• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.4
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• pp.279-282
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• 2002

Oryzalexine A, a potent growth inhibitor against several weeds such as Digitaria sanguinalis (L) Scop., and Amaranthus lividus L. was purified by conventional solvent partitioning and column chromatographies. This substance showed strong inhibitory activity on several weeds: Germination of seeds of Poa annua L. was inhibited by 36.5 % at 1.0 mM and Amaranthus lividus L. by 56.1% at 2.5mM. Growth of root and shoot of Digitaria sanguinalis (L.) Scop. by 10.2% and 22.4% at 2.5mM, respectively. These suggest that Oryzalexine A in rice straw might affect the germination and growth of susceptible weeds and other plants.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.2
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• pp.139-146
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• 1996

An experiment was canied out to investigate how to effect the application of nitrogen, phosphate and potassium on the vegetation and dry matter yield in the mixed sward of Ladino clover and crabgrass(Digitaria sanguinalis [L.] Scop.). The experimental sward was consisted of eight plots of non-application, K, P, PK, N, NK, NP and NPK. These plots were sown with seeds mixture of Ladino clover 5.0kg/ha and crabgrass 17.5kg/ha on 17 April 1976 in the forage experimental field of Kangwon National University, Chunchon, Korea, and were cut three times from 6 July to 4 October 1976.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.2
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• pp.93-100
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• 1995

This experiment was carried out to investigate how to effect the application of nitrogen, phosphate and potassium on the vegetation and dry matter yield in the mixed sward of orchardgrass and crabgrass (Digitaria sanguinalis [L.] Scop.). The experimental sward wa5 consisted of eight plots of non-application, P, K, PK, N. NK, NP and NPK. These plots were sown with seeds mixture of orchardgrass 17.5 kglha and crabgrass 17.5 kg/ ha on 22 April 1975 in the forage experimental field of Kangwon National University, Chunchon, Korea, and were cut four times from 6 July to 18 November 1975. The results obtained were summarized as follows: 1. In orchardgrass density measured after summering, the plot of nitrogen applied without phosphate marked only 3 1.0% of the plot of nitrogen applied with phosphate while in crabgrass density measured at that time the plot of nitrogen applied without phosphate marked as high as 112.5% of the plot of nitrogen applied with phosphate. 2. Application of phosphate and potassium improved wintering record of orchardgrass. In orchardgrass density measured after wintering, the plot of nitrogen applied without phosphate marked only 9.7% of the plot of nitrogen applied with phosphate, and the plot of NP applied without K marked 63.6% of the plot of NP applied with K. 3. In surface coverage of orchardgrass, in midsummer any plot applied with nitrogen regardless of accompanying with or not with phosphate wa5 0%, but in autumn the plot of nitrogen applied with phosphate was 56-58% and the plot of nitrogen applied without phosphate was 5%. While after wintering the plot of nitrogen applied with phosphate was 28-37% though the plot of nitrogen applied without phosphate was only 0.3-0.6%; the application of phosphate improved summering and wintering record of orchardgrass. 4. Application of phosphate demonstrated remarkable effect on increasing dry matter yield in orchardgrass. In year total yield of orchardgrass, the plot of nitrogen applied without phosphate marked as low as 11.3% of the plot of nitrogen applied with phosphate, but in crabgrass the plot of nitrogen applied without phosphate was almost equal to the plot of nitrogen applied with phosphate showing 97.5% of this plot. 5. Application of potassium was not effective on increasing dry matter yield of orchardgrass but its application was effective on increasing dry matter yield of crabgrass. In dry matter yield of orchardgrass significant difference was not found between NP plot and NPK plot, but in dry matter yield of crabgrass NPK plot recorded significantly higher yield compared with NP plot (p<0.05). 6. In botanical composition of the plot of nitrogen applied with phosphate, crabgrass recorded 46.5-50.5% in early summer (July) but in midsummer (August) it dominated the plot recording 85.6-91.2%. 7. In botanical composition based on the year total yield, in the plot of nitrogen applied with phosphate orchardgrass marked 21.7-26.2% and crabgrass recorded 73.8-78.370, but in the plot of nitrogen applied without phosphate orchardgrass marked only 3.5% being overwhelmingly dominated by crabgrass which recorded 96.5%. 8. Application of nitrogen not accompanied with phosphate strengthened competitive power of the crabgrass unilaterally, making orchardgrass be oppressed fatally by the crabgrass.

