• Journal of Bio-Environment Control
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• v.14 no.3
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• pp.166-173
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• 2005

This study was carried out to evaluate the structural stability in a non-heating greenhouse with a single cover for Citrus cultivation which was built up in Jeju on the basis of the drawing designed by Jejudo Agricultural Research & Extension Services and also to make use of the data for developing a standardized non-heating greenhouse in Jeju. The analysis of a structural stability was conducted by using CFX-5.7 and ANSYS under the design condition of a maximum accumulated snow-depth of 19.1 cm as well as an instantaneous maximum wind velocity of $36.6\;m{\cdot}s^{-1}$ which was set up on the basis of meteorological statistics in Jeju. As a result, the maximum von-Mises stress applied on pipes under the wind velocity of $36.6\;m{\cdot}s^{-1}$ showed a value of $250\;N{\cdot}mm^{-2}$ which was greater than the allowable stress of the pipe with a value of $235.4\;N{\cdot}mm^{-2}$ (=$2,400\;kg{\cdot}cm^{-2}$) and also $53.8\;N{\cdot}mm^{-2}$ under the snow-depth of 19.1 cm, respectively. This result suggested that the greenhouse be unstable under the design condition of an instantaneous wind velocity of $36.6\;m{\cdot}s^{-1}$ so that it was necessary for the greenhouse to be reinforced to secure the structural stability.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.71-71
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• 2018

본 연구는 각시톱시네고사리(Dryopteris hangchowensis Ching)의 전엽체 증식 및 포자체 형성을 위한 번식방법을 구명하고자 수행되었다. 각시톱지네고사리의 식물체를 무가온 온실에 재배하면서 포자를 채취하였으며, 수집된 포자는 기내에서 발아시켜 전엽체를 획득한 다음 계대배양하면서 실험의 재료로 사용하였다. 전엽체 대량증식을 위하여 1/4, 1/2, 1배로 조절한 MS배지와 Knop배지를 조성하였다. 이후 전엽체 300mg을 균일하게 다져 조성된 배지에 8주간 배양하였다. 연구의 결과, 전엽체의 생체중은 1/2MS와 1/4MS에서 3.4g으로 가장 많이 증가하였다. 현미경 관찰의 결과, 두 배지 모두 정상적인 전엽체의 형태로 발달하였으며, 생육도 양호하였다. 포자체 형성을 위한 적정 배양토의 혼합조건을 확인하고자 원예상토, 피트모스, 펄라이트 및 마사토의 혼합비율을 5종류로 달리하여 조성하였다. 준비된 배양토를 사각분($7.5{\times}7.5{\times}7.5cm$)에 충진 후 기내 배양한 전엽체 1g과 증류수를 함께 10초간 분쇄하여 토양표면에 균일하게 분주한 다음 12주간 재배하였다. 연구의 결과, 원예상토, 피트모스, 펄라이트를 1:1:1(v:v:v) 비율로 혼합한 토양에서 포트 당 223.7개로 가장 많은 포자체가 형성되었다. 또한 형성된 포자체의 생육을 조사한 결과, 상기 토양에서 생체중, 엽수, 엽장, 엽폭, 근수, 근장 및 SPAD value 등의 생육수치가 우수하였다. 따라서 각시톱시네고사리의 전엽체 증식에 적합한 배지는 경제성과 생육수준을 고려하여 1/4MS 배지가 적합하며, 포자체 대량생산을 위해서는 원예상토, 피트모스, 펄라이트를 1:1:1(v:v:v)로 혼합한 토양이 적합하다고 판단되었다.

• Journal of Bio-Environment Control
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• v.14 no.1
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• pp.15-21
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• 2005

This experiment was carried out to investigate the effect of ridge direction (south-north) on temperature and light intensity on early growth of oriental melon under east-west oriented vinyl house cultivation. The air-temperature of minimum between north and south-ridge in the tunnel of vinyl house was $12.5^[\circ}C\;and\;11.3^{\circ}C$ and that of maximum between north and south-ridge was $36.7^{\circ}C\;and\;34.7^{\circ}C$, respectively. The minimum and maximum air-temperature of north-ridge in the tunnel of vinyl house on Feb. 15 were $12^{\circ}C\;and\;2.0^{\circ}C$ higher than those of south-ridge, respectively. The intensity of daylight between south and north-ridge was similar during 9:00-10:30 a.m., that of south-ridge was higher than north-ridge during 10:30-11:30 a.m. and that of north-ridge was higher than south-ridge during 11:30-17:30. The plant growth after 55 days of planting on the north-ridge was prominent cultivation compared to south-ridge. The female flowering and first harvesting day were earlier in north-ridge than in south ridge. The marketable fruits rate and yields (kg/10a) were $6.7\%$ and 218kg higher in north-ridge cultivation than south-ridge, respectively. Differences of marketable fruit rate and yield (kg/10a) in each ridge were significant.

