• Asian Journal of Turfgrass Science
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• v.19 no.2
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• pp.131-140
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• 2005

This study was conducted to compare cold tolerances and growth rates of 5 basic species, commercial lines, and breeding lines of zoysiagrass. Total 41 zoysiagrasses were tested at the northern part (Jeokseong-myeon) and the middle part (Cheonan) of South Korea. Cold tolerance (survival rate during winter), growth rate, green-up speed, and density data were collected visually. Four types of zoysiagrasses (Z. matrella, Z. tenuifolia, USm, and S4M2) with genetic characteristics of Z. matrella died during winter cold, while the others survived. Midium leaf type zoysiagrasses, such as Anyang1, Samdeock1, Anyang2, SJ21, and Pyeongdong, with genetic characteristics of both Z. sinica and Z. macrostachya showed vigorous growth rate one year after planting at the northern part (Jeokseong-myeon). Twenty nine ($70.7\%$) zoysiagrasses showed vigorous growth rate, but the other twelve ($29.3\%$) zoysiagrasses died by cold and drought condition at the middle (Cheonan) part of S. Korea. Anyang2, AJ9-7, Samdeock1, Samdeock2, Samdeock3, and Zenith-C showed vigorous growth rate even though cold and drought environmental condition were artificially provided at these region. But, SJ2-19, NSm, 88Mey, 88Mey-7S, 88Mey-9S, SJ2l-10, ASm, and DBm which did not die at the northern part, showed serious injury at the middle part of S. korea. From this results, we can conclude that drought is as important factor as low temperature for zoysiagrasses during winter.

• Journal of Naturopathy
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• v.11 no.2
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• pp.109-115
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• 2022

Background: Studies on the existence and activation of antioxidants in the wild Erigeron canadensis are still incomplete. Purposes: The activity of antioxidant substances was studied by extracting E. canadensis with ethyl alcohol. Methods: After washing the wild turfgrass, extraction with ethyl alcohol was used to investigate the activity of antioxidant substances using various analytical instruments. Results: The highest yield ratio of the extract was 49.3%, and it varied according to temperature and ethyl alcohol ratio. The 50:50 of water to ethyl alcohol at 180℃ was the highest yield. 100% survival rate was in the untreated group and 98-100% in the experimental group at 50 ppm or more of the extract. There was no cytotoxicity at almost all concentrations. The extract of 25 ppm was suppressed by 42% in the test group. The extract of 50 ppm reduced the free fatty acid content by 15%. Cell viability was 20% at the extract concentration of 50 ppm and 24% at 100 ppm. At an extract of 500 ppm, the free oxygen scavenging ability using DPPH and ABTs was 90-98%. When the changes in the free radical scavenging activity of DPPH and ABTs were observed in three dimensions, the antioxidant activity tended to increase at 85℃ as the temperature increased. However, at 85~130℃, it showed a rather decreasing tendency as the temperature increased. Conclusions: There were antioxidants in the ethyl alcohol extract of the wild grass, there was almost no cytotoxicity and suppressed NO production, and the scavenging function of free oxygen was also high. These results provide primary data for the various natural healing uses of the extracts of the turfgrass.

• Korean Journal of Weed Science
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• v.4 no.2
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• pp.149-153
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• 1984

The growth of Calystegia japonica Choisy as affected by pH, drying, burial, soil moisture and light intensity was determined. Germination of C. japonica rhizome was not affected by pH's ranging from 4.8 to 8.7,while the greatest growth after germination was obtained at pH 5.7. Drying longer than 14 h at $35^{\circ}C$ brought about a significant reduction in percent survival and the subsequent growth of C. japonica. A significant decrease in growth of C. japonica occurred when the rhizome was buried at 0 ㎝ and deeper than 8 cm. The greatest growth was obtained when the soil moisture content reached 40 to 60% of saturated soil. Increasing percent available light resulted in decrease in the plant height, but increase in the root length and dry weight.

• 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.