• Asian Journal of Turfgrass Science
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• v.12 no.4
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• pp.203-210
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• 1998

Environmental concerns arising from synthetic herbicides in plant management systems have led to an interest in plant-derived compounds as natural herbicides. Inhibitory effects of compounds extracted with 50% methanol from corn (Zea mays L.) and pine (Pinus densiflora L.) were evaluated on large crabgrass (Digitaria sanguinalis (L.) Scop.), annual bluegrass Poa annua L.), radish (Raphanus sativus L.), and perennial ryegrass (Lolium perenne L.) The aqueous extracts inhibited seed germination and had postemergence activity on the four species. The stability of biological activity of corn grain, stover, and root extracts was not affected by heating to $135^{\circ}C$ or freezing/thawing treatments when applied at levels above 0.25kg m(sup)-2 based on dry weights of powders before extraction. Heating reduced the activity of pine litter and bark extracts at all levels except the highest application level but had little effect on pine needle extracts.

• Korean Journal of Weed Science
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• v.9 no.1
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• pp.69-75
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• 1989

To search germination inhibitors in higher plants, first of all, some experiments containing selection of test weed seeds and effects of solvents and surfactants for bioassay establishment were conducted. Then MeOH-extracts of 45 plants were assayed for germination inhibition activities against Echinochloa crus-galli (L.) Beauv, Digitaria sanguinalis (L.) Scop., Cyperus iria L., Portulaca oleracea L. and Oenothera lamarckiana Ser. seeds. Among them extracts from Rhathiolepis ovata Briat and Picea abies (L.) Karst showed strong inhibitory effect (60-90% inhibition) on the germination of tested weed seeds at 5000 ppm. On the other hand, the extract from Youngia sonchifolia Max stimulated the germination and growth of tested weeds.

• Korean Journal of Weed Science
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• v.1 no.1
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• pp.78-83
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• 1981

This study was attempted to determine the major weed species occurring in Korean turfgrass, Zoysia japonica Steud. and to evaluate the most effective means for controlling them. More or less 40 weed species were determined to occur in Korean turfgrass. In terms of quantity and frequency of occurrence, Trifolium repens L., Digitaria sanguinalis (L.) Scop., Draba nemorosa var. hebecarpa Lindbl, Erigeron canadensis L., and Cyperus amuricus Max were observed to be the major weeds. Simpson's index, 0.306 was obtained to be the major weeds. Simpson's index, 0.306 was obtained in the golf course, Jinryang, Gyungsan-gun, meaning that no specific weed species were dominant, but in Kyungpook National University campus, Trifolium repense L. was a single dominant species, indicating Simpson's index, 0.776. The most effective herbicides to control Trifolium repense L. and other broad leaf weeds were MCPP [2-(2-methyl-4-chlorophenoxy) propionic acid), followed by 2,4-D (2,4-dichlolophenoxy acetic acid). Increased rates of both herbicides increased markedly their effectivity against weeds, with very slight injury against turfgrass. MCPP at 2.8 kg(a.i.)/ha gave excellent control without any injury and 2,4-D at 1.0 kg(a.i.)/ha.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.82-88
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• 2000

The objective of this study was to determine if wood vinegar of Quercus mongolica Fisch has herbicidal activity. Growth of plants, such as barnyard grass (Echinochloa crus-gulli P. Beauv), quackgrass (Agropyron smithii RYDB), canola (Brassica napus L.), velvetleaf (Abutilon avicennae), indian jointvetch (Aeschynomene indica), and common sorghum (Sorghum bicolor) grown on agar batch treated with 0.01% wood vinegar were similar to that of plant without wood vinegar. The growth of such plants, however, reduced at $0.1{\sim}1%$ concentrations, and inhibited totally at >5% concentration. In greenhouse study, soil-applied wood vinegar did not inhibit tile growth of canola, barnyard grass, large crabgrass, and Abutilon avicennae even at the highest concentration, 80L $80L^{-1}\;10a^{-1}$, while foliar-applied wood vinegar did inhibit the growth of plants at higher than 40L $80L^{-1}\;10a^{-1}$. Growth of canola, barnyard grass, large crabgrass, and Abutilon avicennae treated with wood vinegar (80L $80L^{-1}\;10a^{-1}$) was reduced by 71, 46, 24, and 47%, respectively. In field experiment conducted at Chunchon and Taebeck, biomass of weeds treated with wood vinegar at less than 40L $80L^{-1}\;10a^{-1}$ were close to that of weeds treated without wood vinegar, while biomass of weeds at 80L $80L^{-1}\;10a^{-1}$ was reduced by 34-36%, compared to that of control, at both sites. However, the herbicidal activity of wood vinegar was much lower than that of glyphosate. Results in this study show that wood vinegar of Quercus mongolica Fisch has herbicidal activity, although the herbicidal activity was lower than that of glyphosate, a commercial herbicide.