• Journal of Bio-Environment Control
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• v.8 no.1
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• pp.67-73
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• 1999

This experiment was conducted to investigate the effect of thermokeeping bag with 30 and 45cm width on the growth, fruit quality and yield of oriental melon. Difference of the highest temperature was not observed but the lowest temperature of thermokeeping bag with 30cm and 45cm width was higher than that of control by 0.9$^{\circ}C$ and 1.8$^{\circ}C$, respectively The highest soil temperature of thermokeeping bag with 30cm and 45cm width was higher than that of control by 1.9$^{\circ}C$ and 9.9$^{\circ}C$, respectively and the lowest soil temperature of thermokeeping bag with 30cm and 45cm width was higher than that of control by 0.9$^{\circ}C$ and 1.2$^{\circ}C$, respectively. Growth characteristics in terms of stem length, leaf number, leaf area, fresh and dry weight, fruit weight, flesh thickness and soluble solid were higher as the width of thermokeeping bag was winder. Marketable yield per 10a of 30 and 45cm thermokeeping bag was higher 5.3% and 19.2% than that of control with 996.4kg per 0.1ha.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.72-77
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• 2007

This study was conducted to investigate the effect of functional cover film on oriental melon fruit quality under unheated plastic greenhouse cultivation in cold period. The 6 kind of films having different characteristics were covered at plastic greenhouses and oriental melon seedlings were cultivated at 2 regions of Seongju, respectively. The air-temperatures in plastic greenhouses of J-1 and J-2, having high infrared absorption rate, were about $2{\sim}5^{\circ}C$ higher than K-3. The contents of ${\beta}-carotene$ and sugar of fruit showed significant difference between functional and normal films. The sucrose, determining a sweetness during maturation, and soluble solids content of fruits cultivated in J-1, J-2, J-3, and K-1 were higher than those of K-2 and K-3. Ascorbic acid of fruits was highest in K-2 having low light transmission rate and thermo-keeping capacity. There was no significant difference in mineral content among all of cover films. These results indicated that the use of functional greenhouse covering films could improve fruit quality such as ${\beta}-carotene$ and sugar content of oriental melon.

• Journal of Bio-Environment Control
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• v.16 no.2
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• pp.96-100
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• 2007

There was no difference in total light transmissivity of covering materials. But the light transmittance of J-2 in greenhouse was by 78.25 which was higher than any other film. The high light transmittance of J-2 was come from low water condensation and dust attached in film surface. The ultraviolet light of J-3 was completely intercepted. The ultraviolet transmittance rate of others was from 62 to 76%. In no heating oriental melon cultivation, the air temperature in tunnel was 15 to $21^{\circ}C$ higher than outer, and the soil temperature in tunnel was 20 to $25^{\circ}C$ higher than outer. Air temperature and soil temperature of J-2 were higher than any other film.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.4
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• pp.357-360
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• 1997

To fine out the concentration of $SO_2$ gas in plastic film house, the survey was conducted at 343 sites throughout the nation. The $SO_2$ concentration in plastic film house were similar both heating and non-heating, but $SO_2$ cocentration higher than 0.8ppm was detected at those with heating. The $SO_2$ concentration in plastic film house cultivated red-pepper higher than those of cucumber or tomato cultivation, and it was produced higher amounts at day time than night due to the higher temperature. In plastic film house with heating, $SO_2$ was leaked at brocken parts of heater and joint of stove pipe, sometimes, $SO_2$ discharged from smokestack was resucked with air. $SO_2$ concentration in the plastic film house with and without ventilation were 0.2 and 0.6ppm, respectively.

• Korean Journal of Organic Agriculture
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• v.25 no.4
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• pp.773-788
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• 2017

