• Korean Journal of Organic Agriculture
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• v.18 no.1
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• pp.83-92
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• 2010

Organic farming is a type of agricultural practices based on naturally occurring processes excluding or strictly limiting the use of synthetic fertilizers, pesticides, and other chemicals. This study was conducted to investigate the influences of agro-based materials, effective microorganisms (EM), liquid silicate (LS), and organic liquid fertilizer (OLF) for water dropwort (Oenanthe stolonifera DC.) cultivation. Soil pH, soil organic matter, and plant available phosphorous decreased with LS application. Exchangeable Ca and Mg decreased with EM application, and electrical conductivity and exchangeable Ca and K decreased with OLF application. Most of essential nutrient contents in water dropwort were reduced with the treatments of LS, EM, and OLF as compared with those in control plot, except nitrogen and phosphorus. However, diseases and insect pests were almost not observed in the water dropwort in the agro-based material application plots, except cluster caterpillar (Spodoptera litura). Productivity of water dropwort tended to be reduced: its higher productivity in the OLF and EM+LS plots and lower in the LS and control plots.

• Korean Journal of Medicinal Crop Science
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• v.26 no.3
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• pp.240-247
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• 2018

Background: Saline soil has negative effects on the growth of most crops. Sodium is the main element that causes salt accumulation in soil. Organic materials such as cow and poultry manure, are frequently used during the preparation stage, which causes an increase in the rate of salt accumulation in the soil. Methods and Results: To investigate the influences of sodium on ginseng, $NaH_2PO_4$, $Na_2SO_4$, and NaCl were used to adjust the sodium concentrations at 0, 12.5, 25, 50, 75 and 100 mM in nutrient solution. In a 2-year-old ginseng, toxic symptoms appeared when the sodium treatment exceeded 50 mM. The sodium concentration in the leaves was 3.33%, which is more than twice as high as that of the control treated at 50 mM. As the sodium concentration increased, the root weight significantly decreased. In the 100 mM treatment, the weight decreased by 28% when compared to that of the control. The Amount of ginsenoside significantly increased with an increase in sodium concentrations. Conclusions: These results suggest that the growth of 2-year-old ginseng is negatively affected when sodium exceeds 50 mM. This result can be used for a as basis in diagnosing the physiological disorders of ginseng.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.298-301
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• 2005

Potato (Solamum tuberosum 'Dejima') plantlets were investigated on culture type and initial quantity of inoculation in bioreactor and survival rate by hydroponics for mass production. rode stems (1 to 1.5cm in length) of potato plantlets multiplied in vitro were grown for 3 weeks in liquid Murashige and Skoog (MS) medium with sucrose $30 g\; L^{-1}$. When plantlets (80-node inoculation) were raised in 10L balloon type bubble (BB) bioreactor, the healthiest growth of plantlets was obtained from explants cultured in ebb & flow culture with medium supplied periodically 12 times per day. The suitable inoculation quantity of 20L BB bioreactor was 120 pieces of stem segments (mean 2.2g fresh weight) in ebb & flow culture. Number of nodal shoot was eight on the average. In controlled culture room, survival rate of plantlets at 7 days after stem cutting was above $70\%$ when they were acclimatized by hydroponics grown in deep flow and solid medium culture. The highest survival rate of the stem cutting plantlets was in nutrient solution adjusted to EC $1.4dS{\cdot}m^{-1}$. Stem cutting plantlets through one culture could be obtained $670\~900$, when plantlets were grown in ebb & flow culture during 3 weeks using a 20L bioreactor with initial 120 pieces of nodal segments. 11 is possible In do mass production of seedlings cultured in bioreactor and hydroponics.

• Journal of Bio-Environment Control
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• v.12 no.1
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• pp.26-29
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• 2003

Experiments were conducted to estimate optimal potassium strength in the nutrient solution for ‘Nokgwang’and‘Kwari’green pepper seedlings cultured in small plug-cell trays. Plant height, stem diameter, and leaf area increased with increasing K concentration, with greater effect on ‘Kwari’ than ‘Nokgwang’. Total dry weight increased by increasing potassium strength.‘Kwari’had heavier dry weight than ‘Nokgwang’Chlorophyll content differed by cultivars and potassium strength. The highest chlorophyll content was obtained at 2.0 strength potassium in‘Nokgwang’, but not in‘Kwari’Net photosynthesis was greater in plants fertilized with 1.5 strength potassium for‘Nokgwang’and 2.0 strength potassium for ‘Kwari’than the other treatments.

