• Weed & Turfgrass Science
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• v.7 no.2
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• pp.148-157
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• 2018

Research was initiated to evaluate four domestic and overseas organic soil amendments (SAs) on turfgrass groundcover and density and to provide basic information on practical sports turf establishment. This study was conducted in Agrostis palustris Huds. (CB) grown in sand-based root zone. A total of 20 treatments of SA+sand were prepared by mixing 10 to 50% (v/v). These amendments were SABP (Berger Peat), SAEP (Eco-Peat), SAGS (G1-Soil), and SAPP (Premier Peat). Turfgrass groundcover and density significantly varied with SAs, its mixing rate to sand and week after seeding (WAS). Cumulative turfgrass density was variable, but a great change occurred between 2 and 4 WAS. Turfgrass density at 2 WAS ranged from 36.7 (SABP 30) to 89.7% (SAGS 20), being 53.0% in differences among treatments. However, CB reached to carrying capacity around 6 WAS. Thus, most treatments were similar to 90% or so in density. At the end of study, overall groundcover ranged between 60.7 (SAEP 10) and 96.7% (SAPP 50). Proper mixing rate was variable with SAs, being 10 and 20% for SABP and SAGS, respectively. But the optimum rate was 50% for both SAEP and SAPP.

• Weed & Turfgrass Science
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• v.5 no.1
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• pp.29-34
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• 2016

Large patch disease in Zoysia japonica Steud. is the most destructive disease in turfgrass. For large patch management, it has been dependent on chemical controls but pesticides are harmful to soil, water and biodiversity. In this study, we evaluated 4 Streptomyces spp. strains (S2, S5, S8 and S12) which were selected in previous studies using metagenome approaches. Root colonization of the strains, large patch suppressing effect and the pathogen density change in actual golf course were investigated to evaluate biological control potential of the strains. All strains exhibited reliable root colonization ability that strains populations were higher than $6log\;cfu\;g^{-1}$ in turfgrass rhizosphere. The pathogen density, with S8 treatment, was detected average of 0.7 after a week and average of 1.2 after 4 weeks. Disease control and suppressive the pathogen population by S8 strain showed higher efficiency than other strains. S8 was applied in an actual golf course for the large patch control and pathogen density. The pathogen density in S8 treatment plot was detected below 1.6 per toothpick and lower compared with untreated plot. The results indicated that pathogen density was suppressed by S8 and the stain has great potential as a biological control agent for the large patch.

• Weed & Turfgrass Science
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• v.2 no.2
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• pp.184-190
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• 2013

It is important for genetic resources to collect and identify in native medium-leaf type zoysiagrasses species distributed in Korea. This study was conducted to investigate morphological variation and characteristics of native medium-leaf type zoysiagrasses from coastal, island and inland regions in Korea. Among them, 75 collected lines was confirmed to have various morphological variations, accessions were classified into 2 main based group coastal and inland regions by morphological characteristics and site environment. Group I included Z. sinica type, this group showed 3.7 mm in leaf width, 29 in number of seed per spikelet and 5.0 mm in seed length. Group II included Z. japonica type, this group showed 4.4 mm in leaf width, 42 in number of seed per spikelet and 3.5 mm in seed length. There is a need for additional research on growth characteristics and the molecular level for the introgressive hybridization between species which confirmed that cross-pollination is possible due to protogyny. The individuals showing variations should be preserved as valuable genetic resources for the expansion of variations in zoysiagrasses, and the results of this investigation on the genetic resources collected will be highly valuable in breeding high quality turfgrass.

• Weed & Turfgrass Science
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• v.2 no.1
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• pp.8-14
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• 2013

Collection of weeds were done in 3 remodeled paddy fields located in different districts with different soil moisture conditions such as Samolpo district (14.6%), Gimhae (9.8%) and Chilhyun (5.6%). Remodeled paddy fields composed of 62 plant species belonging to 23 families. Among 23 families, Compositae was the largest family with 11 species belonged to (17.7%) followed by Poaceae with 9 species (14.5%), Leguminosae with 8 species (12.9%), Cyperaceae with 7 species (11.3%), and Polygonaceae with 5 species (8.1%). Summed dominance ratio of each species based on number, coverage, frequency, and plant height in Samolpo district was Echinochloa oryzoides (100%) > Cyperus difformis (9.0%) > Bidens frondosa (5.3%) > Panicum dichotomiflorum (4.8%) > Eclipta prostrata (4.4%). In Gimhae; Digitaria ciliaris (100%) > Panicum dichotomiflorum (49.4%) > Echinochloa oryzoides (48.8%) > Persicaria hydropiper (27.1%) > Chenopodium ficifolium (10.2%), and in Chilhyun were Panicum dichotomiflorum (90.8%) > Digitaria ciliaris (66.7%) > Cyperus iria (8.6%) > Bidens frondosa (7.6%). Total dry weight of weeds recorded was 535.4 g $m^{-2}$, 316.1 g $m^{-2}$ and 346.2 g $m^{-2}$ in Samolpo, Gimhae and Chilhyun districts, respectively. Simpson's index was calculated to 0.09~0.28, which showed that weed occurrence in remodeled paddy fields with different soil moistures varied.

