• Journal of Bio-Environment Control
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• v.25 no.1
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• pp.63-70
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• 2016

Water drainage from the open hydroponics often causes significant environmental pollution due to agrochemicals and loss of water and nutrients. The objectives of this study were to show the potential application of an irrigation schedule based on threshold values of volumetric substrate water content for tomato (Solanum lycopersicum L. 'Samsamgu') cultivation in a commercial hydroponic farm during spring to summer cultivation. This study was performed for minimizing effluent from coir substrate hydroponics using a frequency domain reflectometry (FDR) sensor-automated irrigation, as compared with an integrated solar-radiation (IR) and conventional timer-irrigation (TIMER) after transplanting. In results, no significant difference in daily irrigation volume was found among the treatments until 88 days after transplant (DAT). However, during the 88 to 107 DAT, the daily irrigation volume was in the order of IR (2125 mL) > TIMER (2063 mL) > FDR (1983 mL), and during the 108 to 120 DAT, it was in the order of IR (2000 mL) > TIMER (1664 mL) > FDR (1500 mL). The lowest drainage volume was observed in the FDR treatment with the order of IR (12~19%) > TIMER (4~12%) > FDR (0~7%) during the entire growing period. A lower irrigation volume in the FDR treatment after 88 DAT may be due to the sensor's detecting capacity for less water absorption by plant after completing fruit maturity with apical pruning and removal of lower leaves, while a higher irrigation volume in the IR treatment may be due to gradual increase in integrated solar-radiation amount as closer to summer season. There was no significant difference in plant growth and fruit yield among the treatments; however, a 11% and 18% of higher soluble sugar content was observed in the FDR than that of TIMER and IR treatment. respectively.

• Journal of Bio-Environment Control
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• v.26 no.2
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• pp.100-107
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• 2017

This experiment was carried out to analyze the effects of substrate reuse on the growth and yield of summer paprika in cyclic hydroponics. The test group was divided into a new coco slab, one year reused coco slab two year reused coco slab based on 30% nutrient solution reuse, and was performed from April 18 to November 31, 2016 for 30 weeks. As a result, plant height of early growth was that the 2 year reused slab was longer than the new slab but the final growth period was 56.58 cm shorter. First group flower position was that reused slab was shorter by 2.92 cm than the new slab and the second group flower position was 0.31 cm long. The relative internode length of early growth, when the reused slab was used, the imbalance in the late growth stage was increased compared with the use of the new slab. The number of growth nodes in the 1 and 2 year reused slab was the smallest with 27.4 nodes. However, the number of harvested nodes did not show the difference in the test group, and the ratio of harvested that the 2 year reused slab was the highest at 26.8%. The ratio of unmarketable fruit tended to increase as the growth progressed. Fresh weight was 227.7g for new slab, 219.2g for 2 year reused slab and 21.2g for 1 year reused slab. The dry weight of the new slab increased with the reuse of the slab. It was 17.13g for new slab, 18.26g for 1 year reused, and 19.28g for 2 year reused. The average water content of the entire growth period was smaller as the slab was reused, and the 1 year reused slab was about 20g less than the 2 year reused slab. This trend was steadily occurring throughout the entire growing season. Especially, the reused slab for 1 year was less than 60g after 3 groups compared to other test groups. In conclusion, If will control seriously occurrence of unmarketable fruits by weakening after medium growth in summer-cultivated paprika in EC-based recycling hydroponic cultivation with reused cocopeat substrate, It is not what I have to worry that decrease of the yield and deterioration of the quality due to the change of physical and chemical properties of the slab and the pathogenic bacteria infection.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.465-472
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• 2011

To investigate the effect of inorganic ($GeO_2$) and organic (Ge-132) germanium treatment on Brasica juncea C. plant, growth characteristics and Ge contents were examined with various inorganic or organic germanium treatments (0, 5, 10, 25, 50, 75 and $100mg\;L^{-1}$), respectively. Brasica juncea C. growth did not much inhibited until Ge $10mg\;L^{-1}$ concentration under both Ge-132 and $GeO_2$ treatments as compared to control. On the other hand, at Ge concentration higher than $25mg\;L^{-1}$ concentration, Brasica juncea C. growth was inhibited under both Ge-132 and $GeO_2$ treatments. Under treatment of $GeO_2$, length of root and shoot slightly increased until $5mg\;L^{-1}$ concentration and dry weight slightly increased until $10mg\;L^{-1}$ concentration. Under treatment of Ge-132, length of root and shoot slightly increased until $10mg\;L^{-1}$ concentration and dry weight slightly increased until $25mg\;L^{-1}$ concentration. Total Ge contents in Brasica juncea C. early seedlings with $GeO_2$ treatment were a bit higher than those with Ge-132 treatment. Germanium was primarily accumulated in the roots (77%) with organic Ge (Ge-132) treatments, whereas Ge was primarily accumulated in the leaf (70%, respectively) with $GeO_2$ treatments. The Ge uptake rates in inorganic Ge treatments were slightly high than those in organic Ge treatments. Under inorganic Ge treatment with $2.5mg\;L^{-1}$, about 3% of Ge was accumulated into plant and distribution in leaf and root was 84.8% and 15.2%, respectively. Under organic Ge treatment with $2.5mg\;L^{-1}$, about 2.6% of Ge was accumulated into plant and distribution in leaf and root was 66.4% and 33.6%, respectively.

