• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.32-39
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• 2007

This study was carried out to find the optimum treatment condition for the improving germination using the plant growth regulators with $GA_3$ and BAP, to Kentucky bluegrass and Tall fescue showing low germination. $GA_3$ treatment was more effective on the germination of Kentucky bluegrass than BAP single treatment or the combination treatment of $GA_3$ and BAP, regardless of their treatment concentration. Seed germinability was 6 days treatment was significantly better than that of 3 days treatment in the experiment for treatment period of the plant growth regulators. When seeds were treated with $1000{\mu}M$ of $GA_3$ for 6 days, on the percent germination was improved as much as between 10% and 38% comparing with the control. In Tall fescue seed, the percent germination was not significantly improved, although it was slightly increased when the plant growth regulators were treated. For the optimum condition, on percent germination was improved as much as 10% comparing with the control of Tall fescue treated with $1000{\mu}M$ of $GA_3$ for 3 days. Percent emergence fur the seeds of Kentucky bluegrass and Tall fescue treated $GA_3$ in the field was improved as much as $8{\sim}9%$ comparing with the control, and mean emergence time $(E_{50})$ was also faster for $1{\sim}2$ days than that of the control. However, dry weight, plant height and root length showed no significant effects, although those were slightly improved more than those of the control.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.424-431
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• 2017

This study was conducted to set the optimum nutrient solution concentration by growth stage for new strawberry cultivars 'Berrystar' and 'Jukhyang'(Fragaria ${\times}$ ananassa Duch. cvs. 'Berrystar', 'Jukhyang') grown through hydroponics to improve the quality and yield. Three different EC levels were applied to the nutrient solution. The treatment levels were 0.7, 1.0 and 1.3 times higher than the nutrient concentration standard for 'Seolhyang' based on the 'Manual for strawberry cultivation' of Rural Development Administration. Based on the results, there were no significant differences in growth of 'Berrystar' by EC level. 'Jukhyang' showed the most vigorous growth grown in 1.3 times higher nutrient concentration. While the growth of 'Berrystar' and 'Jukhyang' grown in higher EC level has leaves with more chlorophyll concentration. However the quantum yield of leaves was not affected by the treatments. On the treatment with 1.3 times higher EC level, the weight, length, width and firmness of 'Berrystar' and 'Jukhyang' were significantly high. The sugar contents of the harvest analyzed by HPLC did not differed particularly, but the percentage composition of reducing sugar and non-reducing sugar were presented differently depending on the treatments. Marketable fruit yield increased as nutrient concentration increases. However, there were no large differences by treatments. Meanwhile, 'Jukhyang' showed significant difference by nutrient concentration and had the largest yield for a treatment grown in 1.3 times higher EC level. Based on these results, it is recommended to provide the same nutrient solution concentration level to the nutrient concentration standard of 'Seolhyang' for 'Berrystar', and the 1.3 times higher level for 'Jukhyang'.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.366-376
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• 2023

This study was conducted to develop a model for predicting the growth of kimchi cabbage using image data and environmental data. Kimchi cabbages of the 'Cheongmyeong Gaual' variety were planted three times on July 11th, July 19th, and July 27th at a test field located at Pyeongchang-gun, Gangwon-do (37°37' N 128°32' E, 510 elevation), and data on growth, images, and environmental conditions were collected until September 12th. To select key factors for the kimchi cabbage growth prediction model, a correlation analysis was conducted using the collected growth data and meteorological data. The correlation coefficient between fresh weight and growth degree days (GDD) and between fresh weight and integrated solar radiation showed a high correlation coefficient of 0.88. Additionally, fresh weight had significant correlations with height and leaf area of kimchi cabbages, with correlation coefficients of 0.78 and 0.79, respectively. Canopy coverage was selected from the image data and GDD was selected from the environmental data based on references from previous researches. A prediction model for kimchi cabbage of biomass, leaf count, and leaf area was developed by combining GDD, canopy coverage and growth data. Single-factor models, including quadratic, sigmoid, and logistic models, were created and the sigmoid prediction model showed the best explanatory power according to the evaluation results. Developing a multi-factor growth prediction model by combining GDD and canopy coverage resulted in improved determination coefficients of 0.9, 0.95, and 0.89 for biomass, leaf count, and leaf area, respectively, compared to single-factor prediction models. To validate the developed model, validation was conducted and the determination coefficient between measured and predicted fresh weight was 0.91, with an RMSE of 134.2 g, indicating high prediction accuracy. In the past, kimchi cabbage growth prediction was often based on meteorological or image data, which resulted in low predictive accuracy due to the inability to reflect on-site conditions or the heading up of kimchi cabbage. Combining these two prediction methods is expected to enhance the accuracy of crop yield predictions by compensating for the weaknesses of each observation method.

