• Korean Journal of Food Science and Technology
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• v.14 no.2
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• pp.156-161
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• 1982

Three plastic film solar dryers covered with different film layer were constructed by modifying farm vinyl house and studied their performance. The collection efficiency and temperature raising of type C which was covered with double layers of transparent PE and black PVC film was most efficient, followed after B covered with double layer of transparent PE film and type A covered with single layer transparent PE film. The inside temperature of type C was average $18^{\circ}C$ higher than ambient temperature and its collection efficiency showed 31.5% with air flow rate of $3.8m^3/min$. The solar energy collection efficiency of type C was increased in proportion to air flow rate up to 60.2% at $11.3m^3/min$. In demonstration drying test of red pepper in type C, drying capacity per unit area was 2.5 times higher than that of conventional solar drying on straw mat and drying time shortened to about half.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1996.05a
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• pp.91-115
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• 1996

In the recent years, protected horticultural facilities have been modernized and glasshouses are also propagating in Korea, even most vegetables production are conducted in the traditional plastic houses covered with, for example, PVC film for just temperature keeping. It would limit the productivity and competitivity of the vegetable production industry without automatization and high quality year round production. A plant factory, aimed to produce vegetables in the limited areas, was initiated in Christensen farm, Denmark in 1957, and widely propagated in some developed countries. As it has the automatized system which enables to keep optimized environment conditions, it will be the best facility for high quality products as well as year round planned production. However, we have not even started the plant factory production. Since the plant factory is requiring lots of resources, besides plant cultivation technologies, such as environment control, automatic engineering and robotics, our approach to the development of plant factories should be minded on Practical Plant Factories considering our current farming practices and least capital needs rather than blindly employing the advanced technologies from developed countries. Thus, Korean plant factory development can be initiated with year round leaf vegetables production in NFT or DFT cultivation system instead of the moval bed system, in which aerial environment factors such as light, temperature, humidity and CO$_2$ concentration and root environment ones such as solution concentration, temperature, pH and water soluble oxygen shall be automatically controlled. And the seeding, seedling and transplanting operations shall be accomplished in the house entrance, and the harvesting and grading opreations shall be conducted in the house exit. For practical plant factories, environment control technologies including artificial light source, illumination and air conditioning, automatic management for nutrient solution and automatic production line of moval bed system, transplanting and harvest should be developed along with researches on the cost reduction of factory building construction.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.380-390
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• 2005

This study was carried out for looking into the status of susceptibility of vinyl house insect pests to insecticides. The Thrips (Thrips palmi and Frankliniela occidentalis), Mites (Tetranychus urticae), Aphids (Aphis gossypii) and Whitefly (Trialeurodes vaporariorum) were captured at various areas where the host crop was being cultivated and the susceptibility level of each pest insect was investigated. The susceptibility of each pest insect varied by insect species and areas where they were caught. The tested insecticides showed good control effect to palm thrips in 2000, but in 2003 showed decrease of effect to them. Western flower thrips showed low susceptibility to neonicotinoids, imidacloprid and thiamethoxam, but high to chlorfenapyr, spinosad, emamectinbenzoate and fipronil. Antibiotic insecticides, abamectin and milbemectin, and chlorfenapyr were very effective on mite control and dicofol still had good effectiveness to it despite of long year use. No aphid species showed resistance to pyrethroid and carbamate insecticides. Relatively new insecticides such as imidacloprid, spinosad, pymetrozine were effective to whitefly, but not were organophosphates, carbamates and pyrethroids.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.4
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• pp.315-323
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• 2005

For reconstruction of the bony defect, distraction osteogenesis has many advantages in comparison with bone graft. However, it needs long consolidation period for sufficient bone maturity. This study is performed to evaluate the effect of PRP injection into the distracted mandible on bone formation in rabbits. Twelve house rabbits, weighing 2 kg, were used. All animals underwent bilateral mandibular osteotomy under general anesthesia. A internal distractor divice was positioned along a plane perpendicular to the line of osteotomy. After 5 days of latency period, distraction osteogenesis was started at a rate of 1 mm/day for 9 days which was distracted 9 mm totally. After completion of distraction, 0.5 ml of PRP which collected in rabbit blood was injected into the distracted mandible on experimental group, whereas no injection was done in control group. Macroscopical, radiographical, and histological, and histomorphometric examinations were performed 2, 4 and 8 weeks after distraction. All animals showed distracted mandible and severe anterior cross-bite. In radiographical findings 2 weeks after distraction, more radiopacity in the distracted gap was found in experimental group than that of control group. At 4 weeks after distraction, distracted bone was similar to normal bone in experimental group. In histological findings, 1) At 2 weeks after distraction, number of osteoblasts and angiogenesis in the distracted gap was found in experimental group than that of control group. 2) At 4 weeks after distraction, more active and distinct bone in the distracted gap was found in experimental group than that of control groups. 3) At 8 weeks after distraction, more dense and matured lamellated bone in the distracted gap was found in experimental group than that of control group. In histomorphometrical findings 8 weeks after distraction, more bone formation was observed in experimental group than control group (p<0.01). These results indicate that administration of PRP into the distracted mandible can promote bone formation.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1164-1172
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• 2012

