• Journal of Bio-Environment Control
• /
• v.12 no.2
• /
• pp.89-94
• /
• 2003

This study was conducted to identify the effect of recycling method of drained solution on the concentration of drained solution, and growth and yield of tomato in the recycling system. The recycling methods of drained solution were composed of control, MEC (measurement of EC) and ANS (analysis of nutrient solution). The plant height in the early growth stage was not different among the treatments, but plant fresh weight and dry weight were higher in the MEC or the ANS than in the control. The growth including fruit number, fruit weight, and yield of tomato in the ANS as compared with the control was favorable. The EC of drained solution tended to decrease in the early growth stage, but that of drained solution increased in the late growth stage. It was low in the MEC and the ANS as compared with the control. The pH of drained solution was maintained by 6.2 to 6.5 throughout the growth period in the MEC and the ANS, but the pH of the control increased up to 7.2 at the late growth stage. The N and K concentrations of drained solution tended to decrease in the early growth stage, while those of P, Ca and Mg increased. In the late growth stage, concentrations of N, P, Ca and Mg tended to decrease, but that of K in the ANS was very low. Concentrations of N, P, K, Ca and Mg were lower in the MEC and the ANS than in the control.

• Journal of Bio-Environment Control
• /
• v.12 no.4
• /
• pp.195-199
• /
• 2003

In polyethylene film house treated with surfactants(SF316+FB0800), waterdrops attached on film surface were absorbed to filter paper of 9 cm in diameter and measured 1.21 mL in control, 0.15 mL in 1% and 0.07 mL in 2% on December 10 at 10:00, 2002. However, there was no clear difference between surfactant concentrations 1% and 2%, And the most waterdrop was measured at 10:00 in daytime. As the air temperature was higher in greenhouse, waterdrop was sweled. So, the least waterdrop was measured at 14:00. In greenhouse covered with surfactants concentrated 1% and 2%, transmittances of solar radiation were 9.3% and 12.9% higher than control, respectively. In air temperature and relative humidity, there were no significant difference in all greenhouse. in forenoon, the air temperature and relative surfactant treated film greenhouse tended 1~2$^{\circ}C$ warmer than that of control. However, sil temperatures of surfactant treated film greenhouse tended 3~4$^{\circ}C$ warmer than that of control. During winter, the lettuce growth in surfactant treated film greenhouse was faster than that of control. However, there was no difference between surfactant concentrations of 1% and 2%.

• Journal of Bio-Environment Control
• /
• v.15 no.4
• /
• pp.327-334
• /
• 2006

In tomato perlite bag culture, the available water content was analyzed for several sorts of perlite so that the irrigation safety was investigated and thus the irrigation strategy controlled by time clock was established. The reduction trends of water content in perlite bags were monitored for tomatoes, of which fruits were harvested until the fifth cluster. The amount of daily reduction of water in the bag was on the decrease as the total water in the bag was decreased. In terms of time interval from when the water content based on weight was reduced more than 50g to when it was dropped again, the longest time interval in a day was retarded gradually. It means plant activity was recovered later than the previous day. The available water content in perlite bag of 40 liters was about 30% which was 12 kg in weight, which satisfied daily water demand of 6 tomato plants. The appropriate time irrigated by time clock was recommended for the case that it was irrigated 5 or 10 times a day with the daily integrated solar radiation of 601 or $1,519W/m^2$.

• Journal of Bio-Environment Control
• /
• v.23 no.1
• /
• pp.50-55
• /
• 2014

This study was conducted to investigate the responses of red pepper (Hongjinju) leaves under water stress. Hyperspectral short wave infrared (SWIR, 1000~1800 nm) reflectance imaging techniques were used to acquire the spectral images for the red pepper leaves with and without water stress. The acquired spectral data were analyzed with a multivariate analysis method of ANOVA (analysis of variance). The ANOVA model suggested that 1449 nm wavebands was the most effective to determine the stress responses of the red pepper leaves exposed to the water deficiency. The waveband of 1449 nm was closely related to the water absorption band. The processed spectral image of 1449 nm could separate the non-stress, moderate stress (-20 kPa), and severe stress (-50 kPa) groups of red pepper leaves distinctively. Results demonstrated that hyperspectral imaging technique can be applied to monitoring the stress responses of red pepper leaves which are an indicator of physiological and biochemical changes under water deficiency.

