• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.4
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• pp.471-475
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• 1987

Some physiological analysis and the trend of a change in mineral nutrient contents in 2 years old ginseng plants were investigated for 10 times at 15 to 25 days interval from April 25th to October 10. The growth of leaf in size was completed by the beginning of June and that of stem in height by the late of June. The trend of a seasonal change in root weight showed a form of V letter, that is, the weight was de-creased until late of May and increased continuously thereafter up to September. However, the duration of root growth might be dependent on the defoliation. The growth of root in length begins from the beginning of June and stops in the beginning of August. Relative growth rate, net assimilation rate and crop growth rate were all negative values in just after shoot-emergence. The values showed a peak in May and decreased gradually thereafter. The leaf area ratio showed a peak of 76$\textrm{cm}^2$/g in May, and down to 30$\textrm{cm}^2$ /g in the beginning of October. The contents of nitrogen and potassium in aerial part of ginseng plants decreased at the late growing season, but increased on lime. No seasonal changes on phosphate and magnesium were observed. The contents of nitrogen, phosphate and potassium in root decreased rapidly at the maximum growing season for the aerial part and increased gradually thereafter. Whereas no changes on lime and magesium were observed during the growing season.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.3
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• pp.207-213
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• 2010

Changes of heading response and leaf production of winter cereals according to cultivar and sowing date in spring, were investigated in Suwon Korea during three years from 2007 to 2009 to obtain information on use as spring living mulch of winter cereals for weed suppression without herbicide in environment-friendly crop production. Rye showed variation among cultivar in heading response according to sowing date, which means that cultivar selection for living mulch is important in rye. Cultivar Prima and Wintergreen had not headed in sowing during March with low soil temperature in contrast to cultivar Koolgrazer and Gokwoo which had headed somewhat even until sowing in early May with relative high soil temperature. Barley and wheat showed distinct characteristics in heading response between sowing before and after early April compared to rye. Leaf production for soil covering was higher in barley than wheat, and cultivar Mirak than Ol within barley in 2007, respectively. Leaf production were not different much among rye cultivar in sowing during early or mid April, but it was different in sowing after mid April indicating that winter cereal cultivar with high leaf production could be selected in late sowing. It is thought that rye cultivar Duru was the most proper cultivar for spring living mulch in the point of high leaf production in addition to low heading in sowing after March.

• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.300-305
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• 2007

Soil erosion is one of the most serious problems in alpine upland in Korea. Soil fertility has continuously decreased due to serious soil erosion. To increase soil fertility, new sources of organic matter should be inputted. Therefore, the objectives of this research were to select winter cover crop as new sources of organic matter and to investigate the effect of winter cover crop on soil property changes, major crop productivity (Chinese cabbage, potato) production in highland, and disease occurrence with different cropping systems. Among 17 candidates for winter coverage crop, rye was most suitable due to it's soil covering rate, and over-wintering rate. The optimum sowing period for rye ranged from late August to late September. Soil porosity and organic matter content increased with rye cultivation. Rye cultivation during winter increased amounts of crop (both Chinese cabbage and potato) productivity up to 8%. There was little difference on amount of crop productivity depending on cropping systems such as monoculture (Chinese cabbage or potato) and Chinese cabbage-potato rotation.

• Korean Journal of Environmental Biology
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• v.23 no.3 s.59
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• pp.304-314
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• 2005

The occurrence of cyanobacterial bloom in Korean lakes of the summer is generalized. The characteristic of cyanobacterial community was explored. And the developmental stage of cyanobacterial bloom was divided into three phases, 'preparatory phase', 'bloom phase' and 'extinction phase' Cyanobacterial bloom started during the end of June at site 1, transition Bone of Lake Daecheong. The period of water bloom in normal year was about 60~70 days at site 4, lacustrine Bone, but it was unusually 11 days from July 19 in 1999. M. aerugilnosa first occurred in June, had a peak of standing crop curve from the end of August to the beginning of September in 1998 and 2002 and the end of July in 1999 and 2001. The standing crop of M. aeruginosa occupied $68.1\%$ of phytoplankton, $74.2\%$ of cyanobacteria and $88.8\%$ of genus Microcystis, Anabaena spp. first occurred in April, was above 10,000 cells $mL^{-1}$ from the end of August to about the middle of September in 1998. The effect of rainfalls on cyanobacterial bloom was different according to the phases. The rainfalls of preparatory phase assist the growth of cyanobacteria, but accelerate the decrease of cyanobacteria in extinction phase. In bloom phase, the heavy rainfalls reduce the development of the bloom, while the slight ones display only a little effects.