• Journal of Wetlands Research
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• v.23 no.4
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• pp.352-363
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• 2021

The purpose of this study was to evaluate the load of nutrients contained in the drainage discharged from the facility horticultural complex and to use them for re-use of fluids and design for introduction of water treatment plants. Representative hydroponic cultivation crops were selected as tomato, paprika, cucumber, and strawberry, and the total number of samples analyzed for water quality was 80. As a result of the analysis, since various fertilizer components such as N, P, K⁺, Na⁺, Mg²⁺, Ca²⁺, Si₄⁺, HCO₃^-, Cl^-, S^2-, Fe, Mn, Cu, Zn, Mo and B are contained at very high concentrations in the drainage, the need for water treatment was confirmed. Through statistical analysis, it was analyzed that the drainage concentration of strawberries was lower than that of tomatoes, paprika, and cucumbers. In the case of tomatoes, these essential ion concentrations are the highest, so it was confirmed that they are subject to valuable resources in terms of reuse of fertilizers. The load of N and P of the drainage discharged from the facility horticultural complex 1m² was analyzed. For N, the daily processing capacity of 4.0 kg of tomatoes, 3.3 kg of paprika, 3.0 kg of cucumbers, and 1.5 kg of strawberries was calculated based on 1 ha. It was suggested that the P concentration needs a scale and capacity that can handle 0.5 kg of tomatoes, 0.6 kg of paprika, 0.4 kg of cucumber, and 0.2 kg of strawberries per day. Through this study, the amount of nitrogen and phosphorus contained in the drainage discharged from the greenhouse of each crop was evaluated to analyze the economy. In addition, it was expected to be used as basic data that can be used to calculate the treatment capacity to be reflected when introducing water treatment facilities in facility horticultural complexes for sustainable agriculture.

• Journal of Practical Agriculture & Fisheries Research
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• v.24 no.4
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• pp.11-17
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• 2022

Ginseng hydroponic cultivation was cultivated as a nutrient solution and the growth was investigated 60 days later. The length(cm) increased from EC1.0 and EC2.0 concentrations to 5.47cm before, followed by EC0.5, 2.5, 1.5, and 0.0. The weight(g) increased from EC1.0 concentration to 2.39g before, followed by EC1.5, 2.5, 0.5, 0.0 and 2.0. The width(mm) increased from EC1.0 concentration to 1.9mm than before, followed by EC2.5, 0.5, 1.5, 2.0, and 0.0. In the ginseng growth experiment according to nutritional components, the average length of NO₃-N mixed experiment increased to 0.33cm, the average weight of 0.04g, and the average width of 0.35mm. In the experiment in which NH₄-N was mixed without NO₃-N, the growth was reduced to 0.37cm in average length, 0.03g in average weight, and 0.22mm in average width. In an experiment in which germanium(Ge) is mixed with a nutrient component, the average length is increased to 0.33cm, the average weight is increased to 0.04g, and the average width is increased to 0.35mm, but in an experiment excluding germanium(Ge), the growth is reduced to 0.11cm, the average weight is 0.04g, and the average width is 0.03mm.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.255-263
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• 2020

In this study, we evaluated the salinity tolerance of five forage rice cultivars (Mogwoo, Mogyang, Miwoo, Jowoo, and Yeongwoo) with respect to germination, seedling growth, productivity, and feed values in a reclaimed paddy field in Muan, Korea. We found that the cultivars Mogwoo, Miwoo, Jowoo, and Yeongwoo showed normal germination and seedling growth, even at saline concentrations of between 0.1% and 0.5%, whereas in contrast, there were significant reductions in the germination and seedling growth of Mokyang with an increase in salt concentration. Among the five cultivars assessed, the seedling growth of Mogwoo and Yeongwoo was relatively higher at different salt concentrations in hydroponic and sand cultivation. Furthermore, cultivation of the five cultivars in the reclaimed paddy field with an initial salt concentration of 0.3% revealed that Yeongwoo was relatively superior in terms of yield and feed value. In conclusion, the germination and early growth of Yeongwoo were relatively good at high salt concentrations, and the yield and forage value of this cultivar in a reclaimed paddy field were also relatively superior to those of the other assessed varieties.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.284-291
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• 1997

This study was conducted to evaluate the optimum hydroponic system and nutrient solution for shortening the early growth period and quality improvement of dendrobium ( Dendrobium Phalaenopsis) seedlings. Dendrobium seedlings with 3 to 4 leaves were transplanted in the deep flow technique(DFT) system, aeroponic system, and ebb and flow system with different concentration of balanced nutrient solutions recommended by the Japanese Horticultural Experiment Station. Growth characteristics of shoot and root were recorded and evaulated among treatments. For autumn cultivation, plant height was the longest at the DFT system with quarter concentration of nutrient solution, where aeroponic system with half concentration of nutrient solution. Aeroponic system stimulated the root growth but fresh weight was observed in the plots of DFT system. For spring cultivation, pH values increased up 7.5 at the DFT and aeroponic system, where EC values did not fluctuate regardless of cultural system. Ebb and flow system showed the best result in the growth of plant followed by BFT system and aeroponic system. Higher concentration of nutrient solution within this range of treatment was recommended for the growth promotion of leaf length and width in DFT system. In conclusion, growth responses differed depending on the cultural system, concentrations of nutrient solutions and duration of cltivation.

