• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.364-370
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• 2014

The nutrient and irrigation management of scion and rootstock can alleviate stress on grafted transplants after grafting and promote the growth. This study investigated the effects of nutrient and irrigation management of scion and rootstock on the graft-take and growth of grafted pepper transplants. Before grafting, the scions were subjected to different water potential regimes in media by controlling the irrigation frequency and time. The scions were subirrigated 0, 1(two days before grafting), 1(one days before grafting) or 2 times for five days before grafting. The irrigation frequency and time influenced the water potential of media and the growth of scion and grafted transplants. At 13 days after grafting, fresh and dry weight of transplants which were irrigated once at two days before grafting were greater by 29 and 34% than those without irrigation during five days before grafting. This suggests that mild water stress on scion prior to grafting by controlling water management alleviate water stress on grafted transplants after grafting and improve the growth. Before grafting, the rootstocks were subjected to different nutrient regimes by controlling nutrient solution application. The rootstocks were supplied with nutrient solution 0, 1, 2, or 4 times. The nutrient application frequency and time influenced the electrical conductivity (EC) and pH of media. Accordingly, the growth and mineral contents of rootstock and grafted transplants were also affected. At 13 days after grafting, fresh and dry weight of transplants with four times of nutrient application increased by 30 and 20%, respectively, than those without nutrient solution supply during seven days before grafting. Therefore, it is recommended that nutrient solution be supplied more than four times during seven days before grafting for the production of high quality transplants.

• Journal of Bio-Environment Control
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• v.26 no.1
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• pp.7-12
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• 2017

This experiment was conducted to analyze the effect of drainage reuse rate on the growth and fruiting of summer paprika in closed hydroponic cultivation. The experiment was carried out for 25 weeks from March to September 2015 with 0, 20, 30, 50% mixing ratio of waste nutrient solution using non - recycling hydroponic cultivation as a control. As a result, stem diameter of the test was different in the groups 1 and 2, but no difference showed as the group progressed more than 3 groups. L.A.I tended to decrease with increasing drainage mixing ratio. The number of nodes in the 50% reuse test group was 1.4 compared to the control group, but there was no significant difference. The number of harvested nodes was significantly different in the control group (11.1 nodes) and the 50% reuse test group (8.7 nodes), and the harvested nodes tended to decrease as the drainage was reused. The ratio of harvest was also the same as that of the harvesting node, and the control was the highest at 33.2% and the lowest at the 50% reuse test at 27.6%. Relative yields were reduced by 30%, 35% and 45% in the control group in the first group, and this tendency was also observed in the second and fourth groups. However, in the 3 and 5 groups, the production of 50% test group increased by 13% and 5%. The ratio of unmarketable fruit was increased 2%, 4%, 4%, and 7% in 0%, 20%, 30% and 50% reuse test, respectively. In conclusion, if the decrease in yield due to the decline in early growth is carefully managed, even if the imbalance of inorganic ions occurs after the mid-term growth, the growth of the crop will enter into a stable period and the re-use will not be worried about the growth and the yield decrease.

• Journal of Bio-Environment Control
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• v.26 no.1
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• pp.35-42
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• 2017

This research was conducted to investigate the influence of post-planting fertilizer concentrations on the growth of seedlings and changes of nutrient concentrations of media in tomato seedling production through sub-irrigation. Two root media such as peat moss (grade of 0 to 6 mm, PM06) plus perlite (grade of 1 to 2 mm (PE2)(7:3, v/v) and peat moss (grade of 5 to 15 mm, PM515) plus PE2 (7:3, v/v) were formulated and filled into 72-cell plug trays. After seeds of 'Dotaerang Dia' tomato were sown and germinated at $28^{\circ}C$, the trays were moved to greenhouse and seedlings were raised 35 days. When the cotyledons were emerged, post-planting fertilizers of 13-2-13, 15-0-15 and 20-9-20 ($N-P_2O_5-K_2O$) were applied in a sequence. The fertilizer concentrations based on N in each plug stage were differed with $25mg{\cdot}L^{-1}$ in three treatments. The fertilizer solutions were supplied when the weight of plug trays decreased to 40 to 50% compared to container capacity. The root media were collected in 1, 2, 4, and 5 weeks after sowing and were divided into top, middle, and bottom parts, then were analysed for pH, EC and macro-nutrient concentrations. The seedling growth was investigated 5 weeks after sowing. The pH and EC in PM06+PE2 was higher than those of PM515+PE2. The bottom and mid-part had higher pH and lower EC compared to upper part in each medium. The differences of EC between upper and bottom parts were around 2 times in each medium. The $NH_4-N$ and K concentrations in program 3 of PM06+PE2 showed the highest concentrations among all treatments. The $NO_3-N$ concentrations in PM06+PE2 increased gradually and this rising tendency become severe as post-planting fertilizer concentrations were elevated. The seedling growth in terms of fresh and dry weights was the highest in the treatment of program 2 in PM06+PE2 among all treatments tested. Above results indicate that the gradual increases of fertilizer concentrations from 25 to $125mg{\cdot}L^{-1}$ in plug stages 2, 3, and 4 plug stages are desirable for

