• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.71-71
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• 2019

The genus Cenchrus (Poaceae), containing ca. 23 species, is distributed throughout Australia, Africa, Indian sub-continent, and America. In Korea, Cenchrus longispinus (Hack.) Fernald, especially introduced to Daecheong Island in 1999, is one of the most hazardous invasive plant which causes serious environmental threats, biodiversity damages and physically negative impact on humans and animals. Based on the next-generation sequencing (NGS) technology, we characterized the chloroplast (cp) genome sequences of C. longispinus which contains a large single copy (LSC; 80,223 bp), a small single copy (SSC; 12,449 bp), separated by a pair of inverted repeats (IRs; 22,236 bp). Additionally, we analyzed the cp genome sequences of Cenchrus echinatus L. which contains a large single copy (LSC; 80,220 bp), a small single copy (SSC; 12,439 bp), separated by a pair of inverted repeats (IRs; 22,236 bp). These cp genomes consist of 75 unique genes, 4 rRNA coding genes, 33 tRNA coding genes and 21 duplicated in the IR regions, of which the gene content and organization are similar to the other Poaceae cp genomes. We selected 40 potential regions in cp genomes of two Cenchrus species and one Korean Pennisetum species to develop new single nucleotide polymorphism (SNP) markers for identifying C. longispinus based on amplification-refractory mutation system (ARMS) technique. The markers, inferred from SNP in matK and ndhF genes, show effectiveness to recognize C. longispinus from C. echinatus and Korean native species Pennisetum alopecuroides (L.) Spreng.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.250-256
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• 2002

The objective was to know if chinese cabbage growers in Gangwon alpine farmland control agricultural pests including weeds effectively and use pesticide properly. Examiners visited 185 farmers at Taebaek, Pyongchang, and Jeongseon and surveyed 33 questions on pest control methods pesticide use. Chinese cabbage farmers have noxious plant diseases such as clubroot, bacterial soft rot, downy mildew, anthracnose, and mosaic disease, and also noxious insects such as diamondback moth, aphid, beet armyworm, common cabbage worm, and Japanese native slug. In addition, farmers have noxious weeds such as common chickweed, marsh pepper, hairy crabgrass, common purslane, and horseweed. To control diseases and insects, 51.3% of farmers used many chemical agents, while 20.7% of farmers used chemical agents with too much emphasis on paraquat and glyphosate to control weeds: 87.2% of the answered farmers have a preference of the both non-selective herbicides. Farmers in the survey area selected pesticides on the basis of their own experience and sales managers' recommendation (84.2%) which results in the use of inappropriate pesticides such diniconazole. Many farmers have experienced phytotoxicities (46.7%) and pesticide poisoning (51.2%). We conclude that a systematic educational program for the proper selection and use of pesticides should be conducted for chinese cabbage growers in Gangwon alpine farmland.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.3
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• pp.336-349
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• 1986

This study was conducted to examine the plant succession on the improved pasture of the mountain districts around Mt. Halla in Cheju Island. For this study, the researcher had investigated for ten years the improved pasture which had been used for grazing from 1976 to 1985. The pasture was reclaimed from native grassland. The mixed seeds of 17kgs' Dactylis glomerata, 7kgs' Festuca arundinacea, 2kgs' Lolium multiflorum and 2kgs' Trifolium repens were sowed per ha. The results of this study are the followings; The annual changes in the number of plant species were observed. 37 weed species were found in 1976 and increased year after year to 151 species in 1985. The changes in the distribution of annual and perennial plant, and one species of arbor were found in 1976 and increased respectively year by year to 56 species (annual plant), 95 species (perennial plant) and 9 species (arbor) in 1985. The average plant height of introduced grasses by year increased from 38.05cm (1976) to 47.30cm (1978) and decreased from 40.50cm (1979) to 10.36cm in 1985 (y =-0.501x$^2$+1.609x + 41.946). While the average plant height of invading weeds increased from 26.61cm to 42.84cm (y=-0.80$\chi$$^2$＋2.540$\chi$＋27.570) between 1976 and 1985. The density of introduced grasses was 70.90% in 1976 and was reduced to 0.49% in 1985 (y =-0.501$\chi$$^2$+1.609$\chi$+41.946); while that of introduing weeds was 29.10% in 1976 and was increased to 99.51% in 1985 (y=-0.080$\chi$$^2$＋2.540$\chi$＋27.570). The coverage of introduced grasses by year increased gradually from 72.8% (1976) to 74.86% (1978) and decreased from 43.01% (1979) to 1.21% in 1986 while that of intruding weeds developed a tendency to increase every year. Their coverage in 1976 was 22.09% and increased to 98.78% in 1985. The weight of introduced grasses by year increased from 2,808kg (1976) to 3,535kg (1978) per l0a and after 1979 decreased gradually from 2,326kg (1978) to 35kg per l0a in 1985. That of intruding weeds increased yearly from 308kg in 1976 to 3,178kg in 1985. The type of annual vegetation were changed as follows; Year Type 1976-1978 Dactylis glomerata / Trifolium repens type 1979 Trifolium repens / Imperata cylindrica type 1980-1982 Imperata cylindrica / Zoysia Japonica type 1983 Imperata cylindrica / Pteridium aquilinum type 1984-1985 Imperata cylindrica / Miscanthus sinensis type The plants whose plant height, coverage, density, and weight increased year after year were Imperate cylind-rica, Zoysia japonica, Pteridium equilinum, Miscanthus sinensis, Cirsium japonicum, Erigeron canadensis, Artemisia japonica, Lespedeza cuneata, Spondiopogon cotuUfer. Cymbopogon tortilis, Plantago asiatica, Rumex acetosella, etc. The vegetation of Digitaria sanguinalis, Hydrocotyl japonica, Artemisia asiatica, etc. was com-paratively remarkable in the beginning.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.1
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• pp.67-76
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• 2010

