• Elastomers and Composites
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• v.35 no.3
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• pp.227-235
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• 2000

This study focused on the recycling technology and application of waste polyurethane scrap($5{\sim}7mm$) and waste urethane form from the footware scrap. Firstly we suggest the waste polyurethane can be used as a component of medium for hydroponic rose culture. Secondly, recycled thermoplastic polyurethane(RTPU) was produced and blended it with high impact polystyrene(HIPS). And also, in order to extend application of recycling field, the former was produced with adding the amine foaming agent to RTPU/HIPS alloy. The main purpose of this study is to diverse of the recycling of the waste polyurethane.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.103-111
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• 2019

Gray mold caused by Botrytis cinerea on strawberry plants is an economically significant disease in Korea. The rates for diseased fruits are high during the strawberry harvesting period from December to February, especially in hydroponic cultivation. This study assessed the effect of the nitrogen type in the soil culture and the electrical conductivity (EC) of the nutrient solution in a hydroponic culture on the gray mold incidence in 'Seolhyang' strawberry plants. The nitrogen sources assayed included calcium nitrate tetrahydrate (CN4), calcium nitrate decahydrate (CN10), ammonium sulfate (AS), and commercial fertilizer 213 (213). The effect of the EC was tested at 0.5, 0.8, 1.0, and $1.5dS{\cdot}m^{-1}$. The occurrence of gray mold varied according to the nitrogen type. The disease incidence and nitrogen content for the main nitrogen type were higher compared to the non-treated control. The AS treatment showed the highest occurrence of tipburn and gray mold. The incidence of gray mold as well as the nitrogen and phosphorus content of the leaves increased as the EC level was increased. These results indicate that the incidence of gray mold in strawberry plants is related to the nitrogen content of the leaf and the EC of the nutrient solution.

• Journal of Bio-Environment Control
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• v.16 no.1
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• pp.13-20
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• 2007

This study was conducted to collect the basic data fo the development ot hydroponic technique and the efficient promotion of water culture. We have also analysed the water culture associated domestic patent application informations searching for on-line internet site with an admission fee (http://www2.wips.co.kr) from the year 1983 to January, 2006. Fifty nine patent applications related to the hydroponics were searched for in this study. Main patent contents applied were as followed in the order of that nineteen applications about the hydroponic equipments by 32.2%, thirteen applications about the materials used in water culture by 22.0%, eleven applications about the composition of nutrient solution by 18.6%, nine applications about the cultural methods by 15.3%, and seven applications about the cultural media by 11.9%. The compositions of nutrient solution and the cultural methods intended for specific crops were increased in number following five applications about tomato plants and four applications about potatoes. Thirty three patents (55.9%) were mainly applied before the year 2000. Main patent contents were the compositions of nutrient solution before the year 2000 in contrast to the cultural methods and substrates after the year 2000.

• Korean Journal of Organic Agriculture
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• v.17 no.3
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• pp.357-370
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• 2009

This experiment was conducted to investigate the effects of compost leachate and concentrated slurry on growth of tomato in hydroponic culture. In process of composting, compost leachate was produced water was through a saturated compost heap. The concentrated slurry was produced by filtration and concentration by membrane process. Filtration of pig slurry was necessary to prevent the hose clogging in hydroponics culture. The treatments of this experiment were consisted of seven different liquid fertilizers; compost leachate(CL), concentrated pig slurry (CS), compost leachate+byproduct(CL+BP), concentrated pig slurry+byproduct(CS+BP), compost leachate 50%+nutrient solution50%(CL+NS), concentrated pig slurry 50%+nutrient solution50%(CS+NS) and nutrient solution(NS) for tomato based on nitrogen content. The chemical nutrient solution was the solution of National Horticulture Research Station for the growth of tomato. The concentration of nutrient solution was adjusted a range of $1.6{\sim}2.0 mS/cm$ in EC. 1. The compost leachate and concentrated pig slurry were low in phosphorus(P), calcium(Ca), magnesium(Mg), but rich in potassium(K). 2. Plant height, SPAD value of tomato was highest in the plot of CS+NS, intermediate in CL, CS+BP, and lowest in 100% concentrated pig slurry. 3. The tomato yield of compost leachate plot was 91% compared with inorganic nutrient solution. The compost leachate solution could be used as a nutrition solution of tomato in organic hydroponics. 4. The growth including plant height, SPAD value, fruit number, fruit weight and yield of tomato in the CL 50%+NS 50% was similar in the control. In conclusion, the mixture solution of 50% pig slurry and 50% nutrient solution could be used as a nutrition solution of tomato hydroponic culture.