• Asian Journal of Turfgrass Science
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• v.21 no.1
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• pp.9-21
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• 2007

Research was initiated to examine establishment efficiency of zoysiagrass by plugging. Zoysiagrass is known to be a slowly establishing turfgrass species. Properly-treated zoysiagrass seed can speed up the establishment rate, while initial irrigation practice is intensively required after seeding. A planting method with small plugs($2.5{\times}2.5cm$) from seeding can overcome initial watering requirement. Establishment speed, however, can vary with planting dates, planting spaces, and plastic film cover in early stage. Establishment characteristics were investigated for two years by planting dates that were April 5, May 18, July 13, August 24 and October 29 in 2004 and April 6 in 2005. They were also compared with three different spaces($20{\times}20,\;25{\times}25,\;and\;30{\times}30cm$) and three different fertilizer levels(15, 30, and $45g\;N{\cdot}m^{-2}$). Ground coverage reached to 90% in plugs of 'Zenith' zoysiagrass planted on April 5. It increased suddenly in period of July to August, resulting in about 50% of full establishment rate. Establishment rates were significantly faster over 9% in plugs spaced at $20{\times}25cm$ than in those at $30{\times}30cm$. No significant differences were observed on the stolen number and stolen length in the study. Survival rate in zoysiagrass plug was over 90% at all plantings. These results demonstrated that zoysiagrass establishment using small plug from seeding is considered to be a safe and efficient method.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.291-299
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• 2010

Cyhalofop-butyl and penoxsulam, known for respective acetyl CoA carboxylase (ACCase) and acetolactate synthase (ALS) inhibitor, have been widely using as a post-emergence foliar application for many years in wet-seeded rice field in Korea. Since 2009, control of Echinochloa oryzoides with cyhalofop-butyl and penoxsulam was no longer satisfactory. Greenhouse and experiment in rice field were conducted to confirm E. oryzoides resistance to ACCase and ALS inhibitors and to compare herbicide treatments for control of the resistant E. oryzoides to ACCase and ALS inhibitors. Three resistant E. oryzoides to ACCase and ALS inhibitors accessions were tested for levels of resistance to cyhalofop-butyl and penoxsulam, base on survival rate. Iksan and Kimje accessions were not any affected to the survival by treatment with recommended doses of two herbicides tested. Buan accession displayed an intermediate response of 62 and 72% survival at recommended doses of cyhalofop-butyl and penoxsulam, respectively. Survival rates to herbicides mixed with ACCase and ALS inhibitors at 3.5 leaf stage of E. oryzoides was over 80%. Benzobicyclon+fentrazamide+bensulfuron SC, benzobicyclon+mefenacet+bensulfuron SC, benzobicyclone +cafenstrole+pyrazosulfuron-ethyl GR controlled effectively by 2 leaf stage of resistant E. oryzoides to ACCase and ALS inhibitors. In the field experiment, single treatment of benzobicyclon+ fentrazamide+bensulfuron SC and benzobicyclon+mefenacet+bensulfuron SC failed to control E. oryzoides, but squential treatment of benzobicyclon+thiobencarb SE and benzobicyclon+ mefenacet+ bensulfuron SC controlled effectively it in rice infant seedling culture with machine. Our results suggest that resistant E. oryzoides to ACCase and ALS inhibitors had not developed multiple resistance to herbicides with different modes of action. In particular, cafenstrole, fentrazamide, mefenacet were effective control measures.

• Korean Journal of Weed Science
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• v.31 no.2
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• pp.160-166
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• 2011

The purposes of this study were to analyze the weediness potential associated with 'Vitamin A enforced rice' and to evaluate the relationships between growth characteristics and environmental adaption related to survival ability in the natural environment. 'Vitamin A enforced rice', 'Nagdong', donor variety of 'Vitamin A enforced rice' and three other varieties were used for this study. The 'Vitamin A enforced rice' was experimented according to ratio of ripened grain, shattering of grain, germination traits, germination ratio of low temperature, emergence ratio after wintering, ratio of viviparity, and growth ratio after ratooning ability. 'Vitamin A enforced rice' was not significant between 'Nagdong' and other varieties in seven characters. Germination ratio was similar of Vitamin A enforced rice' and 'Nagdong', but average germination ability of was different at low temperature. Also, shattering of grain and germination ratio of alternating temperature were significant between 'Nagdong' and other varieties. These results suggested that the relationships between growth characteristics and environmental adaption in 'Vitamin A enforced rice' could be applied to the stability of weediness potential and biosafety guide in GM rice.