The purpose of this study was to suggest the growth characteristics, seasonal anthesis distribution and botanical composition of wildflower pasture. The experimental wildflower were 34 species (1 turfgrass species, 4 native wildflower species and 29 introduced wildflower species). The experiment were administered in the Chungnam National University experimental field from March, 2008 to December, 2009 and the result is as follows: the wildflower length were within the range of 8-60 cm and their up-and-down space arrangement quite good. They bloomed into several colors of nine but one or three of nine colors were biased during August, September, and October. Their anthesis was biased toward May and June, and their seasonal distribution and permanence maintenance were too difficult from August and moreover two years later (2009) because of the decrease of the botanical distribution of annual wildflower after winter, the color, seasonal distribution, and permanence of wildflower became a problem. The botanical composition of wildflower, turf grass, and weeds came to 24%, 62%, and 14% each one year later (2008) and two years later (2009) 16%, 69%, and 15% each. Being grounded upon this result, in case of wildflower pasture of spring seeding, it is more important to maintain the color, seasonal distribution, and permanence of wildflower two years later than in the establishment year.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.3
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• pp.227-236
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• 2010

This study was carried out in order to find out the growth characteristics, the seasonal anthesis distribution and the botanical composition of the wildflower pastures which were altogether composed of 90% sheep fescue and 10% wildflowers in the Chungnam National University experimental field from October, 2007 to December, 2009. The experimental species contained 34 species in total consisting of sheep fescue (fundamental turfgrass), 4 native wildflowers, and 29 induced wildflowers belonged. At the time of the anthesis of the wildflowers, the average length was 28.7 cm one year later and 36.7 cm two years later. They bloomed out into from six to nine colors, but into one or three colors during August, September, and October. The blooming season leant toward May and June, and from August, there was lots of difficulty in the wildflower blooming and the maintenance of their consistency. Especially, at the age of two (2009) the color, seasonal distribution, and consistency emerged as problems owing to the reduction of annual wildflowers after winterization. The annual botanical composition of wildflowers, sheep fescue, and weeds came to 22%, 68%, and 10% each one year later (2008) and 19%, 72%, and 9% each two years later (2009). Based on this result, cultivating wildflower in grassland (90% sheep fescue and 10% wildflowers) is the proper method not only for maintaining green space, to prevent soil erosion by sheep fescue, but also for commanding a fine view of wildflowers.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.3
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• pp.217-226
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• 2010

The purpose of this study was to suggest the growth characteristics, seasonal distribution and botanical composition of wildflower pastures. The experimental wildflowers were 34 species (1 turfgrass species, 4 native wildflower species and 29 introduced wildflower species). The experiment was administered in the Chungnam National University experimental field from October, 2007 to December, 2009 and the result is as follows: The length of the wildflowers was within the range of 7-52 cm and they bloomed into six to ten colors but the species of blooming wildflowers and flower colors and blooming periods were simplified during from August to November. Their tendencies were obviously observed two years later (2009) but among them especially the colors, seasonal anthesis distribution and continuation of wildflower became a problem. The botanical composition of wildflowers, turfgrass, and weeds came to 20%, 67%, and 13% each one year later (2008) and two years later (2009) 16%, 72%, and 12% each. Being grounded upon this result, in case of wildflower pastures of autumn seeding, it is more important to maintain the color, seasonal distribution, and permanence of wildflowers occurring due to annual wildflower reduction after wintering in two years, let alone in the establishment year.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.72-83
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• 1997

