• Journal of Bio-Environment Control
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• v.16 no.3
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• pp.240-246
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• 2007

To evaluated the effect of low temperature storage on quality of fresh shoot of Sedum sermentosum, weight loss, Hunter L, a and b value, chlorophyll, water content, and general appearance were investigated during storage at 20, 10, and $5^{\circ}C$. Just after harvesting, fresh shoots ($10{\pm}2cm$ length) were stored with wrap film (linear LDPE)-packaged condition using the Styrofoam dish ($20{\times}10cm$, which 40 fresh shoots per dish). The fresh weight of 40 shoots was gradually decreased according to days after storage and higher storage temperature. The weight loss of fresh shoots showed significant difference (8.7-25.3%) between just before storage and 10 days after storage, and the degree of weight loss was more severer in higher storage temperature. Wanju local strain showed the lowest weight loss, and the most severe case was Pohang local strain. SPAD value related to chlorophyll content was rapidly decreased after 4 and 6 days at 20 and $10^{\circ}C$ storage, respectively. It was slowly decreased according to days after storage at $5^{\circ}C$. Yellowish color in bottom leaves of shoot appeared after 4, 6 and 8 days at 20, 10, and $5^{\circ}C$ storages, respectively. Hunter L and a values were gradually increased after storage, and it showed significant difference between just before storage and 10 days after storage. The total rate of discoloration over 50% or decay shoot was largely increased as higher temperature. It was significantly correlated to the water content of fresh shoot among local strains $(P{\leq}0.01)$. The freshness of shoot after storage was maintained in order of Wanji, Gunsan, Wando and Pohang local strain. The results indicated that the freshness was maintained for 8 days after $5^{\circ}C$ storage, when the fresh shoot was stored with wrap film-packaged condition.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.283-290
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• 2017

In this study, the method to attach plastic film on the side vent from inside of greenhouse for the entire length was developed as the way to make crops less stressful while uniformly getting outside air into the greenhouse when ventilating using roof ventilation fans at single-span plastic greenhouse for oriental melon in a low-temperature period. The plastic film was installed from ground to 10cm below from the height where side vent is fully opened. In order to verify that the improved side vent can improve greenhouse environment and fruit yield, it was compared with the control plot of conventional side vent. Both greenhouses were not ventilated until February 25th, 2017. Air temperature in both greenhouses exceeded $40^{\circ}C$ in mid February. Therefore, it is judged that the greenhouse should be ventilated from mid February. Air temperature in the control plot exceeded $30^{\circ}C$ from late April. Therefore, it is judged that the plastic film attached to the inside of side vent should be removed in late April, or in early May at the latest. Soil temperature in the treatment plot in the mid Aril exceeded $20^{\circ}C$, which is suitable for growth, while that in the control plot was still below $20^{\circ}C$. Soil temperature in the control plot finally exceeded $20^{\circ}C$ in late April. The consumption of electricity was 47.2 kWh in the treatment plot, and 48.3 kWh in the control plot, which was no significant difference. The marketable yield of oriental melon in the treatment plot was 5,094kg, which was 23.9% more than that in the control plot, 4,113kg. The marketable fruit ratio was 73.5% in the treatment plot, and that in the control plot was 73.9%, which was no significant difference.

• Asian Journal of Turfgrass Science
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• v.21 no.1
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• pp.9-21
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• 2007

Research was initiated to examine establishment efficiency of zoysiagrass by plugging. Zoysiagrass is known to be a slowly establishing turfgrass species. Properly-treated zoysiagrass seed can speed up the establishment rate, while initial irrigation practice is intensively required after seeding. A planting method with small plugs($2.5{\times}2.5cm$) from seeding can overcome initial watering requirement. Establishment speed, however, can vary with planting dates, planting spaces, and plastic film cover in early stage. Establishment characteristics were investigated for two years by planting dates that were April 5, May 18, July 13, August 24 and October 29 in 2004 and April 6 in 2005. They were also compared with three different spaces($20{\times}20,\;25{\times}25,\;and\;30{\times}30cm$) and three different fertilizer levels(15, 30, and $45g\;N{\cdot}m^{-2}$). Ground coverage reached to 90% in plugs of 'Zenith' zoysiagrass planted on April 5. It increased suddenly in period of July to August, resulting in about 50% of full establishment rate. Establishment rates were significantly faster over 9% in plugs spaced at $20{\times}25cm$ than in those at $30{\times}30cm$. No significant differences were observed on the stolen number and stolen length in the study. Survival rate in zoysiagrass plug was over 90% at all plantings. These results demonstrated that zoysiagrass establishment using small plug from seeding is considered to be a safe and efficient method.