• Journal of Bio-Environment Control
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• v.26 no.1
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• pp.43-48
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• 2017

This experiment was conducted to test the suitability of various organic materials in order to reduce the use dependence of peatmoss as a soil pH regulator and to examine the effect of soil organic matter supply. A 2-year old northern-highbush blueberry (Vaccinium corymbosum L.) 'Duke' plants were planted in the field at $2.0m{\times}2.5m$ spacing in spring. Before planting, organic materials were incorporated into the soil including the planting hole at 20 liter per plant, as the following mixtures: peatmoss only (20 L), peatmoss (10 L) + pine needle (10 L, PN), peatmoss (10 L) + rice hull (10 L, RH), and peatmoss (10 L) + sawdust (10 L, SD). The pH of organic materials was lowest in peatmoss (pH 4.3), followed by PN (pH 4.8), SD (pH 5.7) and RH (pH 7.8). Soil pH measured right after planting ranged from 5.3 to 5.9 and was lower in PM only and PM + PN than PM + RH and SD treatments. In the third year, the pH lowered to the range of 4.2 to 4.5, with PM and PM + PN still maintaining lower values. The early growth was good in the mixed treatment of PM and PN, and the plant height and width and the number of new shoots were good in the PM treatment. Soil water content was maintained highest in PM + PN, followed by PM, PM + SD and PM + RH. Vegetative growth was maintained better in PM and PM + PN, and the number of flower cluster and yield were also slightly higher in those treatments while mean fruit weight was similar among all treatments. Fruit quality indices such as total soluble solids, titratable acidity and firmness were not affected.

• Journal of Bio-Environment Control
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• v.24 no.4
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• pp.296-300
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• 2015

This study was conducted to investigate optimal crop loads of 'Jinok' grape for unheated plastic house culture. The crop loads of 'Jinok' grapes were managed to be 1.3, 1.8, 2.2, 2.4, and 2.6t per 10a from 2012 to 2014. We measured vine growth and berry qualities. Crop loads were not significantly affected on plant height, trunk diameter, shoot length, and the internode length of 'Jinok'. However, the maturation of berries was delayed when the crop load was higher. And the harvest date was earlier about three weeks in an unheated plastic house compared to in an open field. The average berry weight was decreased by the higher crop load although higher crop loads made higher yields showing the lowest weight at 342g with the treatment of 2.6t per 10a and the highest weight at 363g with the treatment of 1.3t per 10a. Also, the soluble solids content showed a tendency that higher crop loads brought to lower degree Brix. The contents of P, K, Ca, and Mg in grape leaves and shoots were not significantly different by crop loads. To sum up, when crop loads were under the 2.4t per 10a, the berries were harvested as a marketable fruit having $15^{\circ}Brix$ in the cultivar 'Jinok' grape. This result could help to increase grower's benefit having improved quality of fruit for the sustainable production by the established cultivation techniques for the newly developed cultivar 'Jinok'.

• Journal of Bio-Environment Control
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• v.24 no.4
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• pp.301-307
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• 2015

High quality transplants are critical for success in crop production. Increasing numbers of growers purchase their transplants from specialized transplant producers instead of growing their own transplants. A drawback of purchasing transplants is the risk of deterioration to transplants during transportation from transplant producers to the growers. This study evaluates the influence of temperature on the quality of grafted tomatoes transplants (Solanum lycopersicum cv. Super Doterang), in order to propose optimum temperature condition for the transportation of grafted tomato transplants. Grafted tomato transplants with visible flower trusses were exposed to different air temperature ($10^{\circ}C$, $25^{\circ}C$, or $40^{\circ}C$) for 2, 4, or 6 hours. After treatment, the NDVI (Normalized Difference Vegetation Index) values of tomato transplants treated at 25 and $40^{\circ}C$ were lower than that at $10^{\circ}C$. The root fresh weight was lowest at $40^{\circ}C$. After transplanting, the transplants that were exposed to the air temperature of $40^{\circ}C$ exhibited chlorosis and blight on lower leaves. The degree of damage on leaves was severer as the high temperature exposure time was longer. The temperature conditions during the transportation also influenced the growth, flowering and fruit set of tomatoes after transplanting. The fruit number and weight of first truss was lowest at $40^{\circ}C$ for 6 hours. Accordingly, it is recommended that the temperature during the transportation should be controlled and kept at the range from 10 to $25^{\circ}C$ even though the period is short (within as six hours) in order to maintain the quality of transplants.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.397-402
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• 2010

