• Korean Journal of Environment and Ecology
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• v.31 no.3
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• pp.279-286
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• 2017

We investigated growth response and variation of ecological niche breadth of Hibiscus hamabo according to light, moisture and nutrient when global warming is proceeded by elevated $CO_2$ concentration and temperature. H. hamabo was cultivated in experimental condition in the greenhouse that are divided by control(ambient condition) and treatment(elevated $CO_2$ concentration and temperature). Light, moisture and nutrient gradients were treated within the control and the treatment. Although H. hamabo prefers higher light intensity(up to L3) to lowers', Hamabo mallow doesn't like excessive light intensity($787{\pm}77.76{\mu}mol\;m^{-2}s^{-1}$). Also, H. hamabo was difficult to grow in absent nutrient(0%) and excessive nutrient(20%). However, there was no trend with moisture gradients. The death rate of H. hamabo in the treatment was higher in all gradients except for the highest light intensity condition than control. It means that range of tolerance about light is narrowed when concentration of $CO_2$ gas and temperature is elevated. There was no trend of death rate according to moisture gradient, comparing between control and treatment. The death rate in all nutrient gradients within the treatment is lower than the controls'. It means that range of tolerance about nutrient is widened. The ecological niche breadth of H. hamabo in the treatment was narrower as 30.1% in light gradients but wider as 8.6% in moisture gradients and 30% in nutrient gradients than in the control. In the conclusion, when global warming is proceeded by elevated $CO_2$ concentration and temperature, growth of H. hamabo would be restricted by light intensity.

• Korean Journal of Environment and Ecology
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• v.34 no.4
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• pp.345-354
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• 2020

The purpose of this study was to investigate the effects of soil amendment treatments, such as hydroball, and active carbon, and planting Pennisetum alopecuroides for reducing calcium chloride (CaCl₂) of soil leachate and the growth of Pennisetum alopecuroides. The experiment planted Pennisetum alopecuroides in a plastic pot with a diameter of 10 cm and a height of 9 cm in a greenhouse April-October 2018. The experimental group comprised six treatments, including Non-treatment (Cont.), Hydroball (H), Active carbon (AC), planting Pennisetum alopecuroides (P), hydroball + planting Pennisetum alopecuroides (H + P), and active carbon + planting Pennisetum alopecuroides (AC + P). The dissolution of the CaCl₂ concentration 200ml of 10g/L was irrigated once every two weeks. We measured the growth (plant height, leaf length, leaf width, number of leaves), EC, pH, and exchangeable cations (K⁺, Ca²⁺, Na⁺, and Mg²⁺) according to the high concentration of CaCl₂ in the plant and soil leachate. In a treatment with the 'hydroball' amendment, the soil leachate electrical conductivity (EC), and the cation exchangeable were decreased more than those of the control, while the growth of Pennisetum alopecuroides relative growth rate(RGR) increased. Overall, application with the hydroball amendment added the planting of Pennisetum alopecuroides improved the salt reduction effect more than the control group. These results indicate that the application of the soil amendment agent hydroball was suitable soil amendments in accordance with the high concentration of calcium chloride (CaCl₂). Also, Planting Pennisetum alopecuroides is expected to be appropriate for salt-tolerant plant for soil affected by deicing salt agents.

• Journal of Bio-Environment Control
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• v.14 no.1
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• pp.22-28
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• 2005

The use of blankets to preserve heat in oriental melon cultivation is a common practise without artificial heating and warming systems. Efficiency of blanket decreased with annually usage. This experiment was conducted to investigate the effect of double layer nonwoven fabrics on heat conservation, plant growth, fruit quality and yield of oriental melon in greenhouse. The results were compared among the non-woven fabrics of 9+3, 6+6, 6+3 and 12 ounce from transplanting to April 20, 2001, 2002. Night temperature within tunnel was high at 9+3, 6+6, 6+3 and 12 ounce in order. In plant growth, stem length, leaf numbers and exudate, under double layer nonwoven fabrics were better than single layer blanket of 12 ounce especially, 9+3 double layer blanket was the best. Fruit weight, flesh thickness, soluble solid and marketable yield rate remained same in all treatments. Fermented fruit rate was the highest in 12 ounce as $32.9\%,\;19.6\%\;under\;9+3,\;17.1\%\;under\;6+6,\;16.6\%$ under 6+3 double layer nonwoven fabric, respectively. Compared to 2,260kg yield per 10a of 12 ounce single layer nonwoven fabrics, $7\%$ was increased under 9+3 but $3\%\;and\;13\%$ were decreased under 6+6 and 6+3 double layer nonwoven fabrics, respectively. Compared to income, 4,499-thousand-won per 10a, of 12 ounce single layer blanket, $13\%\;and\;3$ were increased under 9+3 and 6+6 double layer nonwoven fabrics, respectively. Whereas, $10\%$ decreased under 6+3 double layer nonwoven fabrics. From this results it is evident that 9+3 double layer nonwoven fabrics was the best for thermokeeping, fruit quality, and was most economic under non heating system.