• Korean Journal of Environmental Agriculture
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• v.37 no.4
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• pp.251-259
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• 2018

BACKGROUND: Various culture media have been used for hydroponic cultures of horticultural plants under the smart greenhouses with natural and artificial light types. Management of the culture medium for the control of medium amounts and/or necessary components absorbed by plants during the cultivation period is performed with ICT (Information and Communication Technology) and/or IoT (Internet of Things) in a smart farm system. This study was conducted to develop the cloud-based data analysis system for effective management of culture medium applying to hydroponic culture and plant growth in smart greenhouses. METHODS AND RESULTS: Conventional inorganic Yamazaki and organic media derived from agricultural byproducts such as a immature fruit, leaf, or stem were used for hydroponic culture media. Component changes of the solutions according to the growth stage were monitored and plant growth was observed. Red and green lettuce seedlings (Lactuca sativa L.) which developed 2~3 true leaves were considered as plant materials. The seedlings were hydroponically grown in the smart greenhouse with fluorescent and light-emitting diodes (LEDs) lights of $150{\mu}mol/m^2/s$ light intensity for 35 days. Growth data of the seedlings were classified and stored to develop the relational database in the virtual machine which was generated from an open stack cloud system on the base of growth parameter. Relation of the plant growth and nutrient absorption pattern of 9 inorganic components inside the media during the cultivation period was investigated. The stored data associated with component changes and growth parameters were visualized on the web through the web framework and Node JS. CONCLUSION: Time-series changes of inorganic components in the culture media were observed. The increases of the unfolded leaves or fresh weight of the seedlings were mainly dependent on the macroelements such as a $NO_3-N$, and affected by the different inorganic and organic media. Though the data analysis system was developed, actual measurement data were offered by using the user smart device, and analysis and comparison of the data were visualized graphically in time series based on the cloud database. Agricultural management in data visualization and/or plant growth can be implemented by the data analysis system under whole agricultural sites regardless of various culture environmental changes.

• Journal of Environmental Science International
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• v.26 no.9
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• pp.1081-1086
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• 2017

The present study was conducted for the purpose of analyzing the growth response of Dracaena braunii treated with chloride ions and to evaluate its salt tolerance. Distilled water (CON) was spiked with 1 (C1), 2 (C2), 5 (C5), 10 (C10) and 15 g/L (C15) $CaCl_2$, respectively. Acidity (pH) and electrical conductivity of hydroponic solution, and leaf width, leaf length, root length, number of leaves, fresh weight, dry weight and the water content of Dracaena braunii were measured. Acidity and electrical conductivity remarkably increased commensurate with increasing concentrations of $CaCl_2$. Growth in the C1 treatment was better than that in CON, whereas the C10 or C15 treatments caused either slow growth or withering of the plants. Fresh weight, dry weight and water content were significantly decreased in response to $CaCl_2$ concentration, compared with those in the control. These results showed that $CaCl_2$ concentration less than 1 g/L may be used as a hydroponic solution for D. braunii, as long as the water quality is not too saline. The chlorine ion has a negative effect on the growth.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.132-138
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• 2023

The Gymnocalycium mihanovichii has been an important export item of Korean flower industry for a long time. Although there is a high demand for grafted cactus from overseas, its production for export is limited. In this study, the growth and marketable yield characteristics of Gymnocalycium mihanovichii 'I-Hong' were compared between soil culture and ebb-and-flow hydroponic system with single- or double-tier bench. As a result, hydroponic methods with single-tier bench resulted in higher fresh weight and glove diameter compared to other cultivation methods. In the ebb-and-flow hydroponic system, hydroponic system with double-tier bench of grafted cactus traits has a lower growth rate than other cultivations. However, the hydroponic system with double-tier bench of grafted cactus significantly increased the yield. In conclusion, the yield from hydroponic system with double-tier bench was better than soil cultivation method. Although there were some differences in color depending on the cultivation method, it was considered that there was no difference in appearance of Gymnocalycium mihanovichii 'I-Hong'. Our results suggest the cultivation methods to overcome production constraints, expand their exports, and improve the value-added characteristics of grafted cactus.

