• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.93-99
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• 2015

The purpose of this study was to determine the appropriate temperature for water curtain in greenhouses equipped with recirculated water curtain system. The study analyzed the changes in air temperature in non-heated greenhouses for strawberry cultivation based on outdoor temperature, water curtain temperature and night time. Three greenhouse units were used for this study: The first unit was assigned as a control (no water curtain system), two other greenhouses were equipped with recirculated water curtain system with water curtain temperatures of $10^{\circ}C$ and $15^{\circ}C$, respectively. Analysis showed that the indoor temperatures were directly correlated with the outdoor temperature in all experimental greenhouses. Heat insulating effect of $15^{\circ}C$ water curtain was increased by $1.3^{\circ}C$ compared to that in $10^{\circ}C$ water curtain system. The $15^{\circ}C$ water curtain treatment showed the highest average temperature and less temperature variation in comparison with control and $10^{\circ}C$ water curtain treatment. To maintain indoor temperature at $5^{\circ}C$, water curtain temperature of $10^{\circ}C$ was suitable when outdoor minimum and average temperatures were -1.3 and $1.5^{\circ}C$, and water curtain temperature of $15^{\circ}C$ was suitable when outdoor minimum and average temperatures were -4.7 and $-0.2^{\circ}C$, respectively. The highest temperature in greenhouses according to measurements in different periods of night time was observed after sunset (18:30-20:30), and the lowest temperature before sunrise (05:00-07:00). Water curtain maintained a target indoor temperature by acting as a layer of heat transfer insulator which decreased heat loss from greenhouses. Therefore, water temperature in recirculating water curtain systems should be determined by considering outdoor temperatures, changes in temperature at different periods of night time, and cultivated crop.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.73-80
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• 2011

To investigate the characteristics of plant growth and flower quality of gerbera 'Sunny Lemon' by amount of nutrient solution, young seedling plants, 'Sunny Lemon' were transplanted to rock-wool and medium of peat moss and perlite mixed with 1 to 2 and they were acclimatized in greenhouse during about 1 month. Nutrient solution supplied to the plants is sonneveld solution of 1/2 concentration and treatments launched June 24, 2010 when average plant height was $20{\pm}1cm$. Nutrient contents as a standard for starting point of irrigation by time domain reflectometry (TDR) were determined with 60-65%, 70-75%, and 80-85%. Results of growth during vegetative growth, plant height, leaf width and leaf number increased by 10% in rockwool, but they were not significantly different. As for plant growth depending on nutrient content, 80-85% treatment showed the highest values. Leaf number increased by 60%, and leaf width and plant height had a about 40% increase than initial growth. Effectiveness for flower quality, yield and days to flowering were superior when nutrient content of media was higher than in the others. Especially, average days to flowering in 80-85% content was advanced by 7-10 days compared to the day in 60-65% treatment. The total amount of nutrient supply per plant was higher in mixed medium than in rockwool, but change patterns of EC and pH were enhanced in rockwool. Based on our results, we recommended that growth, cut flower, and yield of gerbera 'Sunny Lemon' were more effective when nutrient content of mixed medium was maintained at 80-85%.

• Journal of Bio-Environment Control
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• v.4 no.2
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• pp.131-135
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• 1995

In winter, most of the energy for a greenhouse crop is supplied during the night. Since watermelon is grown under high night temperature, the experiments were set up to investigate night temperature influence on watermelon in order to obtain the best economic output. Day temperatures ranged from $25^{\circ}C$ and 3$0^{\circ}C$ ; night temperatures ranged from 2$0^{\circ}C$ to 3$0^{\circ}C$ at 5$^{\circ}C$ interval. Two cultivars of watermelon(Citrullus vulgaris S. ‘Binna’ and ‘Kamro’) treated with 30/3$0^{\circ}C$ yielded maximum leaf areas, flowers and leaf numbers. 30(14h)/25(10h)$^{\circ}C$ or 30(12h)/25(12h)$^{\circ}C$ grown plants had higher germination ratio and more dry weight and chlorophyll than those of 30/3$0^{\circ}C$ which were the highest temperature integral. Although 25/$25^{\circ}C$ and 30/2$0^{\circ}C$ regime are same average temperature, the growth of watermelons at 30/2$0^{\circ}C$ was significantly higher than 25/$25^{\circ}C$. ‘Binna’ was growing more than ‘Kamro’ at the same temperature. Leaf area ratio(LAR) was reduced with increasing DIF temperature from 30/3$0^{\circ}C$ to 30/2$0^{\circ}C$, but leaf weight ratio(LWR) was increased.

