• Korean Journal of Soil Science and Fertilizer
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• v.47 no.1
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• pp.23-27
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• 2014

Nutrient accumulation in surface soil has become a serious problem for cucumber production in greenhouse. However, still in many cases, soil management practices are only focused on maintaining crop yield, regardless of sustainability related with soil chemical properties. This study was conducted to propose a sustainable soil management practice by investigating the impact of cover crop species and nitrogen rate of fertigated solution on cucumber yield and soil chemical properties in greenhouse condition. Rye and hairy vetch were tested as a fallow cover crop, and each amount of urea (1/2, 3/4, 1 times of N fertilizer recommendations), determined by soil testing result, was supplied in fertigation plots as an additional nitrogen source. The result showed that the yield of cucumber was higher in rye treatment than control and hairy vetch treatment. In addition, rye effectively reduced EC and accumulated nutrients from the soil. Meanwhile, N concentration of fertigated solution showed no significant effect on the growth and yield of cucumber. Consequently, these results suggest that it is desirable to choose rye as a fallow catch crop for sustainable cucumber production in greenhouse.

• Horticultural Science & Technology
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• v.17 no.5
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• pp.581-583
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• 1999

This experiment was conducted to investigate the effects of uniconazole drench treatment on the growth and flowering of poinsettia and to suggest proper application dosage and time. Plant height, branch length, and leaf area were significantly restricted as the concentration of uniconazole increased. Application doses of 0.05 and 0.10 mg/pot effectively controlled the growth of poinsettia 'V-10 Amy'. Earlier soil drench of uniconazole resulted in more effective reduction in plant height, branch length, and leaf area. In all cases, no noticeable phytotoxicity by plant growth retardants tested was observed.

• The Journal of Korean Medicine
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• v.41 no.1
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• pp.93-106
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• 2020

Objectives: The aim of this review is to ascertain whether Bojungikgi-tang and its modifications is more effective than non-specific management in chronic fatigue syndrome (CFS). Methods: We collected clinical trials to investigate the effects of Bojungikgi-tang and non-specific management on general symptoms, fatigue, and sleep quality in CFS patients. The databases used for data retrieval were Pubmed, Central Cochrane, CNKI, VIP, CiNii, OASIS, RISS, and Koreamed. We performed selection/exclusion process from the found records according to prespecified criteria, and assessed the final included trials according to the Cochrane risk of bias tool. The included studies were classified on the basis of interventions in experimental group. Results: Seven randomized controlled trials (476 participants) were eligible and their results were synthesized in the meta-analysis. The synthesis showed a substantial effect of Bojungikgi-tang (relative risk 0.20 [95% CI 0.13 to 0.31], Z=7.44, P<0.00001; I²=0%) and combination of Bojungikgi-tang and Sosiho-tang (relative risk 0.15 [95% CI 0.08 to 0.28], Z=5.85, P<0.00001; I²=0%) compared with non-specific management on improvement of general symptoms. However, we could not find sufficient clinical research records to determine their effects of improvement on fatigue and sleep quality. Conclusions: Bojungikgi-tang and its modifications are more effective than non-specific management for improvement of general symptoms in CFS post-treatment.

• The Plant Pathology Journal
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• v.23 no.3
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• pp.180-186
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• 2007

The biocontrol agent, Serratia plymuthica A21-4, has been developed for controlling pepper Phytophthora blight. Serratia plymuthica A21-4 strongly inhibits the mycelial growth, zoospore formation, and cyst germination of Phytophthora capsici in vitro. The application of a cell suspension of strain A21-4 to pepper plants in pot experiments and in greenhouse successfully controlled the disease. The bacteria produced a potent antifungal substance which was a key factor in the suppression of Phytophthora capsici. The most active chemical com-pound was isolated and purified by antifungal activity-guided fractionation. The chemical structure was identified as a chlorinated macrolide $(C_{23}H_{31}O_8Cl)$ by spectroscopic (UV, IR, MS, and NMR) data, and was named macrocyclic lactone A21-4. The active compound significantly inhibited the formation of zoosporangia and zoospore and germination of cyst of P. capsici at concentrations lower than $0.0625{\mu}g/ml$. The effective concentrations of the macrocyclic lactone A21-4 for $ED_{50}$ of mycelial growth inhibition were $0.25{\mu}g/ml,\;0.25{\mu}g/ml,\;0.30{\mu}g/ml \;and\;0.75{\mu}g/ml$ against P. capsici, Pythium ultimum, Sclerotinia sclerotiorum and Botrytis cinerea, respectively.