• Journal of Bio-Environment Control
• /
• v.26 no.1
• /
• pp.27-34
• /
• 2017

This study was carried out to estimate structural stabilities in respect of ground footings of plastic greenhouses on reclaimed lands. A 6m-wide multi-span plastic greenhouse with steel spiral piles as well as two 8.2m-wide single-span greenhouses with steel spiral piles and continuous pipe foundation respectively were built up on a reclaimed land with a SPT N-Value of 2 and measured how much the greenhouses were lifted up and subsided. In addition, the uplift capacity of three kinds of spiral piles(${\phi}50$, ${\phi}75$ and ${\phi}100$) was determined on a nearby reclaimed land. The results showed that the greenhouses with spiral piles had a slight vertical displacement like moving up and down but the scales of the rising up and sinking were negligible when compared to that of the greenhouses. The vertical displacement of the multi-span greenhouse ranged from +9.0mm(uplift) to -11.5mm(subsidence). As for the single-span greenhouses with spiral piles and continuous pipe foundation, the measurements showed that it varied from +1.3mm to -7.7mm and from +0.9mm to -11.2mm, respectively. The allowable uplift capacity of spiral piles could all be determined under criteria of ultimate load and accordingly had a value of 0.40kN, 1.0kN and 2.5kN, respectively. It was not entirely certain enough to make a final judgement on structural stabilities in respect of ground footings, it appeared likely however that the greenhouses with steel spiral piles was tentatively observed without any problems on reclaimed lands within the period.

• Journal of Bio-Environment Control
• /
• v.24 no.4
• /
• pp.271-274
• /
• 2015

The objective of this study was to investigate the effects of composition of nutrient solution on the growth and quality of baby leaf vegetables (tat soi, romaine lettuce, beet, and red radish) hydroponically cultivated in plant factory. The seeds of four vegetable crops were sown in urethane sponges and cultivated for 14 days in a plant factory. Light intensity and photoperiod were $110{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and 16 h, respectively; and air temperature in photo/darkperiod was maintained at $25/20^{\circ}C$. Tap water was used for irrigation for 7 days after sowing, and then plants were irrigated for 7 days using tap water and the nutrient solutions of Korea Wonshi, Japan Enshi, and Yamazaki for lettuce. At 14 days after sowing, the fresh weight of tah soi was highest in the nutrient solution of Yamazaki for lettuce, and there were no significant differences among nutrient solutions in beet and red radish. When we compared leaf color using Hunter's a value, the nutrient solution of Korea Wonshi and Japan Enshi increased green color in baby leaf vegetables, while the nutrient solution of Yamazaki for lettuce increased red color. Total phenolic content of romaine lettuce was highest in the nutrient solution of Korea Wonshi, but tat soi, beet, and red radish showed no significant differences among nutrient solutions in total phenolic contents. From these results, we suggest that using the nutrient solution of Korea Wonshi can enhance the growth and quality of romaine lettuce and the nutrient solution of Yamazaki for lettuce is appropriate for enhancing the growth and red color of beet and red radish in plant factory.

• Journal of Bio-Environment Control
• /
• v.16 no.4
• /
• pp.291-296
• /
• 2007

This study was conducted to investigate the effects of horizontal air flow produced by circulation fans on horizontal and vertical profiles of meteorological factors. The three-dimensional distributions of air speed, air temperature, relative humidity and carbon dioxide $(CO_2)$ concentration were measured with and without the fans in operation. The uniformity of the spatial distribution of meteorological factors decreased as the outside air temperature decreased. In "fans off" condition, spatial variations of $4.7^{\circ}C$ in air temperature, 19% in relative humidity were detected. When the fans were operated, these variations were reduced to 2.2 and 6.3%, respectively. As the fan capacity increased, the difference in air temperature among sampling points decreased. The fan capacity of $0.0104m^3{\cdot}s^{-1}{\cdot}m^{-2}$ was enough to obtain a reasonable air flow in greenhouse. The vertical profiles of air temperature and $CO_2$ concentration were reasonably uniform regardless of measurement height and fan capacity. Further researches on the position of fans to reduce the difference in air temperature along the width and the effects of using a larger number of smaller fans are required.