This study was carried out to investigate the damage patterns, the occurrence and migration time of Pseudococcus comstocki and in order to improve the control effect of organic agricultural materials (OAMs). The experiment was carried out at Okcheon's organic vineyard ($2,500m^2$, sandy loam, manure) where planted 8~9 year old 'Muscat of Alexandria' vines. The comstock mealybug's migration to grape clusters occurred from the middle of July, and produced eggs in the grape clusters from the end of July, and the density of the comstock mealybug was highest at $0.6cm^2$ in late August. The number and fruit damage of comstock mealybug in eco-friendly vineyards were higher than in conventional culture vineyard. And the marketability of green variety grape was more damaged from comstock mealybug than the black variety grape. Toxicities of 8 OAMs were evaluated to comstock mealybug at the recommended concentration. As a results, Lightyellow sophora and Derris extracts exhibited strong insecticidal activity with 100% mortality. When the Lightyellow sophora extract was uniformly distributed on the vine from early-July to mid-July, fruit damage reduction rate was 96.2% and 84.6%, respectively. So commercial grapes could be harvested. Therefore, it was considered to be effective to reduce fruit damage by controlling in early - late July (the green stage) when the comstock mealybug migrated to grape clusters in the vine greenhouse. In the future, it will be necessary to study the effect of external exposure time and momentum on the control of OAMs.

• Journal of Bio-Environment Control
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• v.3 no.2
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• pp.119-127
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• 1994

This study was conducted to investigate the effects of temperature and light conditions on the vigor and growth responses of red pepper(Capsicum annuum L.) seedlings in the nonheated plastic houses with triple and quadruple coverings during winter. The results obtained were as follows ; 1. The growth in terms of plant height, number of leaves, leaf area and dry weight of each organ was reduced up to 50% in the triple coverings compared to quadruple ones. The greatest difference between the triple coverings and quadruple ones was the leaf area, showing two to five times larger in the quadruple ones. Therefore, the differences of the early environmental conditions during raising seedling stage was well reflected. 2. The leaf expansion in the early stage of seedling was delayed in the triple coverings and subsequently crop growth rate(CGR) significantly reduced. The specific leaf area (SLA) in the triple coverings was less than quadruple ones. The net assimilation rate (NAR) was increased in the early stage of seedlings and then reduced in the quadruple coverings. In triple ones, however, the great reduction showed at six weeks after sowing and then increased sharply. 3. The linear relationship among leaf area, total dry weight and leaf dry weight was observed in the all experimental areas, while between leaf area and crop growth rate only in the quadruple coverings, and between leaf area and net assimilation rate in both triple and quadruple ones. 4. The dry matter partitioned to the leaf increased up to six weeks after sowing in the triple coverings but reduced in the stem and root. However, the adverse results were obtained in the quadruple ones. 5. In the triple coverings, the number of branches showed the exponential increment while fruit weight showed linear increment in both triple and quadruple ones. Higher yield was obtained in the quadruple ones. 6. The shoot dry weight among the characteristics of seedlings was greatly contributed to the yield of red pepper after transplanting. Accordingly, one of the decisive criterion for good quality of red pepper seedlings was determined by the highest correlation between shoot dry weight of growing plant and fruit yield of pepper plant.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.319-325
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• 2018

The aim of the present study was to determine the influence of different fertilizer combinations on the growth, yield, and fruit quality of 'Duke' blueberry cultivar and the water quality of growth medium. The experiment was carried out with three year old 'Duke' blueberry bushes which were cultivated in containers ($60{\times}80{\times}40cm$) filled with 130 L peat moss and 40 L pearlite (v/v). Sawdust was used as the mulch in growth containers. Three different fertilizer combinations (FC) i.e., FC-1 consisted with standard solution, FC-2 consisted with nitrogen reduced by 10% from FC-1, and FC-3 consisted with nitrogen reduced by 20% from FC-1 were tested while, the ground water used as the control. The effects of different fertilizer combinations on shoot diameter, shoot length, number of shoots, leaf length, SPAD value (the relative content of chlorophyll), berry weight, soluble solids content, titratable acidity, and yield per bush in 'Duke' blueberry were examined. Also, the effects of different fertilizer combinations on pH, EC, $NH_4$ and $NO_3$ in 'Duke' blueberry growth medium were monitored. The highest pH and lowest EC, $NH_4$ and $NO_3$ in growth medium was recorded with control treatment during the experiment period. The maximum shoot diameter (3.7 mm) and shoot length (35.7 cm) was recorded for the FC-1. Highest number of shoots (47%) were recorded from 'Duke' blueberry bushes supplemented with FC-1 compared to other treatments. The fertilizer combinations supplemented with nitrogen showed significant influence on leaf length and SPAD value compared to control 'Duke' blueberry bushes. However, the fruit quality attributes, i.e., berry weight, soluble solids content, and titratable acidity were not significant different among fertilizer treatments. The significantly highest yields per bush were recorded for FC-1, FC-2, and FC-3, as 2.2, 2.9, and 2.7 kg, respectively compared to control (0.2 kg). Although, the FC-1 was supplemented with highest nitrogen content it resulted low yield per bush while having high number of shoots and vigorous growth.