• Journal of Bio-Environment Control
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• v.3 no.1
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• pp.66-71
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• 1994

In order to understand the mechanism of the wide occurrence of tipburn phenomenon in Chinese cabbage grown under protected cultivation, Chinese cabbage cultivated in two experimental plots was analyzed based on the distribution of some mineral elements by region in the plant and in the soil. The following results were obtained : 1) The occurrence of tipburn is not related to the concentration of Ca in the soil. 2) The concentration of Ca by region in the plant increased in the order such as inner leaf < middle leaf < outer leaf and inner vein < middle vein < outer vein. 3) From this results the cause of occurrence of tipburn phenomenon in Chinese cabbage which occurred at fixed times in the growth and development of the plant can be controlled by modifying environmental factors in order to prevent excessive transpiration in the inner leaf.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.353-360
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• 2017

In this study, the design and performance test of the air to water heat pump capable of producing hot water for greenhouse heating by using the surplus solar heat inside the greenhouse and the air heat outside greenhouse as the selective heat source were conducted. The heat storage operations using the surplus solar heat and the outside air heat were designed to be switched according to the setting temperature of the greenhouse in consideration of the optimum temperature range of the crop. In the developed system, it was possible to automatically control the switching of heat storage operation, heating and ventilation by setting 12 reference temperatures on the control panel. In the selective heat storage operation with the surplus solar heat and outside air heat, the temperature of thermal storage tank was controlled variably from $35^{\circ}C$ to $52^{\circ}C$ according to the heat storage rate and heating load. The heat storage operation times using the surplus solar heat and outside air heat were 23.1% and 30.7% of the experimental time respectively and the heat pump pause time was 46.2%. COP(coefficient of performance) of the heat pump of the heat storage operation using the surplus solar heat and outside air heat were 3.83 and 2.77 respectively and was 3.24 for whole selective heat storage operation. For the comparative experiment, the heat storage operation using the outside air heat only was performed under the condition that the temperature of the thermal storage tank was controlled constantly from 50 to $52^{\circ}C$, and COP was analyzed to be 2.33. As a result, it was confirmed that the COP of the heat storage operation using the surplus solar heat and outside air heat as selective heat source and the variable temperature control of the thermal storage tank was 39% higher than that of the general heat storage operation using the outside air heat only and the constant temperature control of the thermal storage tank.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.321-326
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• 2014

The aim of this study was to investigate which hydroponic system is the optimum for growth and photosynthetic characteristics of Angelica gigas during experiment. Angelica gigas 'Manchu' were sowed and managed under a growth room chamber. The environmental conditions (temperature $22^{\circ}C/18^{\circ}C$ (day/night), relative humidity 50-70%, photosynthetic photon flux density (PPFD) $120{\pm}6{\mu}mol\;m^{-2}s^{-1}$) were maintained for 3 weeks. Forty eight seedlings with 4-5 leaves were transplanted in deep flow technique (DFT), substrate, and spray culture systems [culture bed: 800 (L) ${\times}$ 800 (W) ${\times}$ 400 mm(H)] under $150{\pm}5{\mu}mol\;m^{-2}s^{-1}$ PPFD provided with fluorescence lamps and cultivated for 11 weeks. At the end of the experiment, fresh and dry weights, leaf lenghth and width, SPAD, root fresh, and dry weights, and root volume of Anglica gigas were measured. Photosynthetic rate of Anglica gigas were measured with portable photosynthesis systems to investigate optimum PPFD, $CO_2$ concentration, and air temperature conditions. Fresh and dry weights of Anglica gigas grown in substrate were significantly greater than DFT-treated, but there were not significant with spray treatment. Leaf photosynthesis of Anglica gigas showed the tendency to sharply increase as PPFD was increased from 50 to $200{\mu}mol\;m^{-2}s^{-1}$. Though $CO_2$ saturation point was around $1000-1200{\mu}mol\;mol^{-1}$, increase in air temperature from 16 to $26^{\circ}C$ did not quite affect photosynthesis of Anglica gigas. In conclusion, Anglica gigas may be optimally cultivated with a spray culture system as air temperature, PPFD, and $CO_2$ concentration for environment are controlled at $20{\pm}3^{\circ}C$, $150{\mu}mol\;m^{-2}s^{-1}$, and around $1000{\mu}mol\;mol^{-1}$ for mass production.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.158-166
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• 2017

