types (8002E flat-fan and disk-type), addition of adjuvant, variation of herbicide concentration or spray volume were compared. In barnyardgrass, foliar retention of pyribenzoxim at a recommended condition (application rate : 30g ai/ha, spray volume : 1000 L/ha) was 2.3 to 2.7 or 1.4 to $1.5{\mu}g$ ai/g fresh foliage when sprayed using the disk-type nozzle with or without adjuvant, respectively, and 0.6 to 0.7 or 0.3 to $0.5{\mu}g$ ai/g fresh foliage when sprayed using the flat-fan nozzle with or without adjuvant, respectively. The slope of increase in foliar retention was 1.0 to 1.8 when application rates increased from 10 to 60g ai/ha at 1000 L/ha, while that was 1.6 to 2.4 when spray volume increased from 330 to 2000 L/ha at $30{\mu}g$ ai/L concentration. Foliar retention of pyribenzoxim had a close relationship with herbicidal activity; regardless of spray conditions, retention to provide 90% control was about $0.8{\mu}g$ ai/g fresh foliage, and below this retention amount, efficacy decreased almost linearly. In rice, foliar retention at the recommended condition was 1.9 to 2.3 or 1.2 to $1.3{\mu}g$ ai/g fresh foliage when sprayed using the disk-type nozzle with or without adjuvant, respectively, and 0.6 to 0.9 or $0.3{\mu}g$ ai/g fresh foliage when sprayed using the flat-fan nozzle with or without adjuvant, respectively. The slope of increase in foliar retention was 1.0 to 2.8 when application rates increased from 30 to 120g ai/ha at 1000 L/ha, while that was 1.3 to 4.4 when spray volume increased from 1000 to 4000 L/ha at $30{\mu}g$ ai/L concentration. Despite the great difference in retention, rice phytotoxicity was not observed in any of these spray conditions, suggesting retention differences within 4-fold increase of application rate or spray volume do not affect rice safety. When pyribenzoxim 1EC was sprayed in tank-mix with several other commercial pesticide formulations, its retention to rice foliage tended to increase by 30 to 50%.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.188-194
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• 2012

Field experiments were conducted to investigate the competition relationships of main paddy weeds with transplanted rice grown in paddy conditions. Data were used to predict crop yield as a function of weed density using a rectangular hyperbola model and determine weed economic threshold (ET) levels. The rectangular hyperbola (equation 2) was fitted to rice yield to estimate weed-free rice yield ($Y_o$) and weed competitivity (${\beta}$). Its competitivity for M. vaginalis was 0.0007445, 0.0005713, 0.000988 and 0.0008846 in Daejeon, Suwon, Iksan and Naju, respectively. The competitivity at harvest represented by parameter ${\beta}$ ranged from 0.001611 in Naju to 0.002437 in Iksan for S. trifolia. The ET levels of main paddy weeds in machine transplanted rice cultivation were well estimated based on the herbicides applied and its application cost. Therefore, our results can be used to support decision-making on herbicide application for weed management in transplanted rice cultivation.

• Korean Journal of Weed Science
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• v.4 no.2
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• pp.194-203
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• 1984

To evaluate the compatibility in systemic use of 4 kinds of herbicides on both weeds and soybeans, trials were conducted at Coll. Exp. Farm/Jonnam Nat'l. Univ., 1983. Among the experimented 4 herbicides, alachlor or metribuzin were applied at pre-emergence, and followed by postemergence spraying of acifluorfen or bentazon, respectively. All herbicides were applicated at rates of 0, 0.25, 0.5, and 0.75 kg active ingredients per ha. Under the conditions which Echinochloa crusgalli and Digitaria adscendense were dominating, most comprehensive compatibility was found from each rates 0.5 - 0.75 kg/ha at 60 days after crop seeding date. However, slight transient leaf burn was evident at the plots of metribuzin and/or acifluorfen applicated. The positive tendency of herbicide interactions in weeding efficacy was observed from the system in alachlor sequence. However, the results in crop growth and yields at hervest indicate the necessity of higher rates of each herbicides upto 0.75 kg/ha for the consistence weeding efficacies. And more excellent weeding results (crop growth and yields) on crop plants were provided from the plots which applicated by residual type herbicide, namely acifluorfen than bentzaon.

• Korean Journal of Weed Science
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• v.18 no.1
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• pp.63-68
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• 1998

This experiment was carried out to select some herbicides for edible wild greens, Album monanthum, Petasites japonicus, and Aster scaber. The herbicides tested were napropamide 21.8% EC, nitralin 50% WP, and pendimethalin 31.7% EC. Dorminant weeds in the field were Echinochloa crus-galli, Digitaria sanguinalis, Persicaria hydropiper, Chenopodium album, and Siegesbeckia pubescens. Simpson's index was calculated to 0.26~0.30, which showed that weed occurrence in the field was quite various. Control efficacy in the field treated with napropamide EC 872g(ai/ha)., nitralin WP 1,000g(ai/ha), and pendimethalin EC 634g(ai/ha) were 81.4%~85.6%, 79.4%~82.8%, and 86.8%~92.2%, respectively. The typical phytotoxic symptoms to herbicides were germination inhibition, growth retardation, and malformation.