• Journal of Plant Biotechnology
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• v.42 no.4
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• pp.370-375
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• 2015

This experiment compared the regeneration conditions of the radiation mutant spray chrysanthemum 'purple ND'. The four different flower blooming stages (S1: 10% opened flower, S2: 30% opened flower, S3: 50% opened flower, and S4: 70% opened flower) and different petal parts (TBOP: the basal of petal and TEOP: the end of petal) were used to compare regeneration conditions between plants grown in MS medium supplemented with IAA and BAP. The highest adventitious shooting rate was identified in plants grown on the IAA $1.0mg{\cdot}L^{-1}$ and BAP $2.0mg{\cdot}L^{-1}$ when using the end of petal at the S2 stage. It displayed 79.2% regeneration and produced 33.4 shoots. Rooted plantlets were successfully established in the greenhouse, showing the same morphological characteristics of vegetative and reproductive organs with those of the mother plant. Flow cytometry analysis revealed no ploidy variation between the regenerated plants and the mother plant grown under greenhouse conditions.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.492-496
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• 2012

Fertigation with drip irrigation provides effective and cost-efficient way to supply both nutrient and water to crop. However, inappropriate management of fertigation systems may cause inefficient nutrient and water use, thereby diminishing expected yield benefits as well as contributing to deterioration of soil properties. In this study, greenhouse experiments were conducted to investigate the optimal concentration of N, P and K fertigation solution for maximum production of oriental melon (Cucumis melo L.) using a response surface methodology, to evaluate an efficiency of nutrients uptake and an effect on soil chemical properties. Canonical analysis of response surface and contour plot interpretation revealed that $108.3mg\;L^{-1}$ of nitrogen (N), $54.8mg\;L^{-1}$ of phosphorous (P) and $158.3mg\;L^{-1}$ of potassium (K) resulted in maximim yield of oriental melon ($2,966kg\;10a^{-1}$). Compared to conventional practice, fertigation increased fruit yield up to 23.0% (p<0.001), uptake of N and K by plant also up to 33.3% (p<0.001) and 15.7% (p<0.01), respectively. These results suggest that fertigation has the advantage of the increase in yield and fertilizer use efficiency.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.83-89
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• 2008

A wind tunnel test was conducted at Protected Horticulture Experiment Station of National Horticultural Research Institute in Busan to find the aerodynamic resistance and quadratic resistance coefficient of chrysanthemum in greenhouse. The internal plants of the CFD model has been designed as a porous media because of the complexity of its physical shapes. Then the aerodynamic resistance value should be input for analyzing CFD model that crop is considered while the value varies by crops. In this study, the aerodynamic resistance value of chrysanthemum canopy was preliminarily found through wind tunnel test. The static pressure at windward increased as wind velocity and planting density increased. The static pressure at leeward decreased as wind velocity increased but was not significantly affected by planting density. The difference of static pressure between windward and leeward increased as wind velocity and planting density increased. The aerodynamic resistance value of chrysanthemum canopy was found to be 0.22 which will be used later as the input data of Fluent CFD model. When the planting distances were $9{\times}9\;cm$, $11{\times}11\;cm$, and $13{\times}13\;cm$, the quadratic resistance coefficients of porous media were found to be 2.22, 1.81, and 1.07, respectively. These values will be used later as the input data of CFX CFD model.

• Korean journal of applied entomology
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• v.52 no.3
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• pp.243-248
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• 2013

This study was conducted to understand the settlement process of Ascotis selenaria larvae into citrus orchards with respect to oviposition site and analysis of the spatial distribution pattern of the larvae. A. selenaria eggs were not found on citrus trees in field and green house, but not on citrus trees in the field. A. selenaria larvae showed a significant clump distribution in the greenhouse. In the open citrus field, the index of dispersion was around 1.0 in most cases, with a weak clumping degree. However, the d-statistic was between -1.96 and 1.96, indicating a statistically significant random distribution. In addition, the Green's index (a clumping index) was very low in all cases, even though the clump distribution was accepted. for most samples, the probability distribution of larval frequency in the field satisfied the probability distribution functions of Poisson (random pattern) and the negative binomial (clump pattern) distribution. In addition, the temporal distribution of the larvae in the open field showed a pattern which was formed by colonizers from outside oviposition sites. Further, the difference in larval spatial distribution between field and greenhouse orchards was discussed.