• Journal of Bio-Environment Control
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• v.4 no.2
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• pp.175-180
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• 1995

This study was conducted to establish the nondestructive nutrient diagnosis method for nitrogen in tomato leaf using SCDS(specific color difference sensor). NFT(nutrient film technique) system was used in this experiment and nitrogen concentrations treated in nutrient solution were 0, 10, 50, 100, 150, 200, 300 and 600ppm. As nitrogen concentration in nutrient solution was increased from 0ppm to 150ppm, the stomatal resistance of tomato leaf was decreased abruptly, the $CO_2$ assimilation rate was increased but there was no big difference in the range of 100-500ppm. As the SCDS value of tomato leaf was increased, the $CO_2$ assimilation rate was increased linearly but the total average fruit weight and marketable yield were increased quadratically. The $CO_2$ assimilation rate was largely increased in the 0-3% range of leaf nitrogen content, but photosynthetic saturation was shown in 3.3-3.5%. The leaf nitrogen content was closely related to SCDS value of tomato leaf. Considering physiological activity, growth and yield of tomato, the optimum ranges of leaf nitrogen content were found to be 3.0-3.8% and the SCDS values equivalent for those ranges were 40.0-52.2.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.204-210
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• 2011

This experiment was conducted to investigate the effect of water states (water, osmotic potential and turgor pressure) of fruit vesicle and leaf on soluble solids and organic acid contents of fruits of 'Shiranuhi' mandarin hybrid, M16 A line during the fruit maturing season in plastic house cultivation. The 'Shirauhi' grafted on 'Swingle citrumelo', strong strength of rootstock, produced fruit with lower soluble solids and organic acid content than 'Trifoliate' orange rootstock. The fruits vesicle water potential and turgor pressure measured before dawn in 'Swingle citrumelo' were higher tendency than the 'Trifoliate' orange, but osmotic potential values were lower than the 'Trifoliate' orange. The changes of leaf water potential were very similar to the fruit. The results suggest that in the 'Shirauhi' fruits grafted on two rootstocks changes of soluble solids and organic acid content of the fruit were influenced by the leaf water potential and the osmotic potential of the fruit vesicles, which might be caused by the difference of root distribution between two rootstocks.

• Journal of Bio-Environment Control
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• v.17 no.3
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• pp.204-209
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• 2008

This experiment was conducted to analysis the fruit quality according to training method under low plastic film greenhouse cultivation on sweet pepper (Capsicum annuum cv Special) during summer culture. Training treatments were upright training and inclination training, the fruits were examined and analysed with a month interval from June to November on productivity, fiuit weight, flesh thickness, contents of soluble solids, hardness, shape, and locules. Productivity per month was the highest on June, upright training harvested more than inclination training. Fruit weight of inclination training on June was 232 g which was higher than 26 g of upright training, but upright training was heavier than inclination training after July. Flesh thickness of upright training was thicker than inclination training. Soluble solids content increased with the decrease of temperature, upright training was higher than inclination training. The fruit shape of upright training was not significant according to harvesting date. The number of locules of upright training was $3.27\sim3.34$, and it was not significant according to harvesting date.

• Journal of Bio-Environment Control
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• v.6 no.3
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• pp.190-197
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• 1997

This study was conducted to determine the optimum hydroponic system and nutrient solution for promoting the growth and flowering of hydroponically grown carnation. DFT (deep flow technique) and NFT (nutrient film technique) systems were employed and four kinds of nutrient solution, which are Cooper solution, Yamasaki solution, balanced nutrient solution by Japanese Horticultural Experiment Station and PTG solution in the Netherlands were used and compared. pH was lowest in the PTG solution compared to the other nutrient solutions used. Plant height was highest in the DFT system in the plot of PTG solution as of 53.0 cm at 88 days after transplanting, while lowest in NFT system with Cooper solution. Stem diameter was more thickened in NFT system with PTG solution as of 7.2 mm at 88 days after transplanting. Days to flowering was shortened to 122.3 days in NFT system when PTG solution was used. This results suggested a combination of NFT system with PTG solution as optimum hydroponic system and nutrient solution for cut carnation production. Further trials as to the management of nutrient solution by glowing stages should be followed.