• Microbiology and Biotechnology Letters
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• v.33 no.1
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• pp.41-50
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• 2005

An organic acid tolerance mutant (M-200) was obtained from Leuconostoc mesenteroides KCCM 35471, followed by the screening procedure using a specific organic acid medium (lactic acid: acetic acid, 2:1). The characteristics of the acid tolerance M-200 and the wild type LM-W were examined at various temperature and pH ranges $(l0-30^{\circ}C$ of temp, 3.5-4.5 of pH). The growth of strain M-200 at HCl adjusted medium $(10^{\circ}C\;and\;pH 3.5)$ was observed. In the case of organic acid adjusted medium, the strain showed its growth at the pH range of 3.8. When the strain M-200 was used as a starter for Kimchi fermentation, a constant acid level (0.55) was observed during the whole fermentation period. This result indicates that the strain produces a proper level of acid content for the Kimchi fermentation. This result also indicates that the edible period of Kimchi can be extended to 3.5 fold compare to the result obtained from the LM-W used Kimchi fermentation. However the excess use of the strain M-200 showed the inhibition of growth of Lactobacillus plantarum, low lactic acid level content and low level of organoleptic test. In the case of organic acid content during the Kimchi fermentation, the strain M-200 showed relatively low production rate compare to the wild type (M-200: 3.5 mg/L at 21 days of fermentation, LM-W: 7 mg/L at 21 days of fermentation). Therefore a mixed Kimchi starter containing M-200 and other strains probably maintain a good Kimchi quality during the fermentation.

• Journal of Bio-Environment Control
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• v.7 no.3
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• pp.191-205
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• 1998

Among cauliflower, ‘Snow king’ and ‘Snow crown’, which are early maturing cultivars, showed active early vegetative growth. However, ‘Snow dress’ showed good curd characteristics and in marketability, ‘Green beauty’was superior and can also be grown in Cheju. All the cauliflower and broccoli Plots transplanted on Sep. 3 and on Sep. 17 had fewer number of days from the planting date to the harvesting date than did the plots transplanted on Oct. 1. h the case of broccoli, those transplanted on Oct. 1 had the highest marketability. In the case of cauliflower cultivars, ‘Snow dress’a late maturing cultivar, demonstrated the greatest reduction in growing stage when cultivated in an unheated plastic film houses and broccoli, growing stage is similar between those grown in an open field and those grown in unheated plastic film houses. For all the cauliflower and broccoli, the contents of vitamin A and C showed no significant difference between those grown in an open field and those grown in unheated plastic film houses.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.387-393
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• 2011

This study was conducted to find the effects of microclimates such as air and soil temperature, photosynthetic photon flux density (PPFD) on the berry development and physiological property between cultivation conditions (open field and rain shelter house) in 'Northland' blueberries (Vaccinium corymbosum). The rate of berry growth and development was stimulated in plants grown in rain shelter house, thus, berry reached to the ripe stage about one week earlier than those in open field. Berry weight and size at ripe stage seemed not affected by microclimates. However, total soluble solids content was higher in berries from open field whereas the titratable acidity was significantly higher in berries grown in rain shelter house. Berry firmness at ripe stage was little affected by growing condition. Total anthocyanin content of ripe berries was higher in berries harvested from rain shelter house. Total phenolics content and anti-oxidation activity of berries were higher in open field than those of rain shelter house during berry development but no differences were found at ripe berries.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.328-335
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• 2023