• The Plant Pathology Journal
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• v.39 no.1
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• pp.123-135
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• 2023

Previously, Pseudomonas plecoglossicida YJR13 and Pseudomonas putida YJR92 from a sequential screening procedure were proven to effectively control Phytophthora blight caused by Phytophthora capsici. In this study, we further investigated the anti-oomycete activities of these strains against mycelial growth, zoospore germination, and germ tube elongation of P. capsici. We also investigated root colonization ability of the bacterial strains in square dishes, including cell motility (swimming and swarming motilities) and biofilm formation. Both strains significantly inhibited mycelial growth in liquid and solid V8 juice media and M9 minimal media, zoospore germination, and germ tube elongation compared with Bacillus vallismortis EXTN-1 (positive biocontrol strain), Sphingomonas aquatilis KU408 (negative biocontrol strain), and MgSO₄ solution (untreated control). In diluted (nutrient-deficient) V₈ juice broth, the tested strain populations were maintained at >10⁸ cells/ml, simultaneously providing mycelial inhibitory activity. Additionally, these strains colonized pepper roots at a 10⁶ cells/ml concentration for 7 days. The root colonization of the strains was supported by strong swimming and swarming activities, biofilm formation, and chemotactic activity towards exudate components (amino acids, organic acids, and sugars) of pepper roots. Collectively, these results suggest that strains YJR13 and YJR92 can effectively suppress Phytophthora blight of pepper through direct anti-oomycete activities against mycelial growth, zoospore germination and germ tube elongation. Bacterial colonization of pepper roots may be mediated by cell motility and biofilm formation together with chemotaxis to root exudates.

• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.193-201
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• 2013

This research was conducted to investigate the influence of compositions and concentrations of fertilizer solution on growth of lettuce as well as changes in chemical properties of root media. To achieve this three kinds of fertilizers such as acidic (AF), neutral (NF), and alkaline fertilizer (BF) were formulated and applied with the concentrations of 100 or $200mg{\cdot}L^{-1}$ based on nitrogen concentrations. The growth characteristics were investigated 10 weeks after transplant and the analysis of soil solution for chemical characteristics were conducted in every week. The BF was more effective than AF in crop growth of blue leaf lettuce 10 weeks after transplant and the treatment of BF200 showed the heaviest fresh and dry weights among all treatments tested. The treatment of BF also showed the highest growth followed by those of NF and AF in growth of red leaf lettuce, but the growth in treatments of $100mg{\cdot}L^{-1}$ were higher than those of $200mg{\cdot}L^{-1}$ in the three kinds of fertilizers. The differences among treatments in soil solution pH became larger from week 6. The pH in the treatment of $200mg{\cdot}L^{-1}$ was lower than that of $100mg{\cdot}L^{-1}$ when AF was applied, but the treatment of $200mg{\cdot}L^{-1}$ showed higher pH than that of $100mg{\cdot}L^{-1}$ in case of BF. The electrical conductivity of soil solution in treatments of $200mg{\cdot}L^{-1}$ were 0.2 to 0.4 unit higher than those of $100mg{\cdot}L^{-1}$ when those are measured as $dS{\cdot}m^{-1}$ in three kinds of fertilizers. The $NH_4$ concentrations were higher in the treatments of AF than those of BF, but the concentrations of Ca, Mg and $NO_3$ were vice verse. The concentrations of $PO_4^{-3}$ were the highest in the treatments of AF followed by those of NF and BF when three kinds of fertilizers were applied with equal nitrogen concentrations. The differences of nutrient concentrations in soil solution of root media were influenced by composition of fertigation solution and varied soil solution pH.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.371-380
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• 2018

Aim of this study was to investigate the effects of different nutrient solutions and various light qualities generated by LED on the growth and glucosinolates contents of watercress (Nasturtium officinale) grown under hydroponics for 3 weeks. The seeds of watercress were sown on crushed rockwool media and raised them for two weeks. They were transplanted in a semi-DFT (deep flow technique) hydroponics system. A controlled-environment room was maintained at $20{\pm}1^{\circ}C$ and $16{\pm}1^{\circ}C$ temperatures and $65{\pm}10%$ and $75{\pm}10%$ relative humidity (day and night, respectively), with a provided photosynthetic photon flux density (PPFD) of $180{\pm}10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and a photoperiod of 16/8h. To find out the best kinds of nutrient solutions for growing watercress, Otsuka House 1A (OTS), Horticultural Experiment Station in Korea (HES), and Netherland's Proefstaion voor Bloemisterij en Gasgroente (PBG) were adapted with initial EC of $1.0-1.3dS{\cdot}m^{-1}$ and pH of 6.2, irradiating PPFD with fluorescent lamps (Ex-1). Either monochromatic (W10 and R10) or mixed LEDs (R5B1, R3B1, R2B1G1, and W2B1G1) were irradiated with a differing ratio of each LED's PPFD to understanding light quality on the growth and glucosinolates contents of watercress (Ex-2). Although significant difference in the shoot growth of watercress was not found among three nutrient solutions treatments, but the root fresh weight increased by 13.7% and 55.1% in PBG and OTS compared to HES, respectively. OTS increased the gluconasturtiin content by 96% and 65% compared to PBG and HES. Compared with the white light (W10), the red light (R10) showed a 101.3% increase in the shoot length of watercress. Increasing blue light portion positively affected plant growth. The content of total glucosinolates in watercress was increased by 144.5% and 70% per unit dry weight in R3B1 treatment compared with R2B1G1 and W10 treatments, respectively. The growth and total glucosinolates contents of the watercress were highest under R3B1 among six light qualities.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.406-411
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• 2011