• Research in Plant Disease
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• v.11 no.2
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• pp.179-184
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• 2005

A previous study reported that the stem and root rot of paprika (Capsicum annum L. var, grossum) caused by Nectria haematococca became a threat to safe cultivation of the plant in the country. However, no strategies for control the disease have been suggested. In this study, fungicides registered for pepper were screened to evaluate their control effects on the disease. Among fungicides tested, prochloraz manganase complex com pletely suppressed mycelial growth of the pathogen at 10 ppm a.i. tebuconazole, benomyl, and carbendazim $\cdot$kasugamycin also effectively inhibited mycelial growth of the fungus. However, kresoxim-methyl and triflox ystrobin did not suppress mycelial growth but significantly suppressed conidial germination of the fungus. Azoxystrobin, benomyl, prochloraz, tebuconazol, and carbendazim$\cdot$ kasugamycin were also effective to retard conidial germination. In vivo tests, tebuconazole strongly inhibited the plant growth even at 16,000x (15.6 ppm a.i.), while others did not induce chemical injury at 4,000x or 8,000x when drenched into a rockwool cube. In a greenhouse test, prochloraz manganase complex at 125 ppm a.i. (4,000x) showed highest control value by $89.9\%$. Other fungicides thiophanate-methylthiram, axozystrobin, trifloxystrobin, and benomyl presented $60-80\%$ control value in the hydroponic cultivation system. However, application time and interval remained to be investigated for identify maximum residue limit.

• Horticultural Science & Technology
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• v.17 no.6
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• pp.737-741
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• 1999

We surveyed the physiological disorders of fruit vegetables grown in the greenhouse in Kyungbuk province in 1998. Greenhouses used for cultivation were mostly single or multi-span iron pipe houses covered with polyethylene film. Single span greenhouses were used for strawberry, oriental melon and watermelon. Fifty six percent of the surveyed farms was a mono-cropping system for oriental melon and tomato. There were greenhouses used for successive cultivation for 10 years or more for strawberry and oriental melon in Koryeong and Seongju. Varieties of fruit vegetables cultivated were diverse, especially in cucumber and watermelon. In strawberry, malformed fruits were observed most frequently in March and the small fruits at late harvest period. Leaf chlorosis, stunt plants and runner outbreak were also found during the growing season. In tomato, occurrence of malformed fruits was severe from March to May, and occurrence of cracked fruits and blossom- end rot was also severe in October and November. The self topping and abnormal stem in tomato were problem in hydroponic cultures in August and November, respectively. Malformed cucumber fruits, such as curved, club shaped, irregular shaped and narrow necked, occurred at late season. Umbrella-shaped leaf in cucumber in summer were caused by calcium deficiency. Most serious disorders were fermented and malformed fruits occurring from March to May in oriental melon, and cracked fruits occurring from April to May in watermelon. At late growing stage of melons the leaf chlorosis occurred with complex symptoms of leaf disease. Growers had little knowledge on physiological disorders, and also on diagnose and measures to cure the disorders. Most growers pointed out that poor soil environment and temperature management in the greenhouse as the main causes of physiological disorders.

• Journal of Bio-Environment Control
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• v.19 no.3
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• pp.123-129
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• 2010

A study on modeling of medium temperature drops of the elevated-bench hydroponic system for strawberry cultivation during low temperature season was conducted. Four different conditions were used for the experiment. These consisted of two kinds of bed types (plant, V), four kinds of medium (rice, perlite, rice hulls80% and peatmoss20%, perlite80% and peatmoss20%), two kinds of mulched bed (mulched, non mulched) and four kinds of greenhouse air temperature (l.5, 3.2, 5.0, $6.7^{\circ}C$), and the results were summarized as follows: Temperature drop of medium in the V-bed was slower than that in the plant bed, showing better insulation effect of V-bed. Temperature drop of medium with mulching on the top of the bed was slower than the case without mulching, as a result, the beneficial effect of temperature drop was appeared in mulched bed. Linear regression of the temperature descent rate and the temperature difference between medium and air showed significant correlation. The regression equation for the Pearlite80% and Peatmoss20% in the V-bed was f(x) = -0.2656 + 0.1345x at the $R^2$ of 0.9269. Using the model, the temperature drop during night can be predicted for the various media at the different depths.