• Journal of Animal Environmental Science
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• v.15 no.1
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• pp.51-58
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• 2009

The compost leachate was dark-colored solution that leaches out of the bottom of the compost pile. The compost leachate was rich in nutrients and can potentially used in plant culture. In the organic production, commercial liquid fertilizer was used to insure the availability of nutrients during the formation of the yield. The cost of supplemental liquid fertilizer could be reduced by developing a fertilizer based on animal fertilizer. This experiment was conducted to investigate the effect of different combination of compost leachate and conventional inorganic solution in hydroponic culture for lettuce growth. Six different treatments were applied. The compost leachate(CL) and nutrient solution(NS) were mixed by six different mixing ratios of 0:100, 20:80, 40:60, 60:40%, 80:20 and 100%:0% based on nitrogen content. The chemical nutrient solution was the solution of National Horticulture Research Station for the growth of leaf lettuce. The concentration of nutrient solution was adjusted 1.5 mS/cm in EC. The compost leachate was low in phosphorus(P), calcium(Ca), magnesium(Mg), but rich in potassium(K). The plant height of lettuce treated with CL 20+NS 80% was similar with 100% NS of control plot. Plant height was highest in the plot of CL 20+NS 80%. The treatment of 100% compost leachate was lowest in the growth characteristics of leaf lettuce. Number of leaf was very low in 100% compost leachate compared with plot of chemical nutrient solution. In the beginning of growth stage, SPAD value was reduced in plot treated with CL100%, but CL20+NS80% plot was higher compared to 100% compost leachate. SPAD value of leaf lettuce leaves was decreased as the amount of CL was increased. The dry weight of lettuce were 107.4, 104.2g in plot of NS 100% and CL 20%+NS80%, respectively. The leaf number and plant weight were decreased at high application plots of compost leachate. The leaf lettuce showed lowest in the plot treated with 100% compost leachate, and the growth of lettuce severely decreased after application of 100% CL treatment. The results showed that compost leachate can be use as liquid fertilizer for the organic hydroponic production. The mixture solution of 20% of compost leachate and 80% of nutrient solution could be used as a nutrition solution in hydroponic culture of leaf lettuce. Our studies have shown that is possible to produce using compost leachate, although growth is slower than when using a conventional inorganic hydroponic solution.

• Korean Journal of Medicinal Crop Science
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• v.20 no.4
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• pp.251-258
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• 2012

The management and control of mineral nutrients is one of most important techniques to increase the productivity and the quality of Korean ginseng. The mineral nutrients are measured with different plant tissues and different growth stages of 2-year-old ginseng grown under hydroponic culture with two different temperatures. The content of N, P, Ca, and Mg were higher at low temperature in both leaves and roots than those at high temperature. However, the content of K was high in leaves at low temperature compared to that of high temperature, while it was not significantly different in roots. The uptake amounts of N and K was higher throughout the experimental period at low temperature in both leaves and roots than those at high temperature. However, the uptake amount of P was not clearly different between two different temperatures and among six different growth stages. The uptake amount of N, P, K was generally decreased in leaves from June to August, while it was increased in roots. The relationship between dry weight and mineral nutrients in leaves was appeared positive with N, K, Ca, and Mg, but negative P. In roots, N, K, Ca, and Mg were negative, showing that was positive with only P. Comparing the correlation coefficients among mineral nutrients in leaves, N and K were significantly positive correlation each other. P was significantly positive correlation with Na and Zn. In case of roots, N was highly significant positive correlation with K, Mg, and Mn, but P was negatively correlated with Ca, Cu, Na, Fe, and Zn.

• Korean Journal of Plant Resources
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• v.19 no.2
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• pp.223-226
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• 2006

This study was conducted to select proper varieties of cucumber by comparing growth and yield in retarding cultivation under hydroponic culture. Number of leaves appeared to be the highest Chungjangoi and the lowest in Heukjinjuoi. Heukjinjuoi showed higher vegetative growth rate. Heukjinjuoi showed the highest number of female flowers while Chungjangoi the lowest. The ratio of female flower was the highest in Heukjinjuoi and the lowest in Chungjangoi. Abortion of female flower appeared to be the highest in Heukjinjuoi and the lowest with 0% in Chungjangoi. There was no significant difference in yield between treatments of removal and not-removal of lateral buds.