• Journal of Bio-Environment Control
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• v.18 no.2
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• pp.101-106
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• 2009

To study the effect of nonwoven fabric materials on growth and yield of korea melon, Medium denier nonwoven fabrics (MDNF), Polyster nonwoven fabrics (PENF) and 12 ounce nonwoven fabric (control) were used. Mean temperature at night was 13.1$^{\circ}C$ at control, 14.7$^{\circ}C$ at MDNF and 13.3$^{\circ}C$ at PENF from Feb. 6${\sim}$7, 2009. Because of higher temperature, early growth of korea melon of MDNF was better than control at 30 days after transplanting. Days required to harvesting (DRH) of control was 89, those of PENF and MDNF were 88, 78, respectively. First harvesting of MDNF was 11 days earlier than control. Harvested fruit of MDNF had higher weight, soluble solid and marketable fruit ratio than control. Yield ratio of control and PENF was 4:3:3 (early:middle:late harvesting season), but MDNF was 5:3:2. Using of MDNF provided earlier harvesting. Total yield of PENF was similar to control, 1,844kg per lOa, MDNF was increased by 9%.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.125-132
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• 1988

Gulbis were made of raw Pseudosciaena manchurica by different salting methods and drying conditions. During the Gulbi processing, the contents of trimethylamine(TMA), dimethylamine(DMA) and formaldehyde(FA) were chemically analyzed and the distribution of fat was microscopically observed. The contents of TMA, DMA and FA in raw sample were 0.9mg, 3.19mg and 0.19mg per 100g, respectively. The TMA contents in Gulbi were rapidly increased to 24.82-76.32mg during drying, while the DMA contents in Gulbi were slowly increased and FA contents in Gulbi remained nearly unchanged. These changes were not influenced by the kinds of salt and salting methods. The formation rates of TMA and DMA were twice faster dried by the controlled condition than the natural condition. The fat in muscle moved to the skin layer through connective tissue with the laps of drying time. The extent of fat shifting was smaller salted by purified salt than by bay salt. The muscle tissue of Gulbi dried by the controlled condition had clearer spaces between white muscles than that of the natural condition. The muscle tissue of Gulbi salted with purified salt exsisted orderly, while the sample salted with bay salt was clumped.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.392-397
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• 2012

In this study, we investigated the changes of growth characteristics, mineral and chlorophyll content of young leafy vegetable of Chinese toon grown under greenhouse and open fields. Results showed that growth of young leafy vegetable of Chinese toon was somewhat accelerated in greenhouse compared to the open field. In case of apical bud growth, several parameters such as plant height, number of branch, fresh weight and chlorophyll content showed similar tendency in both greenhouse and open field. In the changes of minerals, N content in apical buds recorded significant increase to 3.1 times compared to that of later buds. Its content was 1.2 times higher in greenhouse than that of open field. Mineral contents including P, Ca, Mg and Fe were significantly increased in greenhouse. Highest ascorbic acid content was observed in lateral buds grown in greenhouse and then it was followed such as lateral bud in open field, apical bud in open field, and apical bud in greenhouse, in turn. These results indicate that greenhouse culture could be applicable to new culture in order to produce young leafy vegetable of Chinese toon with high quality.

• Journal of Bio-Environment Control
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• v.9 no.2
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• pp.120-126
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• 2000

The quality of oak mushoom(Lentinus edodes(Berk) Sing) is sensitively affected by environmental factors, especially moisture by the rain during the growing period. To protect mushrooms from being wet, plastic-covered facilities with side openings are mostly being used. However, the indoor temperature and humidity f the facility without roof opening become higher due to its poor ventilation, and consequently reduce the productivity and quality as well. In this study, we analyzed the ventilation rates and indoor temperatures of improved facilities as affected by the area of roof opening and shading rate by the model. The indoor temperature decreased by more than 2.5$^{\circ}C$ as the shading rate increased from 50% to 90%, and especially the effect of wind speed on indoor temperature was significantly great under as low as 50% of shading rate. The ventilation rate became higher under wind speed of 1~2m.s-1 regardless of the shading rate. As the wind speed increased from 0m.s-1 to 2m.s-1, the indoor temperature decreased by more than 2.$0^{\circ}C$. Moreover, the indoor temperature became lower with increasing roof opening ratio, but showed no significant differences at more than 50% of roof opening ratio. At lower shading rate, the indoor temperature sensitively decreased with increasing area of roof opening. Additionally, we obtained the higher ventilation performance with the area of roof opening more or less equal to side opening, regardless of the wind speed and shading rate.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.16-20
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• 2004