The object of this study was to improve tomato seedling quality in low temperature(below 7, $10^{\circ}C$ during night time or daily mean air temperature was $18^{\circ}C$) by application of silicate fertilizer. Six different silicate fertilizer concentrations (8, 16, 32, 64, 128, and 256mM) or water as the control were applied to tomato seedlings twice a week for 20 days. Positive effects were observed in the growth parameters of the seedlings treated with 16 and 32mM silicate fertilizer; the most effective concentration of silicate at which seedlings showed the best performance was 16mM. However, a high concentration of silicate (256mM) caused negative effects on the growth. The transpiration rate decreased alongside with the increase of silicate concentration up to 32mM, possibly due to the increased stomatal diffusive resistance. Silicate stimulated the growth and development of tomato seedlings, resulting in increased growth parameters and root morphology. However, no significant differences were observed among treatment numbers of soil-drenching wuth the silicate (6, 10, or 20 times with 16mM) for 20 days, suggesting that silicate treatment with 6 times may be sufficient to induce the silicate effects. The application of 16mM of silicate fertilizer reduced relative ion leakage and chilling injury during low temperature storage. In addition, the seedlings treated with silicate fertilizer recovered faster than those without silicate treatment after low temperature storage.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.344-353
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• 2020

Plants native in Korea have not only ornamental values but also have excellent environmental adaptability, so they can be used as garden plants. Studies on proper volumetric water content (VWC) of substrates have been reported, but many have been conducted in glasshouse conditions where environmental factors were controlled. When considering garden planting, it is necessary to perform the automated irrigation system in outdoor conditions where rainfall occurs at frequent intervals. This research aimed to investigate the VWC suitable for the growth of Minuartia laricina, Arenaria juncea, and Corydalis speciosa in open filed. Sandy soil which consisted of particles of weathered rock was used, and the VWC of 0.15, 0.20, 0.25, and 0.30 ㎥·m^-3 was maintained using an automated irrigation system with capacitance soil moisture sensors and a data logger. No significant differences in growth and antioxidant enzymes activity of A. juncea were observed among VWC treatments. However, the survival rate was low at VWC 0.30 ㎥·m^-3 treatment, which was the highest soil moisture content. Even considering the efficiency of water use, we recommended that VWC 0.15-0.20 ㎥·m^-3 is suitable for the cultivation of A. juncea. Minuartia laricina showed better growth with lower VWC. Because of frequent rainfall in open field, plant volume and survival rate was high even in VWC 0.15 ㎥·m^-3 treatment. In C. speciosa, the plant height, number of shoots and lateral shoots, and fresh and dry weight were higher in plants grown in VWC 0.25 ㎥·m^-3 as compared with that in the plants grown at 0.15, 0.20, and 0.30 ㎥·m^-3. Based on these results, M. laricina needed less water in open filed, and A. juncea and C. speciosa required higher VWC, but excessive water should be avoided.

• Journal of Bio-Environment Control
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• v.15 no.2
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• pp.167-172
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• 2006

The objective of this study was to determine the effects of substrate water content and electrical conductivity (EC) on the incidence of brown fruit stem and blossom end rot in glasshouse sweet pepper (Capsicum annuum cv. Special). Three levels of water content and EC had been treated since the first fruit reached 3cm in diameter: that is, 49 (low), 65 (medium), and 86% (high) for water content, and 2.4 (low), 4.2 (medium) and $6.3dS{\cdot}m^{-1}$(high) for EC. Shoot growth was reduced with decreasing water content, and it was lower in both high and low EC treatments than medium EC treatment. Fruit weight at harvest was greater in both medium and hish water content treatments than low water content treatment (158g vs 146g). High EC reduced fruit weight compared to or low EC treatments. The incidence of brown fruit stem increased with increasing water content and with decreasing EC. The highest incidence was shown in the high water content/low EC treatment (38%), which was considerably higher than 2.4% of the low water content/high EC treatment. Blossom end rot occurred in general in the low water content and/or high EC conditions. These results indicated that substrate water content and EC should be controlled differently according to the growth stage, to reduce the incidence of blossom end rot and brown fruit stem in glasshouse sweet pepper. First, to reduce blossom end rot incidence, water content should be maintained high (86%) and EC low ($2.4dS{\cdot}m^{-1}$) until Sweets after fruit set. Secondly, to reduce brown fruit stem incidence, water content should be maintained low (49%) and EC high ($6.3dS{\cdot}m^{-1}$), especially after completion of fruit growth.