Forty six natural habitats of Korean lespedeza(Leapedeza stipulacea Maxim.) were investigated for the growth characteristics, mineral contents of plant and the physico-chemical properties of natural habitat's soil compared with the upland soil nearby the habitat. The results obtained were summarized as follows. Plant height and dry matter yield were higher in the samples taken in late than early August showing large variation within the sampling date and location. Korean lespedeza showed higher contents of Fe and Mn, but lower contents of K, Ca, Mg and Cu than Alfalfa. The contents of P and Zn were about the same. The natural habitat showed higher soil pH and Ca content but lower contents of $P_2O_5$, K, and organic matter than the vicinity of natural habitats and the average soil of Korea. The contents of Mg were about the same. The soil texture of natural habitats showed much higher portion of sand and extremely low portions of silt and clay than both area. Korean lespedeza is so well adapted to the soil with low fertilizer and organic matter that other crops and most weeds fail. It also appears to thrive on the sandy loams, loamy sands of the piedmont region such as waste land and on the similar soils with variously physico-chemical properties.

• Weed & Turfgrass Science
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• v.2 no.2
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• pp.138-151
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• 2013

This study was carried out to investigate the distribution and habitat types of prickly lettuce, Lactuca scariola of Europe origin for supplying the basic data of management plan. It showed fairly nation-wide distribution although excessive growth was rather limited in the wild. Its habitat types were divided into four types like open fields, roadsides, seashores and riversides. Species diversity examined by species rank-dominance curve tended to increase over riverside > seashores > open fields > roadsides. As a result of analyzing life form, therophytes were more than 50%, means that the habitats of L. scariola were disturbed by human activities etc. Urbanization Index was analyzed 9.1% in roadsides, 7.4% in seashores, 5.8% in open fields and riversides. It has high spread potential with a large number of wind-flying seed per plant. It was evaluated that prickly lettuce was mainly spread along the newly constructed road, expressway and invaded the original ecosystem in the cultivated land as weeds. But it has played a role as a pioneer species in open fields. It is recommended to remove where it has considerable impact on the native plant species of conservation value.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.3
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• pp.285-294
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• 2011

This study was carried out in the Chungnam National University grassland experimental field from October, 2007 to December, 2009 in order to find out the growth characteristics of the wildflowers, the seasonal anthesis distribution of the wildflowers, and the botanical composition of the wildflowers which were altogether composed of 70% sheep fescue and 30% wildflowers. The experimental species contained 34 species in total to which sheep fescue (fundamental turfgrass), 4 native wildflowers, and 29 introduced wildflowers belonged. At the time of the anthesis of the wildflowers, the average length was 29.9 cm one year later and 38.4 cm two years later. They bloomed out into nine colors, but into one or three colors during August, September, and October. The blooming season leant toward May and June and from August there was lots of difficulty in the wildflower blooming and the maintenance of their consistency. Especially, at the age of two (2009) the color, seasonal distribution, and consistency emerged as problems owing to the reduction of annual wildflowers after winterization. The annual ration of wildflowers, sheep fescue, and weeds came to 25%, 61%, and 14% each one year later (2008) and 22%, 65%, and 13% each two years later (2009). Based on this result, cultivating wildflower grassland in the ratio of 70% (sheep fescue) to 30% (wildflowers) is the proper method not only for maintaining green space by sheep fescue, but also for commanding a fine view of wild flowers.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.271-278
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• 2021

Azolla is a genus of small aquatic ferns native to Asia, Africa, and America. Azolla is potentially significant as a nitrogen source in agriculture, particularly in conjunction with rice (Oryza sativa L.) cultivation. In addition, Azolla may either control weeds or act as a weed depending on management; therefore, we aimed to determine the effect of Azolla incorporation on weed (e.g., Monochoria vaginalis, Rotala indica, Aeschynomene indica, and Cyperus amuricus) control and its other benefits during rice cultivation. The effects of Azolla on weed emergence were evaluated based on plot area coverage by the Azolla mat, which appears as a green sheet over water, and the rate of weed emergence in paddy field. Weed occurrence was investigated 40 days after Azolla inoculation. Soil samples from the experimental plots were collected following harvest in 2014-2015, and analyzed. Moreover, rice growth, yield, and grain quality were measured. Azolla suppressed weed growth by 72%. Azolla mat incorporation in rice fields suppressed weed growth by over 60%. In addition, Azolla promoted nitrogen fixation. Compared with nitrogen management using chemical fertilizers, Azolla incorporation showed the potential for various positive effects, including the improvement of soil fertility by increasing total nitrogen, and organic matter content. Rice grown with Azolla maintained its yield without additional herbicide treatment. Moreover, the palatability of cooked rice was better when grown with Azolla.