• Korean Journal of Weed Science
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• v.2 no.1
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• pp.47-52
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• 1982

This experiment was conducted to evaluate weed control effect of Butachlor, Oxadiazon, and Bifenox under three levels of water depth (0, 3, 6 cm). Number of E. crusgall. and M. vaginalis decreased as water depth increased while that of P. distinctus showed the opposite trend. Water depth did not influence number of E. kuroguwai and C. serotinus. Weed control effect of Butachlor and Oxadiazon was best at 3 cm water depth at while that of Bifenox was best at 6 cm water depth. Injury of Butachlor to rice decreased as water depth increased while that of Oxadiazon and Bifenox showed opposite trend.

• Korean Journal of Weed Science
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• v.5 no.2
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• pp.143-148
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• 1985

Water hyacinth, unused and tropical plant was examined in order to know the feasibility of application for purification of municipal drainage and industrial wastewater. This plant was effective to remove the COD from wastewater, although its removal ability was dependent on the organic sources. The effects of pH, NaCl concentration, water temperature and shading condition on the growth of water hyacinth were investigated. The optimum ranges of pH were weak acid- neutral, of water temperature were 17-$21^{\circ}C$, and unshading condition was better. The rapid propagation of this plant was also observed during hot summer season.

• Weed & Turfgrass Science
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• v.2 no.4
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• pp.362-367
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• 2013

This study was conducted to develop an efficient control method for water foxtail in the field sowing barley and wheat seeds before rice harvesting. When thifensulfuron-methyl (75%) was applied 0, 5 and 10 days after rice harvesting, little phytotoxicity was observed on both barley and wheat. Percent of water foxtail control with thifensulfuron-methyl (75%) was more than 88% at three different application timing. When butachlor (5%) was applied 5 days before barley and wheat sowing, phytotoxicity on barley and wheat was severe. However, no phytotoxicity was observed on barley and wheat 5 and 10 days after rice harvesting. Percent of water foxtail control with butachlor 0 and 5 days after rice harvesting was 85-89%. However, it dropped to 74-80% when applied 10 days after rice harvesting. In the thifensulfuron-methyl treatment, the dry matter of barley and wheat was 96-108% and 100-108%, respectively when compared with untreated control. While, in the butachlor treatment, the dry matter of barley and wheat was 53-73% and 106%, respectively when compared with untreated control. Therefore, we recommend thifensulfuron-methyl (75%) 0-10 days after rice harvesting or butachlor (5%) 5 days after rice harvesting to provide efficient water foxtail control and safe barley and wheat production.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.4
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• pp.459-469
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• 2009

It is well known that coagulation pretreatment can reduce foulants prior to membrane filtration. The purpose of this research was to investigate the effects of coagulation on fouling of ceramic microfiltration membrane($0.1 {\mu}m$) using pilot plant of $150m^3/day/train$ capacity. Train A membrane system has pretreatment process of ozonation and coagulation while train B has only coagulation. Two types of coagulation operation were investigated: back mixer(rapid mixing with or without slow mixing) which is a conventional mechanically stirred mixer and an inline static mixer. Ozone dose rate for train A was 1 mg/L and ozone contact time was 12 min. The coagulation dose(PACl 10% as $Al_2O_3$) rate was changed 20~40 mg/L according to experimental schedule. In this experimental conditions, the coagulation of back mixer type with rapid mixing(GT=72,000) and slow mixing(GT=45,000) was the best effective in reduction of ceramic membrane fouling regardless preozonation. Especially, the effect of inline static mixer was sensitive to change in water quality. Ozonation mainly affected irreversible fouling rather than reversible fouling in accordance with less adsorption of NOM on the membrane surface. Thus, the increase rate of the nomalized TMP(trans membrane pressure) at $25^{\circ}C$ for train A was relatively lower than that of train B under same coagulation process with same coagulant dosage. The best performance of ceramic membrane appeared in case of combined process with ozonation, therefore this integrated process is able to archive less coagulant dosing and secure a stability of ceramic membrane system.

• Korean Journal of Weed Science
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• v.18 no.1
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• pp.48-53
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• 1998

When rice straw was mulched, the inhibition of weed growth was observed in the barley field. This study was carried to indentify the influence of rice straw extract on germination, shoot and root growth of barley and water foxtail, according to extraction rate, temperature, growth stage, variety and soaking time. The inhibition rate of germination, shoot and root length of barley and water foxtail was higest in rice straw extract of $24^{\circ}C$, 5hours, 10%(w/v). Daerimbyeo's extract among 17 rice varieties inhibited growth of barley most, but Anjoongbyeo's was lowest. Among five growth stages, extract at seedling stages inhibited growth of barly and water foxtail most. Among 10 barley varieties, Seaolbori showed the greatest growth inhibition by rice straw extract.

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.407-412
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• 1997

Allelopathic activity of methanol extract from medicinal plants was determined based on the inhibition of germination, shoot and root length of Echinochloa crus-galli. The response was depended on the source of extracts and concentrations. Of the 20 test plants tested, Cnidium officinale showed most inhibition according to germination, shoot and root length of E. crus-galli. Based on the plant parts, the root extract of C. officinale had more inhibitory effect on E. crus-galli than the stem+leaf extract. Phytotoxic effects of the root extract on E. crus-galli showed 75% inhibition of seed germination, 95% inhibition of shoot growth, and 100% inhibition of root growth at the concentration of 1g/petridish. Sequential partitioning of root extract with organic solvents with increasing polarity showed that the ethylacetate fraction had the greatest inhibitory effect on E. crus-galli. Germination was not inhibited at any rate of ethylacetate fraction but shoot and root growth, were significantly inhibited even at 2mg/petridish. This indicates that the most toxic phytotoxin present in the root extract may be moderate polar compound.