• Korean Journal of Weed Science
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• v.11 no.3
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• pp.205-210
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• 1991

The freezing resistance of Eleocharis kuroguqai was evaluated in artifical and natural freezing conditions in relation to tuber size, depth of tuber burial and soil moisture conditions. Osmotic potential of immature and mature tuber of E. kuroguqai before hardening was -12.1 and -23.5 bar, respectively, but decreased to -61. 0 and -67.1 bar after 120-day hardening period. Percent survival of E. kuroguqai tubers during the winter period was 13% and 67% in dry and moist moisture conditions at burial of 5cm depth, but all tubers were survived in the three moisture conditions employed when buried at 25cm depth. Greater decrease of osmotic potential was observed in tubers buried at 5cm depth than tubers buried at 25cm depth, resulting in greater freezing resistance in the former. Large tuber was more susceptable to freezing temperatures than small tuber.

• Korean Journal of Weed Science
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• v.32 no.2
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• pp.115-120
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• 2012

Weed control is of fundamental importance when planting cereal crops, particularly during the establishment phase. Weeds compete for nutrients, water and light, and can severely threaten the survival and early growth of newly planted crops. Field experiment was conducted to evaluate the effect of ethanol treatment on the weed control efficacy in cereal crops in protected vinylhouse. Five treatments like water, 25 L, 50 L, 75 L, and 100 L per $m^{-2}$ at 2% ethanol were applied and covered with vinyl on 10 days before foxtail millet seeding. After that, foxtail millet seeds were sown on June 20 at $60{\times}10cm$ planting distance and weed control efficacy was recorded at 30, and 50 days after seeding based on the dry weight. Soil oxidation-reduction potential was recorded -200~-400 mV after treatment 2 days. Weed control efficacy of at 75 L, and 100 L per $m^{-2}$ was observed 92%, 84% in 2% ETOH, respectively. Yields of foxtail millet at 75 L, and 100 L per $m^{-2}$ were 1,570 kg $ha^{-1}$, 1,230 kg $ha^{-1}$, respectively.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.57-69
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• 2012

This study was conducted to find the effective management of main weeds including herbicide-resistant Echinochloa oryzicola, Scirpus juncoides and Monochoria vaginalis in direct seeded rice on puddled paddy surface. The dominant dominances in direct seeded rice on puddled paddy surface were increased for three years between 2009-2011. In weed distribution in 2011, the occurrence density of S. juncoides decreased greatly, but it of E. oryzicola increased especially as compared with it of 2009. Benzobicyclon, mesotrione and pyrimisulfan were effective to sulfonylurea(SU)-resistant S. juncoides and M. vaginalis at 5 and 12 days after seeding, however, the efficacy of bromobutide to sulfonylurea-resistant M. vaginalis was decreased slightly at 12 days after seeding. And carfentrazon and pyrazolate were ineffective to S. juncoides. In direct seeded rice on puddled paddy surface which ACCase and ALS inhibitor-resistant E. oryzicola was not occurred, benzobicyclon+penoxsulam+pyrazosulfuron-ethyl ET, bromobutide+imazosulfuron+metamifop GR, and flucetosulfuron+mesotrione+pretilachlor GR showed the control effect over 94% to main weeds included sulfonylurea-resistant S. juncoides and M. vaginalis. The E. oryzicola dominating in direct seeded rice on puddled paddy surface were not any affected to the survival by treatment with recommended doses of cyhalofop-butyl and penoxsulam tested. The ACCase and ALS inhibitor-resistant E. oryzicola was effectively controlled by mefenacet and fentrazamide up to the 2nd leaf stage. In direct seeded rice on puddled paddy surface domiating coincidentally by herbicide-resistant E. oryzicola, S. juncoides and M. vaginalis, "one-shot herbicide" included with mefenacet, fentrazamide, penoxsulam and metamifop could't be used because of low control effect or rice injury. The sequential treatment of benzobicyclon+thiobencarb SE and bensulfuron+mefenacet+thiobencarb GR controlled effectively the herbicide-resistant E. oryzicola, S. juncoides and M. vaginalis in direct seeded rice on puddled paddy surface. The days required by the 3rd leaf stage of herbicide-resistant E. oryzicola, S. juncoides and M. vaginalis in direct seeded rice on puddled paddy surface seeded in May 20 shortened by 4 days as compared with it of June 10.