• Journal of Bio-Environment Control
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• v.8 no.1
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• pp.49-55
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• 1999

This study aims at analyzing environment factors of two tier cropping systems and suggesting effective structures of two tier cropping systems. The environment factors in two tier cropping systems are temperature, relative humidity, solar radiation, temperature of nutrient solution, and wind velocity. Especially, The most important factors are the solar radiation and the solar incident area between the two tiers. During the experiment, observations were made of the two levels in the plastic greenhouse. The highest temperatures were 38.3$^{\circ}C$ in the top level and, 35.5$^{\circ}C$ in the bottom level, respectively. The temperature of the nutrient solution between the two levels showed little difference. The relative humidity in the top level was 60~7o% and that in the bottom 65~80%, exhibiting that the bottom is approximately 10% higher. Change of photosynthetic photon flux density and solar radiation both have a tendency to be similar. The wind velocities for both levels were recorded at 0.1m.s$^{-1}$ in the afternoon and 0.05m.s$^{-1}$ in the evening. The solar incident areas in the bottom level increased by approximately 25% at an East-West position and 17.7% at a South-North position, respectively.

• Journal of Bio-Environment Control
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• v.8 no.1
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• pp.42-48
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• 1999

This study was executed to see the effects of Ca : K ratios in me.L$^{-1}$ -0:9, 1.5:7.5, 3:6, 4.5:4.5, 6:3 - in the nutrient solution on the photosynthesis, transpiration, growth and incidence of tipburn in butterhead ‘Omega’and Leaf ‘Grand Rapids’lettuce (Lactuca sativa. L) grown in nutrient film technique(NFT). The photosynthesis of both lettuces showed high in the Ca : K ratios of 3:6 and 4.5:4.5 regardless of species. But stomatal resistance of Grand Rapids was higher than that of Omega. The highest transpiration rate of them was shown in the Ca : K ratio of 3:6. The transpiration rate of developing leaves was lower than that of expanded leaves. It was seemed to have relation with incidence of tipbum in the developing leaves. The nutrient solution treatment without Ca developed less growth than that of other treatments, especially growth and development of apical part were inhibited, so that in the both of them incidence of tipburn appeared 100 percent. The incidence of tipburn in Omega appeared 25 percent in the Ca/K ratio of 1.5:7.5, but Grand Rapids did not show it according to the Ca/K ratio in nutrient solution. The highest growth in two species was also shown in the Ca/K ratio of 3:6 except nutrient solution without Ca. This study suggested that the unbalanced ratio of Ca/K affected Ca transport in two species because of the increase of stomatal resistance and diffusive resistance and the decrease of photosynthesis and transpiration.

• Journal of Bio-Environment Control
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• v.20 no.1
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• pp.21-26
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• 2011

Differences among cultivars, conditions of nutrient solution, nursing materials, and soilless culture systems were investigated to select suitable cultivar and cultivation methods for stable production of summer spinach in the highlands. The 'Quinto' spinach showed the earliest growth and highest yield. For yield increase of summer spinach, optimal solution pH was 6.0, EC was $2.0dS{\cdot}m^{-1}$, and $NH_4-N$ ratio of nutrient solution was 30 percent Stand rate of spinach in nursing seedlings, at 200-cell-tray filled with mixed nursing soil (peat : perlite = 7 : 3), was higher than those grown in urethane sponge and rock-wool plug. Yield was also 18 to 24 percent higher than those in rock-wool plug and urethane sponge. Plant length and yield of spinach in mixed substrate (peat : perlite = 7 : 3) filled nutrient film technique (MSNFT) system were longer of 18 percent, and higher of 9 percent than those in deep flow technique (DFT) system, respectively. However, changes of root zone temperature, pH and EC showed similar pattern with DFT. Therefore, growing 'Quinto' cultivar at 6.0 of pH, $2.0dS{\cdot}m^{-1}$ of EC, 30 percent of $NH_4-N$ ratio, at 200-cell-tray filled with mixed nursing soil, and MSNFT cultivation system, was the best for production of summer spinach in the highlands.