Aphis gossypii Glover(Homoptera: Aphididae) is an serious pest on various crops. This experiment was conducted to evaluate the effect of A. gossypii Glover on the growth of oriental melon and the plant recovery after removing A. gossypii. Visible damage symptom caused by A. gossypii feeding to oriental melon was leaf distortion and stunting. A. gossypii feeding for 20 days on oriental melon significantly reduced the growth of oriental melon with increasing A. gossypii density level. Plant growth was decreased by 63${\sim}$69%, 62${\sim}$88% and 49${\sim}$70% in plant height, leaf area and dry weight, respectively. During 10 day after aphids removal, the infested leaves remained stunt, however, new shoot and leaf recovered gradually. By 20 day, plant height, leaf area and dry weight substantially increased in 5 aphid per plant. Plant recovered rapidly with day and among aphid density level, 5 aphid per plant showed rapid recovery. When plant were infested with several density of aphid per plant, sugar contents of total leaves were not significantly different between aphid density level. Whereas, sugar contents of lear infested with aphid per leaf were decreased with increasing cumulative aphid-days.

• Journal of Bio-Environment Control
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• v.10 no.1
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• pp.10-14
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• 2001

The cooling effect of a fog cooling system has a close relationship to air flow and relative humidity in the greenhouse. From the VETH chart for cooling design, a cooling efficiency can be improved by means of increasing the air exchange rate and the amount of sprayed water. In the no shading experimental greenhouse by time control, when average air exchange rate was 0.77 times.min$^{-1}$ and spray water amount was 2,009g, inside temperature of the greenhouse was 31$^{\circ}C$ that was almost close to outside temperature and cooling efficiency was 82%. When average air exchange rate was close to temperature of the greenhouse that was no cooling and 70% shading greenhouse environment. When average air exchange rate was 2.59times.min$^{-1}$ , spray water amount was 2,009g and shading rate was 70%, inside relative humidity of the greenhouse was increased was 2,009 g and shading rate was 70%, inside relative humidity of the greenhouse was increased, but temperature was not decreased. When average air exchange rate was 2.33 times.min$^{-1}$ and spray water amount was 2,009g, inside temperature was 31.4 and at that time maximum wind speed at the air inlet of greenhouse was 1.9m.s$^{-1}$ . Since time controller sprayed amount of constant water at a given interval, some of sprayed water remained not to be evaporated, which increased relative humidity and decreased cooling efficiency. Because the shading screen prevented air flow in the greenhouse, it also caused the evaporation efficiency to be decreased. In order to increase cooling efficiency, it was necessary to study on controling by relative humidity and air circulation in the greenhouse.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.441-447
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• 2021

It were investigated changes in internal and external temperature, relative humidity using tyvek, weedstop, and 35% shading net as covering material to reduce the freezing damage of 'Shiranui' hybrid mandarin grown in open field. It were also evaluated canopy covering effect and LT₅₀ of leaves by covering material when it was cold at -2℃. In tyvek, temperature difference between inside and outside was low at the height of 1.5m and was high at 0.4m. The relative humidity differed greatly between day and night, and was high at 6-8 a.m. At -2℃, Sum of temperature at the height of 1.5m of canopy for 24-hour after covering were at 3.4℃ higher in tyvek than in control. The LT₅₀ of leaves was at 1.51℃ in tyvek, 1.33℃ in withstop, and 1.61℃ in 35% shading net lower than in control. Considering thermal insulation and relative humidity in canopy, tyvek is expected to reduce low temperature damage when covering after making a fine hole for ventilation.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.452-459
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• 2022