This study was conducted to find out the effect of cut-off period (0 hour, 3 hours, 6 hours, 12 hours, and 24 hours) to supply nutrient solution for chicon forcing at that was predrying treatment on the storability of chicon. The cut-off treatment increased dry matter rate, respiration rate, and ethylene production rate. The dry matter rate of chicon increased, as the cut-off period increased, but the respiration rate and ethylene production rate of chicon was highest in 12 hours and 6 hours cut-off treatment, respectively, and then their rates decreased, as the cut-off period prolonged. The weight loss at cut-off 6 hours treatment was lower than other treatments during $10^{\circ}C$ storage temperature. The cut-off 6 hours treatment showed higher carbon dioxide and oxygen concentration in 10,000 cc/$m^2$/day/atm oxygen permeability film package during storage period than control and showed a little predrying effect but was not statistically significant. At $4^{th}$ day, the ethylene concentration reached higher than other storage day and after that decreased but was not statistically significant. The quality of chicon for 3 hours, 6 hours, 24 hours cut-off treatments on storability showed higher than other treatments, accordingly. The 6 hours cut-off treatment showed the inhibited effect of the degree of browning of chicon cutting plane. The effect of 6 hours cut-off treatment on storability of chicon showed proper predrying effect, reduced moisture loss and browning inhibition apparently during $10^{\circ}C$ storage.

• Journal of Bio-Environment Control
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• v.26 no.2
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• pp.72-77
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• 2017

This study was conducted to examine the effect by application method and concentration of plant growth regulator (PGR) on the growth and runner production of strawberry (Fragaria ${\times}$ ananassa Duch. cv. Maehyang) in a velno-type greenhouse. The seedlings of strawberry were transplanted in pot ($64{\times}27{\times}18cm$) filled with commercial mixed medium (Tosilee) on February 22nd, 2016. The 6-benzylaminopurine (6-BAP) was applied with foliar spray or drench, respectively as 900, 1,200 or $1,500mg{\cdot}L^{-1}$ (50 mL per plant) at 3 weeks after transplanting. Nutrient solution was sufficiently supplied by the drip irrigation as EC $0.65dS{\cdot}m^{-1}$ for rooting during 7 days. After rooting, the 450 mL nutrient solution supplied per pot twice a day (10 min). Plant height and crown diameter of 'Maehyang' mother plant appeared no significantly difference. The other growth characteristics, such as root length, number of primary roots, leaf length, leaf width, leaf area and fresh and dry weights of the shoot or root, were significantly the greatest in the control. And, the SPAD value of strawberry was the highest as 44.2 in the drench with $900mg{\cdot}L^{-1}$. The foiler spray was more effective in runner production than drench, and the number of runners appeared high values at the 900 and $1,500mg{\cdot}L^{-1}$. Whereas, the number of strawberry plantlets was effective in the drench. The results indicate that both growth and the number of runners of strawberry plant were the best achieved by foliar spray application at the $900mg{\cdot}L^{-1}$.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.398-403
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• 2012

This study was carried out to investigate the effect of irrigation method adopted for reducing nutrient solution drainage on the root zone environment, growth and yield of a tomato crop grown in a rockwool medium. The irrigation control methods used were large quantity irrigation at a long interval controlled by only an integrated solar radiation sensor (standard), medium quantity irrigation at a medium interval (zero drainage 1), and small quantity irrigation at a short interval (zero drainage 2) controlled by both an integrated solar radiation sensor and a zero drainage sensor. The amount of the nutrient solution supplied and the drain percentage per plant of the standard, zero drainage 1, and zero drainage 2 were 1.4, 0.9 and 0.8 L, and 23.8, 8.6 and 3.7%, respectively. The average, minimum, and maximum water contents and EC of the standard, zero drainage 1, and zero drainage 2 were 64.5~88% and $1.5{\sim}3.5dS{\cdot}m^{-2}$, 40.3~76.0% and $2.5{\sim}4.0dS{\cdot}m^{-2}$, and 56.3~69.0% and $2.7{\sim}3.7dS{\cdot}m^{-2}$, respectively. There was no difference in leaf width, number of leaves, and stem diameter among the treatments. However, plant height and leaf length decreased in the zero drainage 1 and 2 treatments as compared to the standard. The fruit marketable yield per 10a in the zero drainage 1 and 2 treatments was about 93 and 88%, respectively, of that in the standard treatment.