• Korean Journal of Ecology and Environment
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• v.50 no.3
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• pp.305-313
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• 2017

We investigate that the impact of freshwater organism exposed to the salinity environment by the frequent rainfall following climate change. To evaluate the stress response following salinity exposure, we assessed the survival rate, molting success rate, the developmental period and mouthpart deformities in Chironomus riparius. In addition, we measured the molecular responses of biomarker gene, gene expression of heat shock protein 70 (HSP70) in C. riparius exposed to salinity after 96 hour. The C. riparius survival rates were showed on time dependent manner and not observed survival organisms above 15 psu at day 4. The pupation and emergence of C. riparius were not seen above 15 psu, and the molting success rate was less than 20% at 10 psu. The developmental retardation of C. riparius was well observed in the pupation and emergence period and was delayed by 4 days at 10 psu compared to the control and 5 psu. The mouthpart deformities after salinity exposure at 96 or 72 hour were observed at 10 psu and 15 psu. The expression of C. riparius HSP70 level was significantly increased exposure to 5 psu and 10 psu. Thus, salinity has been caused to be various ecotoxicological and molecular stress responses on freshwater organisms similar to harmful substances such as EDCs and so on.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.81-85
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• 1989

One of the most important cultural techniques of pearl millet (Pennisetum americanum (L.) Leeke) is to encourage rapid and uniform emergence of seedlings to establish good stand and to let them grow well. Thus the objectives of the study were to investigate the effects of pre-sowing seed soaking and planting depth on dormancy breaking, germination and emergence of the seedlings, and to estimate the optimum planting season of pearl millet in Suwon, Korea. The seeds with dormancy germinated 99 to 100 percent when soaked in the H$_2$O$_2$ 1％ solution for 24 hours and rinsed with pure water, but germinated only 38％ and 83％ when soaked in pure water for 24 hours just after harvest and drying, and one month later from the harvest time, respectively. The seeds of Australia inbred line did not germinate at the constant 10$^{\circ}C$, but germinated at the constant 11$^{\circ}C$. It also was possible to estimate the optimum planting season by applying minimum temperature 11$^{\circ}C$ for germination. The minimum air temperature reached from late April in Suwon, Korea in regular years but fluctuated from late April to early May in 1986 and 1987. Thus, the safe planting season was mid-May for rapid and uniform germination of pearl millet seed. The optimum depth of planting was 2∼4cm under the optimum soil moisture condition, and 4 to 6 cm under the drier soil moisture condition. Subcoleoptile internode(mesocotyle) length increased according to increased depth of planting. Seedling crown placement also became deeper due to deeper planting of the seeds. The subcoleoptile internode length and seedling crown depth were positively correlated with actual planting depth, indicating that deeper planting would be not good for appropriate adventitious root and tiller development.

• The Korean Journal of Pesticide Science
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• v.18 no.3
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• pp.175-180
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• 2014

This study was carried out to determine the economic injury level and economic threshold level on beet (Beta vulgaris L.) infested with Spoladea recurvalis in the plastic greenhouse condition in 2010. The second instar larvae of S. recurvalis were inoculated with 7 different density levels on the each 10 beet plants as a replication. Injury levels of beet leaves and density of S. recurvalis were increased with the inoculation density of S. recurvalis. However, yield and marketable commodity of beet were decreased. Linear relationship between the percent yield reduction (Y) of beet leaves and different infestation densities of S. recurvalis (X) was estimated by the following equation Y = 1.226x + 3.36. Based on the relationships between the densities of S. recurvalis larvae and yield index of beet leaves, the number of second instar larvae which caused 5% loss of yield, economic threshold level was estimated as 1.1 larvae/10 plants for the planting 10 days. The percent yield reduction (Y) of beet roots infested with different densities of S. recurvalis (X) estimated by the following equation Y = 1.537x + 1.4634 after inoculation for 10 days at 3rd harvesting of leaves. Based on the relationships between the densities of S. recurvalis larvae and yield index of beet roots, the number of second instar larvae which caused 5% loss of yield, economic threshold level was estimated as 6.4 larvae/10 plants for the planting 10 days.