For appropriate nutrient management and enhanced plant growth, soil sensors which reflect soil nutrient levels are required. Because there is no available sensor for nutrient monitoring, electrical conductivity (EC) sensor can be used to evaluate soil nutrient levels. Soil nutrient management using EC sensors would be possible by understanding the relationship between sensor EC values and soil temperature, moisture, and nutrient content. However, the relationship between soil sensor EC values and plant available nutrients was not investigated. Therefore, the objectives of the study were to evaluate effect of different amount of urea on soil EC monitored by sensors during pepper and broccoli cultivation and to predict the plant available nutrient contents in soil. During the cultivation period, soil was collected periodically for analyzing pH and EC, and the available nutrient contents. The sensor EC value increased as the moisture content increased, and low fertilizer treated soil showed the lowest EC value. Principal component analysis was performed to determine the relationship between sensor EC and available nutrients in soil. Sensor EC showed a strong positive correlation with nitrate nitrogen and available Ca. In addition, sum of available nutrients such as Ca, Mg, K, P, S and N was positively related to the sensor EC values. Therefore, EC sensors in open field can be used to predict plant available nutrient levels for proper management of the soil.

• Journal of Mushroom
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• v.14 no.2
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• pp.39-43
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• 2016

In this study, we observed differences in the fruit body genesis in with seasonal changes. The mushrooms generated different spines even when under same environmental conditions in equivalent growth chambers during different seasons. The growth chamber conditions were set at $18^{\circ}$, 1000 ppm CO and 95% humidity for uniform primordium formation. Following this, the humidity was reduced to 85% during growth and development. The characteristics of the fruit body were measured: yield (weight), length (size), hardness, and chromaticity. Each measure was relatively compared owing standard data for. We investigated the environmental factors to assess the cause of variation in fruit body. Change in temperature and humidity were especially focused on, apart from climate that can affect mushroom growth. It was observed that temperature and humidity both influence fruit body growth. Not the absolute value of the elevation, there was a change of climate which the temperature is lowered and lowered the humidity can be assumed that the changes in the environmental conditions inside the growth chamber the mushroom growth.

• Korean journal of applied entomology
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• v.18 no.1 s.38
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• pp.15-21
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• 1979

To determine the population regulation mechanism of the Green rice leafhopper (Nephotettix cincticeps Uhler), the responses of the population increase to initial densities and the effect of host conditions and temperatures during developmental period were investigated. In the out door experiment, the increasing ratio of population density of this pest was reduced as initial density increased and this density-dependent effect was differ in accordance with host condition. Host conditioning through feeding resulted in reduction in numbers of eggs produced and it seemed to be affected by some inhibiting materials secreted by the pest during feeding. though the direct effect of feeding can't be excluded. The population growth was related with population density and host stage. Thus in late planted units, the host stage was favourable to the growth of population at low initial insect density but unfavourable at relatively high initial insect density and in early planted units, vice versa. The temperature during developmental stages definitely affected the determination of sex ratio of adult population and reduced numbers of eggs produced. The most favourable temperature to the population increase was $290^{\circ}C$, and at high temperature, $33^{\circ}C$, severe reduction of fecundity was shown ana it seemed to be caused by the simple reduction in numbers of eggs produced.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.48-56
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• 2023

High-pressure sodium (HPS) lamps have been widely used as a useful supplemental light source to emit sufficient photosynthetically active radiation and provide a radiant heat, which contribute the heat requirement in greenhouses. The objective of this study to analyze the thermal characteristics of HPS lamp and thermal behavior in supplemented greenhouse, and evaluate the performance of a horizontal leaf temperature of sweet pepper plants using computational fluid dynamics (CFD) simulation. We simulated horizontal leaf temperature on upper canopy according to three growth stage scenarios, which represented 1.0, 1.6, and 2.2 plant height, respectively. We also measured vertical leaf and air temperature accompanied by heat generation of HPS lamps. There was large leaf to air temperature differential due to non-uniformity in temperature. In our numerical calculation, thermal energy of HPS lamps contributed of 50.1% the total heat requirement on Dec. 2022. The CFD model was validated by comparing measured and simulated data at the same operating condition. Mean absolute error and root mean square error were below 0.5, which means the CFD simulation values were highly accurate. Our result about vertical leaf and air temperature can be used in decision making for efficient thermal energy management and crop growth.