This study aims to make a "farmland use map" using high-resolution images and to analyze the land use change for about 8 years in Goyang, Namyangju, and Yongin cities. We have made a new numerical map named as a farmland use map using high-resolution images taken mostly in 2007 and digital topographical maps in Goyang, Namyangju, and Yongin cities near metropolitan areas to classify farmland use of paddy, upland, plastic film house, and orchard. We also made a land use map by overlaying the farmland use map and the land registration map of each city made in 2007, and compared the land use map made by RDA (Rural Development Administration) in 1999. Paddy areas decreased at a range of 3,000 to 5,000 ha during 8 years and were changed to residential areas in the cities. Upland and orchard areas also showed similar tendency and were changed to residential areas as well. On the other hand, the areas of the plastic film houses in the cities showed an increase or same in size. It is suggested that farmland use map can be broadly used as a base map for various survey projects including soil survey, statistics, and farmland information management.

• Asian Journal of Turfgrass Science
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• v.26 no.1
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• pp.1-7
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• 2012

Field experiments were conducted to evaluate the morphological characteristics and growth rates of 101 medium-leaf type zoysiagrasses (Zoysia spp.) collected at the major sod production area (Jang Seong Gun) in South Korea. Collected lines with distinctive morphology and visual growth rate were planted in plastic pots and measured morphological characteristics under the plastic house conditions. Variation of leaf width, plant height, leaf angle, length of leaf sheath, trichome, stolon length, and color were measured. Six lines were selected by evaluating growth rates from one hundred one collected lines. Eight standard cultivars and three other superior lines previously collected were compared to 7 selected lines form Jang seong area by checking growth rates and morphological characteristics. Average leaf blade width was 3.4 mm, leaf angle was 45.8 degree, plant height was 21.6 cm, height of lowest leaf was 5.0 cm, and length of leaf blade was 14.1 cm. Ground cover rates of selected lines 'CY6097' and 'CY6069' were 70% and 68.3%, respectively. These are believed to be faster than 60% ground cover rate of zoysiagrass 'Anyang', and also, twice as faster than the 31.7% ground cover rate of Z. matrella. Selected line 'CY6069' showed fast growth rate with shorter internode length (5.1 cm) compared to zoysiagrass 'Anyang'. Based on the results of this study, we could select useful fast growing zoysiagrass breeding lines from the major sod production area (Jang Seong Gun) in Korea.

• Research in Plant Disease
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• v.23 no.2
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• pp.186-192
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• 2017

To survey the incidence of plant-parasitic nematode in strawberry nursery, 117 soil samples were collected from main producing area of strawberry nursery plants in 2016. The incidences of two major problematic nematodes such as root-lesion nematodes (Pratylenchus spp.) and root-knot nematodes (Meloidogyne spp.) were 11% and 3%, respectively. Strawberry nurseries using upland soil either in fields or in plastic-houses showed were higher infection rates of Pratylenchus spp. or Meloidogyne spp. than others. On the other hand, a strawberry nursery using pots filled with bed soil in plastic-house was the lowest infection rate with 0%. Phylogenetic relationships and distance analysis were performed for identification of Pratylenchus spp. and Meloidogyne spp. detected from strawberry nurseries. As the results, they were identified as Pratylenchus penetrans, Pratylenchus vulnus and Meloidogyne hapla. Meanwhile, when nursery plants of strawberry infested with P. vulnus transplanted to pots filled with sterilized soil, P. vulnus was detected from soil in pots as 33% frequency. Thus, P. vulnus can be spread through nursery plants of strawberry infested with that. These studies suggested that Pratylenchus spp. and Meloidogyne spp. were ploblematic nematodes in major areas of strawberry nursery plants and P. vulnus could be spread through nursery plants of strawberry.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.65-69
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• 1998