• 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.1-6
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• 2017

The paprika has emerged as one of the highest-income crops by increase in dimestic and export demand in the greenhouse crops. Nevertheless, there is no standard for fertigation in soil, because general culture system is soilless culture. This study was conducted to establish the optimum nitrogen and potassium application level for paprika fertigation. Four different levels of nitrogen and potassium were applied, treatment levels were 0.5, 1.0, 1.5, 2.0 times of pimiento fertilization recommendations based on soil testing. Experiment to instigate the optimum amounts of nitrogen and potassium were carried out in 2012 and 2013, respectively13. Nitrogen application : stem diameter of 0.5 times was significantly lower than other treatments, but stem length was not affected by nitrogen fiertigation levels. Number of fruit and yield of first fruiting group harvest were not significant difference. but those of the second fruiting group were decreased by increasing nitrogen level beyond 1.0 times treatment and were the lowest in 0.5 times treatment. Overall, the optimum level of nitrogen for fertigation was judged 1.0 times of pimiento fertilization recommendations based on soil testing. Potassium application : Growth was no signigicant trend except stem length. Number of locule, fresh thickness and sugar content were not significant difference. Number of fruit and yield were not significant difference at the first and second fruiting group harvest. But those were significant difference at third fruiting group harvest, maximum yield was obtained by 1.5 times fertigation level. The optimum level of potassium for fertigation was judged 1.5 times of pimiento fertilization recommendations based on soil testing.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.266-274
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• 2010

This study aim to investigate fundamentally the growth and physiological responses of tomato plants in responses to two different levels of water deficit, a weak drought stress (-25 kPa) and a severe drought stress (-100 kPa) in soil. The two levels of water deficit were maintained using a micro-irrigation system consisted of soil sensors for the real-time monitoring of soil water content and irrigation modules in a greenhouse experiment. Soil water contents were fluctuated throughout the 30 days treatment period but differed between the two treatments with the average -47 kPa in -25 kPa set treatment and the -119 kPa in -100 kPa set treatment. There were significant differences in plant height between the two different soil water statuses in plant height without differences of the number of nodes. The plants grown in the severe water-deficit treatment had greater accumulation of biomass than the plants in the weak water-deficit treatment. The severe water-deficit treatment (-119 kPa) also induced greater leaf area and leaf dry weight of the plants than the weak water-deficit treatment did, even though there was no difference in leaf area per unit dry weight. These results of growth parameters tested in this study indicate that the severe drought could cause an adaptation of tomato plants to the drought stress with the enhancement of biomass and leaf expansion without changes of leaf thickness. Greater relative water content of leaves and lower osmotic potential of sap expressed from turgid leaves were recorded in the severe water deficit treatment than in the weak water deficit treatment. This finding also postulated physiological adaptation to be better water status under drought stress. The drought imposition affected significantly on photosynthesis, water use efficiency and stomatal conductance of tomato plants. The severe water-deficit treatment increased PSII activities and water use efficiency, but decreased stomatal conductance than the weak water-deficit treatment. However, there were no differences between the two treatments in total photosynthetic capacity. Finally, there were no differences in the number and biomass of fruits. These results suggested that tomato plants have an ability to make adaptation to water deficit conditions through changes in leaf morphology, osmotic potentials, and water use efficiency as well as PSII activity. These adaptation responses should be considered in the screening of drought tolerance of tomato plants.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.324-332
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• 2010

This experiment was carrid out to develop a culture method by sequential highland-lowland cultivation for year-round production of fresh leaves in Ligularia stenocephala. Rootstocks of Ligularia stenocephala cultivated in Daegwallyeong openfield were digged up on late October 2007 and then stored in $-2^{\circ}C$ refrigerator. The rootstocks were monthly transplanted in protected greenhouse in Gangneung from November 2007 to June 2008 for lowland cultivation, and also they were monthly transplanted in rainshelter in Daegwallyeong from June to August 2008 for highland cultivation. The early growth of Ligularia stenocephala transplanted on January 2008 was faster. Most plant of Ligularia stenocephala regardless of transplanting time of rootstock grew over 30cm at the time of first harvesting of leaves till May, while the yield decreased during the summer season. The average plant height of Ligularia stenocephala transplanted on July and August in Daegwallyeong highland was lower than that cultivated in Gangneung lowland during spring season. Using of rootstock stored made it possible to produce in highland from Apr. to Oct. during summer season, and also to produce in lowland from Nov. to May next year. Therefore, the results indicates that sequential highland-lowland cutivation by using of stored rootstock will be capable of yearround production of fresh leaves in Ligularia stenocephala.

• 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.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.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.317-323
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• 2017

In this study, the heating performance and the energy saving effect of the heat pump system using hot waste water(waste heat) of the thermal power plant discharged from a thermal power plant to the sea were analyzed. The greenhouse area was $5,280m^2$ and scale of the heat pump system was 120 RT(Refrigeration Ton), which was divided into 30 RT, 40 RT and 50 RT. The heat pump system consisted of the roll type heat exchangers, hot waste water transfer pipes, heat pumps(30, 40, 50 RT), a heat storage tank and fan coil units. The roll type heat exchangers was made of PE(Poly Ethylene) pipes in consideration of low cost and durability against corrosion, because hot waste water(sea water) is highly corrosive. And the heating period was 5 months from October to February. During the heating performance test(12 hours), the inlet water temperature of evaporator was changed from $32^{\circ}C$ to $26^{\circ}C$, and heat absorption of he evaporator was changed from 175 kW to 120 kW. The inlet water temperature of the condenser rose linearly from $15^{\circ}C$ to $50^{\circ}C$, and the heat release of condenser was reduced by 40 kW from 200 kW to 160 kW. And the power consumption of the heat pump system increased from 30 kW to 42 kW. When the inlet water temperature of condenser was $15^{\circ}C$, the heating COP(Coefficient Of Performance) was over 7.0. When it was $30^{\circ}C$, it dropped to 5.0, and when it was above $40^{\circ}C$, it decreased to less than 4.0. It was analyzed that the reduction of heating energy cost was 87% when compared to the duty free diesel that the carbon dioxide emission reduction effect was 62% by recycling the waste heat of the thermal power plant as a heat source of the heat pump system.