One of the important factors among the smart farm factors is environmental measurement. This study tried to design an environmental measurement monitoring system through Bluetooth wireless communication with LoRa using the open source programs Arduino, App Inventor, and Node Red. This system consists of Arduino, LoRa shield, temperature and humidity sensor (SHT10), and carbon dioxide sensor (K30). The environmental measurement system is configured as a system that allows the sensor to collect environmental data and transmit it to the user through wireless communication to conveniently monitor the farm environment. As libraries used in the Arduino program, LoRa.h, Sensirion.h, LiquidCrystal_I2C.h and K30_I2C.h were used. When receiving environmental data from the sensor at regular intervals, coding using average value was used for data stabilization. An Android-based app was developed using Node Red and App Inventor program as the user interface. It can be seen that the environmental data for the sensor is well collected with the screen output to the serial screen of Arduino, the screen of the smartphone, and the user interface of Node Red. Through these open source-based platforms and programs will be applied to various agricultural applications.

• Journal of Bio-Environment Control
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• v.8 no.2
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• pp.75-82
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• 1999

This study was carried out to examine the effect of day/nignt temperatures during seedling culture on the vegetative and reproductive growth of Lycopersicum esculentum ‘Seokwang’. The study was consisted of two culture stages, plug seedling production in the growth chamber and hydroponic culture of the plant in a glasshouse. Experiments were replicated over time. The germinated seedlings were raised for 33 days (experiment 1) and 35 days (experiment 2) in 4 growth chambers, each with day/night temperatures of either $25^{\circ}C$/$25^{\circ}C$, 16$^{\circ}C$/16$^{\circ}C$, 16$^{\circ}C$/$25^{\circ}C$ or $25^{\circ}C$/16$^{\circ}C$. Cool-white fluorescent lamps provided 140$\mu$mol.m$^{-2}$ .s$^{-1}$ light for 12h each day. In the second experiment, all chambers were supplied with 1000$\mu$mol.mol$^{-1}$ CO$_{2}$ during the photoperiod and had an air velocity of 0.3m.s$^{-1}$ and relative humidity of 80%. Plug seedlings raised were transplanted to rockwool slabs in a glasshouse and were grown hydroponically using the same nutrient solutions used for seedling culture for 37 days (experiment 1) and 35 days (experiment 2). Plant height was affected more by mean daily temperature than by interaction of day and night temperatures. Plant height was the highest in 16/16$^{\circ}C$ treatment. Leaf count was not affected by day and night temperatures, and the chlorophyll concentration was the highest in 16/$25^{\circ}C$ treatment. Fresh and dry weights of stem tended to be greater in treatments of constant day and night temperature. The number of node on which first and second flower clusters were set was significantly higher in 25/$25^{\circ}C$ treatment than in the other treatments. Days to flower of the first flower on the first flower cluster were the greatest in 25/$25^{\circ}C$ and the least in 16/$25^{\circ}C$ treatment. Vegetative and reproductive growth, such as height, fresh and dry weights, days to flower, and nodes of the 1st and 2nd flower cluster set were affected by day/night temperatures.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.341-348
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• 2013

Maintenance of adequate soil tension or content during the period of crop growth is necessary to support optimum plant growth and yields. A better understanding of soil tension and content for precision irrigation would allow optimal soil water condition to crops and minimize the adverse effects of water stress on crop growth and development. This research reports on a comparison of soil water tension and content variations in differently textured soils over time under drip irrigation using two different water management methods, i.e. pulse time and required water irrigation methods. The pulse time-based irrigation was performed by turning the solenoid valve on and off for preset times to allow the wetting front to disperse in root zone before additional water was applied. The required water estimation method was a new water control logic designed by Rural Development Administration that applies the amount of water required based on a conversion of the measured water tension into water content. The use of the pulse time irrigation method under drip irrigation at a high tension of -20 kPa and high temperatures over $30^{\circ}C$ was not successful at maintaining moisture tensions within an appropriate range of 5 kPa because the preset irrigation times used for water control could not compensate for the change in evapotranspiration during day and night. The response time and pattern of water contents for all of the tested soils measured with capacitance-based sensor probes were faster and more direct than those of water tensions measured with porous and ceramic cup-based tensiometers when water was applied, indicating water content would be a better control variable for automatic irrigation. The required water estimation-based irrigation method provided relatively stable control of moisture tension, even though somewhat lower tension values were obtained as compared to the target tension of -20 kPa, indicating that growers could expect to be effective in controlling low tensions ranging from -10 to -20 kPa with the required water estimation system.