In order to evaluate the utility of bituminous coal fly ash, gypsum, oyster shell as soil amendments, aadic clayloam paddy soils with low calaum content were amended in the upper 15㎝ with amendments, and then Chinese cabbage was cultivated under plastic film house. Amendments treated were, in metric tons per hectare, i) none(Check) ; ii) 80 fly ash(FA) ; iii) 4 shell(SH) ; iv) 56 fly ash+24 gypsum (FG) ; v) 40 fly ash+24 gypsum+0.8 shell(FGS). On the whole, soil chemical properties were improved by amendments treatments. Amongst treatments, FA prominently neutralized soil pH and increased contents of Av. $P_2O_5$, Ex. K, and Av. B in soils. Besides, it showed the highest ratio in bacteria/fungi and (bacteria+actinomycetes)/fungi. FGS also affected the neutralization of soil pH and the increment of Ex. Mg. Amendments plants appeared alkaline damages only at early growing stage, but showed positive responses in fresh weight yields : 23% for FGS : 21% for FG : 19 18% for SH. At harvesting, leaves both of FA and FGS plants had higher values in contents of N, P, K, Ca, Mg, Fe, Mn, Zn, B, reduang-sugar, and vitamin-C than of others. In especial, Check plants appeared the heart rot symptoms owing to calaum defiaency differently from amendments plants. Taken together, FGS was an effective combination enable to maximize the utility of fly ash, gypsum, shell as soil amendments, espeaally in cabbage yield and quality.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.600-607
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• 1995

Orostachys japonicus, called Wasong and used as anti-tumor medicinal plant, was cultivated in plastic house. The experiment was done to clarify the effect of long-day and night-break treatment at the timing of bolting on its morphological characters, organ dry weight and flowering of florets. After grown in 15cm plastic boxes containing 2:1 soil:peat moss mixture for about 4 months, long-day of 16 hours and night-break of 2 hours around midnight were treated from Sept. 9. The plants were sampled 5 times at 2-week interval after the treatments. Long-day and night-break treatment delayed the growth of inflorescence and showed greater stem diameter on the last sampling and no. of leaves and bracts than the natural daylength. The treatments also had greater leaf and bract dry weight since 2 weeks, and the other fraction and total dry weights since 4 weeks but less floret dry weight from 4 to 6 weeks after the treatments than the natural daylength. The treatments, however, decreased no. of flowered florets and ratio of flowering plants although all the treatments showed nearly the same no. of total florets per plant until 6 weeks after the treatments, late October, which resulted in the modification of source to sink or vice versa. In the natural daylength, the florets were functioned as sink, while root, leaf and bract as source, but in the long-day and night-break treatments stem and florets were done as sink.

• Journal of Life Science
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• v.14 no.4
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• pp.689-695
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• 2004

This study was investigate the occurrence of bottom rot caused by Rhizoctonia solani at the crisphead lettuce fields in Uiryeong-gun, Gyeongsangnam-do from November to December in 2003. Incidence of bottom rot on crisphead lettuce was up to 5.3% at the six plastic houses. A total of 30 isolates of R. solani were obtained from diseased leaves of plants and were tested by artificial inoculation to the host. Among them, PY-1 isolate was selected showing highly virulent on the whole plant and was identified as R. solani AG1 (IB) based on the anastomosis test, morphological and cultural characteristics. Symptoms of bottom rot by PY-1 isolate produced small dark brown, depressed and elliptical spots on the lower part of leaves in the early stage as same as at the fields, were enlarged onto the upper part of leaves later, and the infected plant wilted and ultimately died in the end. For the pathogenicity test, triturated mycelia-inoculum (A$_{550}$=1.0) of PY-1 isolate was selected the most effective inoculum showing disease incidence of 51.1% for the mycelial inoculation at pot assay. Otherwise, WSRP media-inoculum (wheat brane ： sawdust ： rice brane ： PDB media=30 g ： 10 g ： 10 g ： 100 ml, w/w/w/v) of PY-1 isolate was effectual inoculum showing disease incidence of 61.6% for soil inoculation at the plastic house. Also, in selection of density and amount of inoculum, most suitable density of triturated mycelia-inoculum and amount of WSRP media- inoculum were determined as $A_{550}$=1.0 and 40 ml, respectively. This is the first report on the pathogenicity test using by WSRP media-inoculum of R. solani PY-1 isolate for the bottom rot of crisphead lettuce.