This study was conducted to find out the appropriate type and concentration of plant growth regulator for mass production of wild type Hydrangea serrata. And the optimal soaking time for rooting of the cuttings was also investigated. When the cuttings of Hydrangea serrata were cultivated for 6 weeks after immersing in $50mg{\cdot}L^{-1}$ of IBA for 3 hrs, the number of roots was 90.6. However the number was significantly decreased when the cuttings were treated with $10mg{\cdot}L^{-1}$ of IBA. The rooting ratio was 100% when the cuttings was immersed in 1,000, 2000 and $3000mg{\cdot}L^{-1}$ of NAA solution for 5, 3 and 10 sec., respectively. Despite the perfect rooting, the number of roots was decreased. The number of roots was 105.5 when the cuttings were treated in $2,000\;mg{\cdot}L^{-1}$ of NAA for 5 sec., which was the highest number in NAA treatment. Overall, the rooting ratio and growth was better when the cutting was treated with low concentration of IBA ($50{\sim}250\;mg{\cdot}L^{-1}$) than the treatment of NAA. And the most appropriate concentration and time fot the treatment of IBA was $50mg{\cdot}L^{-1}$ and 3 hrs, respectively.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.116-123
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• 2008

This study was carried out to investigate into the effect of light-emitting diode (LED) for the light quality as a light source on the broccoli seed germination and the physiological activity of vegetable sprouts. We have also germinated seeds of the broccoli and applied LED as a light quality such as blue, green, red, white, yellow and red + blue color lights to their sprouts for 14 hours and kept dark for 10 hours at the temperature of $25^{\circ}C$ (day)/$18^{\circ}C$ (night). Broccoli sprouts were extracted by methanol and their physiological activities were examined. All broccoli seeds were germinated at 3 days after seeding regardless of the light color. Total sprout fresh weight were mostly became highest by 0.389g (10 plants) at 8 days after seeding when their sprouts were grown under blue color light. Total phenol compound contents in broccoli sprouts were extremely increased by $83.0\;mg{\cdot}L^{-1}$ under the white light, and total flavonoid contents were most much more by $72.6\;mg{\cdot}L^{-1}$ under the blue light. DPPH radical scavenging activity at $2,000\;mg{\cdot}L^{-1}$ were most highest by 93.5% in broccoli sprouts grown under the white light. Nitrite radical scavenging activity at the concentration of $500\;mg{\cdot}L^{-1}$ in sprout extracts were the most increased by 66.9% under the yellow light, and tyrosinase inhibition activity at $2,000\;mg{\cdot}L^{-1}$ in sprout extracts were by 14.5% under red light.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.249-254
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• 2016

This study was carried out to evaluate the efficiency of white shading agent for reduction of greenhouse air temperature and to develop cost-effective cooling strategies for strawberry seedling production during hot seasons. Experiment results showed that solar radiation ($W/m^2$) was reduced by 14~17% and 33~37% for 15% and 35% white wash shading treatments, respectively, in black shading net treatment solar radiation was reduced by 39~44% compared to non-shaded treatment. Measured greenhouse air temperatures in 15% and 35% white wash shading treatments were $38.4^{\circ}C$ and $36.5^{\circ}C$, respectively, whereas in black shading net covered greenhouses air temperature was $35.1^{\circ}C$, thereby 35% and 15% shading treatments showed 3.3 and $1.9^{\circ}C$ higher air temperatures than black net shading treatment. Crown diameter of strawberry plants in black net shading treatment was 7.5mm, and in 15% and 35% white wash shading treatments were 8.6mm and 8.3mm, respectively. Strawberry transplants grown in 35% white wash shading treatment produced the highest above ground fresh weight(7.8g), followed by 15% white wash shading(6.7g) and black net shading treatments(5.8g). Also, both 15% and 35% white wash shading treatments produced higher root fresh weight(4.1g and 4.3g) compare to black net shading treatments(2.7g).

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.334-342
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• 2016

In order to evaluate the modified installation methods of roof ventilation devices, derived from the previous experiment ('investigation into the optimum capacity of roof ventilation devices and their deployment'), the conventional and modified (improved) roof ventilation systems were installed in the single-span plastic greenhouse for growing oriental melons. The roof vents ($60{\varphi}$) and roof fans (maximum air capacity of $38m^3/min$) were installed in the spacing of 15m (FT, modified 'side vent+roof fan' ventilation) and 6m (TT, modified 'side vent+roof vent' ventilation) respectively on the roof of greenhouses for the modified roof ventilation treatments, and 20m (FC, conventional 'side vent+roof fan' ventilation) and 8m (TC, conventional 'side vent+roof vent' ventilation) for the conventional ones. The stem diameter, leaf blade lengh, petiole length, and leaf width were lower in the FT and TT treatments than those in the conventional treatments, FC and TC. Although the fruit weight and total yields were slightly lower in the FT and TT treatments, the marketable fruit ratio (%) were higher, as a result of increased fruiting ratio (%) in these treatments, than those of FC and TC. The marketable yields (kg/10a) in the FT and TT treatments were 8,391 kg/10a and 7,283 kg/10a, which were respectively 661 kg/10a and 487 kg/10a higher than those in the treatments of FC and TC. The modified installation methods of roof fan resulted in production of more female flowers and lower fruit drop ratio (%) compared to conventional meathods. In the treatment of the conventional ventilation with roof vent, the fruit weight, fruit length & width, and flesh thickness were higher than in other treatments, but there were no significant differences in the fruit width and flesh thickness among the treatments.