• Korean journal of applied entomology
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• v.53 no.1
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• pp.1-6
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• 2014

The pink citrus rust mite, Aculops pelekassi (Keifer) (Acari: Eriophyoidea), is an important pest in the citrus orchards of Jeju, Korea. This study was performed to investigate the seasonal population abundance of A. pelekassi, and the effects of humidity and citrus leaf age on the multiplication of this pest. Relative humidity (RH) significantly affected the longevity and fecundity of A. pelekassi. Longevity was 7.5, 14.5 and 14.6 d and fecundity was 5.4, 21.5, and 27.1 eggs at 33, 75 and 84% RH, respectively. The leaf age of citrus significantly affected the multiplication of A. pelekassi. The population abundance on 40 day-old leaves was much higher more than 3 times that on 10-day old leaves at 4 weeks after introduction. Overwintered A. pelekassi adults between the bud scales of the citrus trees became active in late April; they were found on newly emerged leaves, followed by their settlement on young fruits in mid-June. The population levels of A. pelekassi peaked on the leaves in late June to July, and on the fruits in early August. The results obtained in this study should be useful for the control of A. pelekassi in citrus orchards in Jeju.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.413-417
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• 2002

Mucocele is a mucous retention phenomenon which is caused by a laceration to the duct of minor salivary glands causing extravasation of mucin into the connective tissue forming a cyst-like space. Sialolithiasis of minor salivary glands and chronic obstruction of salivary glands may also cause such a phenomenon. Mucocele is a smooth, rounded sessile mass with diameters varying from 1 to 15mm of sudden appearance. Mucocele tying directly beneath the mucosa may rupture spontaneously and decrease in size, but frequently recurs. Lower lip is most frequently affected, and the mouth floor and buccal vestibule may also be affected. Enucleation of the cyst is needed and removal of minor salivary glands, marsupialization and cryotherapy may also be done. The mucocele frequently recurs after its removal. A 1-year-old female patient visited the hospital with a complaint of a swelling on the lower lip since 4 months before. She had no pain history but 4 months ago, fell and such symptom appeared since then. On her first visit, a bullous solid, opaque lesion of 5mm in diameter was noted. Treatment choice of surgical approach and nonsurgical approach were explained to the guardian. Considering the patient's age, the guardian agreed to a nonsurgical procedure. Treatment was carried out by tieing 3-0 silk to the base of the lesion. One week later, the tie loosened and was re-tied. A week later, the mucocele disappeared. Mucocele on the lower lip may be usually be treated by surgical removal, but this may traumatize the surrounding minor salivary gland causing it to recur. Also, surgicial removal may induce an ischemic change causing sialometaplasia. In case of young patients or children with management problems, non-surgical methods such as this tie method may be used. This tie method does not need any local anesthesia and has no pain, no secondary infection, and low bleeding tendency.

• Korean journal of applied entomology
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• v.40 no.3
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• pp.211-217
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• 2001

Field survey for Orius spp., predacious natural enemies of thrips pests, on several plants by beating or sweeping method revealed that O. sauteri, O. strigicollis, O. minutus, and O. nagaii habituated in open fields or in greenhouses of Korea. Among them, O. sauteri was the most dominant species at all areas (83.0~92.5%), followed by O. strigicollis and O. minutus. Especially, O. sauteri exclusively dominated on the economically important crops such as soybean, red pepper, and watermelon. On the other hand, O. strigicallis and O. nagaii occurred mainly on ornamental plants including chrysanthemum and rose and on rice, respectively, during summer-autumn season. The seasonal occurrence varied depending on the plant. Initial population of Orius spp. was first observed on white clover in late May, followed by on soybean, red pepper, an buck wheat in early June, indcating that movement of Orius spp. relates to the flowering time of the plant. Peak of Orius spp. abundance was found first in July and secondly in August or September. On white clover and buck wheat the first peak of abundance was one week earlier than on soybean and red pepper. Therefore, we suppose that wild plants such as white clover can serve as a reservoir for Orius spp. after overwintering.