• Korean journal of applied entomology
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• v.53 no.3
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• pp.231-237
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• 2014

This study was carried out to investigate the pest species and their damage on Asparagus officinalis. Field surveys were conducted in asparagus greenhouse in Jeju, for four years from 2007 to 2010. Total of 16 pest species belonging to 5 orders were found as follows: Thrips tabaci, Thrips hawaiiensis, Adoxophyes honmai, Spodoptera litura, Spodoptera exigua, Helicoverpa armigera, Mamestra brassicae, Ascotis selenaria, Ectropis excellens, Geisha distinctissima, Aphis gossypii, Myzus persicae, Anomala albopilosa, Crioceris quatuordecimpunctata, Acusta despecta sieboldiana and Deroceras reticulatum. Among them, T. tabaci frequently occurred and damaged asparagus plants during the whole growing seasons. C. quatuordecimpunctata and snails caused severe damages on asparagus shoots in spring harvest season. In mid-late seasons, aphids and lepidopteran species occurred and attacked asparagus plants. Of the lepidopteran pests, S. litura, S exigua and H. armigera belonging to Noctuidae occurred moderately and fed on asparagus plants. And the pest control strategy in asparagus cultivation was discussed based on the present results.

• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.217-226
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• 2006

As the results achieved by the evaluation of toxicities on an aphid parasitoid, Aphidius colemani by 79 pesticides registered as horticultural pesticide and 4 adjuvants far pest control, 6 insecticides including a-cypermethrin, 13 fungicides including metalaxyl-M+mancozeb and 4 acaricides including bifenazate showed low toxicity against A. colemani adult. Low toxicity was showed in all the 4 adjuvants as well. In residual toxicity test from 40 pesticides which showed toxicity more than 50%, A. colemani was safe from 11 pesticides from the 3th day after treatment, 7 pesticides from the 5th day after treatment and 14 pesticides from the 7th day after treatment, respectively. But, chlorpyrifos-methyl, diflubenzuron+chlorpyrifos, etofenprox+diazinone and imidachloprid+chlorpyrifos showed high toxicities reaching 100%, 97.7%, 100% and 100% respectively, even from the 7th day after treatment. To evaluate the control effect by A. colemani against Myzus persicae in a greenhouse, A. colemani was released at parasitoid versus aphids rates of 1:50 and 1:100 when the population of M persicae was 50 per plant. After release, aphids population remained steady for 20 days after release at the level of around 60 aphids per plant. During the investigation, insecticides fur thrips control and fungicides for powdery mildew control were treated, but didn't affect the mummy forming of A. colemani. It may be suggested from these results that the selected insecticides, fungicides, acaricides and adjuvent could be incorporated into the integrated M. persicae management system with A. colemani on greenhouse cultivation.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.1
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• pp.25-33
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• 2021

This experiment was conducted to determine the effects of the pre- and post-harvest variable factors on the processed product of kimchi cabbage cultivated in semi-highland at summer time. Kimchi cabbage cultivar 'Chun Gwang' was grown in an open field and/or under a plastic greenhouse condition; it was stored at 0? after harvesting with low-density polyethylene (LDPE) film packaging. The pre-harvest characteristics growth parameters, fresh weight, head weight, no of leaves, leaf thickness, firmness, moisture content etc. were evaluated. The evaluated postharvest characteristics were fresh weight loss, appearance, trimming loss, SPAD value, moisture content and hue angle. The results show that the fresh weight and leaf thickness were higher in 'Chun Gwang' kimchi cabbages grown in the greenhouse than those in the field. However, the other evaluated factors were not affected by the type of cultural method. During the storage, the cabbage continued to decrease in fresh weight loss, trimming loss and moisture content. When compared to the kimchi cabbage showed significant difference in the fresh weight loss, trimming loss and moisture content during storage. It was confirmed that both cultural methods indoor- and outdoor did not show head growth parameters of 'Chun Gwang' kimchi cabbages on semi-high land at summer time. Although no difference in the growth before storage was observed, the evaluated characteristics like fresh weight loss etc. were influenced by cultural method as a pre-harvest factor. This study suggests that there were to be affected by pre-harvest factor during storage after harvest. In this study, an integrated management system combining relationship between processed agricultural products and their pre- and post-harvest factors.