• Journal of Bio-Environment Control
• /
• v.16 no.4
• /
• pp.379-387
• /
• 2007

This research was conducted to evaluate the influence of pre-planting fertilizer levels (PFL) and initiation time of fertigation (ITF) on growth and nutrient contents of tomato plug seedlings. The pre-planting fertilizer levels in a coir+peatmoss+perlite (4:4:2, v/v/v) substrate were adjusted to 0.5X, 1.0X and 1.0X, and initiation time of fertigation was set to 7, 14,21 and 28 days after sowing. Elevated PFL in same ITF increased plant growth such as fresh and dry weights at 35 and 70 days after sowing. Plugs with early feeding among treatments of equal amount of PFL also showed better growth as compared to those of later feeding. In each ITF, 0.5X treatment had the higher tissue $P_2O_5$ contents than 1.0X and 1.5X treatments. Elevated PFL resulted in the decrease of tissue K, Mg and Fe contents and increase of tissue Ca contents. The pH in soil solution of all root substrates except 0.5X treatment at 35 and 70 days after sowing were greater than 7.0, which is too high. This suggests that the amounts and kinds of Ca containing fertilizers should be altered to decrease the pH. The results of this research indicated that fertilizer levels should be increased to 1.5X except Ca fertilizer, and fertigation immediately after moving plug trays from germination room to greenhouse is required to increase crop growth and decrease cropping time.

• Journal of Bio-Environment Control
• /
• v.19 no.4
• /
• pp.189-194
• /
• 2010

A multi line electric tube consisted of XL pipes contained with 2~4 hot wires and water in it. The specification of one meter length multi-line electric tube was investigated and the proper number in the multi-line electric tube was determined. A multi line electric tube with three hot wires were found to be the most efficient for the media heating control system. Temperature rise of medium in the rice hulls media was faster than that in the perlite media, showed better insulation effect of rice hulls media. Temperature rise of medium with mulching on the top of the bed was faster than without mulching, resulted in the beneficial effect of temperature rise with mulching. The regression model for the rice hulls media with mulching air temperature of $5^{\circ}C$ were a = -0.1458 and b = -0.1088. Using the model, the temperature rise of medium during low temperature season can be predicted for the various media according to the different depths.

• Journal of Bio-Environment Control
• /
• v.19 no.4
• /
• pp.387-391
• /
• 2010

This research was conducted to get the basic information for improving production amount as well as fruit quality by using Prohaxadion-Calcium (Pro-Ca) used as 'Sato Nishiki', cherry cultivar, which is most frequently cultivated in Korea. In fruiting trees, we used Pro-ca and concentration of treatment selected 150, 200 and $250\;mg{\cdot}L^{-1}$. When treating Pro-Ca $200\;mg{\cdot}L^{-1}$, we could get the highest effect on inhibition of shoot growth. All treatments of Pro-Ca were increased chlorophyll a and b, respectively compared with control. Although treatments of Pro-Ca treatment showed the decreased effect on leaf area and there was no difference in fruit quality among treatments. Also, Pro-Ca $250\;mg{\cdot}L^{-1}$, sprayed 3 times, and pclobutrazol ($PP_{333}$) 500 and $1,000\;mg{\cdot}L^{-1}$, applicated soil, were treated to 1 year old plnted pot. Pro-Ca and $PP_{333}$ showed inhibition of shoot growth, especially, Pro-Ca showed the more effect than $pp_{333}$ on growth inhibition. Soil applications of $pp_{333}$ showed less effect to enlargement of tree trunk compared to Pro-Ca and control. Pro-Ca and $pp_{333}$ were not difference in number of inter-nodes when comparing to control, but they on decreased leaf area and increased chlorophyll.