• Korean Journal of Organic Agriculture
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• v.24 no.3
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• pp.435-451
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• 2016

The objective of the present study was to perform a comparative analysis of the chemical properties of the cultivation site soil and growth characteristics of organically and conventionally cultivated ginseng (Panax ginseng C. A. Meyer). Organically and conventionally cultivated ginseng samples (4-, 5-, and 6-year-old) were collected from 52 fields at 14 locations throughout Korea. The samples were collected over three years from 2013 to 2015, with the collection period between October and November of each year. In order to increase the yield of organically cultivated ginseng, the amount of nutrients was increased to match that of the conventional cultivation system, which highlights the need for proper management in accordance with the standards for chemical properties of soil. Growth duration of organic ginseng was ${\geq}60days$ shorter than that of conventional ginseng and its average yield per 1ha was 60% than that of conventional ginseng. Root weight of organically cultivated ginseng was approximately 54% that of conventionally cultivated ginseng. Rhizome diameter and body shape index of organically cultivated ginseng were lower than those of conventionally cultivated ginseng, indicating that organically cultivated ginseng was thinner and longer than conventionally cultivated ginseng. Root length was greater in 5-year-old conventionally cultivated ginseng with a low percentage of paddy-upland rotation fields. The number of rootlets was lower in 5- and 6-year-old organically cultivated ginseng with a high percentage of direct seeding cultivation. Dry weight was distinctly lower in 5- and 6-year-old organically cultivated ginseng with early defoliation than that of conventionally cultivated ginseng. Incidences of notched belly and root rot tended to be higher in conventional cultivation, with the incidence of notched belly being distinctly higher in 4- and 6-year-old roots and root rot being more prevalent in 5- and 6-year-old roots. Red discoloration and eelworm damage, which are highly affected by soil moisture, were most common in the organically cultivated 4-year-old roots. Organically cultivated ginseng showed early defoliation than conventionally cultivated ginseng, as a result, its yield and weight were low, while the incidence of physiological disorders was low. In order to increase the yield of organically cultivated ginseng, studies on cultivation technology that can overcome early defoliation, as well as soil moisture management that can minimize physiological disorders, are required.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.5
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• pp.37-48
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• 2015

Soil nutrient management is important to maintain the constant productivity of seedling production in the nursery for successful forest restoration. This study investigated the effects of organic manure and chemical fertilizer application levels on the growth, soil properties, and nutrient concentrations of yellow poplar seedlings. One-year-old yellow poplar seedlings were treated with the combination of 3 level organic manures(0, 5 Mg/ha, 10 Mg/ha; mixture of poultry manure, cattle manure, swine manure, and sawdust) and 3 level nitrogen-phosphorus-potassium(NPK) chemical fertilizers(0, 1x(urea, $30g/m^2$; fused superphosphate, $70g/m^2$; potassium chloride, $15g/m^2$), 2x). Organic manure significantly increased the soil pH and the concentrations of nitrogen, available phosphorous, exchangeable potassium, calcium, and magnesium. In contrast, the NPK chemical fertilizer decreased the soil pH and exchangeable calcium concentration, did not affect the soil concentrations of nitrogen and magnesium, and increased the concentrations of available phosphorous and exchangeable potassium. Both organic manure and NPK chemical fertilizer treatments increased the seedling height, root collar diameter, and dry weight by 39% and 25%, respectively. The treatment with manure 5 Mg/ha and NPK 2x chemical fertilizer mostly increased seedling dry weight by 2.6 times more than that of the control. Compared to the effects of the fertilization treatments on the soil properties, the effects on nutrient concentrations in the leaves were relatively small. These findings indicate that organic manure that was derived from livestock byproducts and sawdust can be utilized with chemical fertilizer to improve seedling production as well as conserving soil quality.

• Korean Journal of Weed Science
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• v.30 no.1
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• pp.34-42
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• 2010

Competitive ability, allelopathy, made the common ragweed (Ambrosia artemisiifolia var. elatior ) one of the most dangerous weeds in Korea. The aim of this research was to evaluate the role of common ragweed as test species under laboratory bioassay and glasshouse conditions. Inhibition effect of the leaf extract was higher than that of stem and root parts extracts on germination and seedling growth of weeds. The 5% concentration of leaf extract of common ragweed inhibited the germination rate of Echinochloa crus-galli, Digitaria sanguinalis and Cyperus microiria by 68.3, 74.6 and 87.3%, respectively, as compared to the control. Generally, increasing incorporation concentration inhibited seedling growth of weeds. Incorporation of 5% common ragweed residue significantly reduced the plant length of E. crus-galli, D. sanguinalis and C. microiria by 48, 63 and 68%, respectively, as compared to the control. Also, the values of dry weight were 72, 78 and 71%, respectively. Contrarily, the emergence rate of soybean and corn was not affected by the incorporation of 5% concentration of common ragweed residue. However, the dry weight was inhibited by 37 and 28%, respectively. These results suggest that common ragweed had the ability to control some weed species using toxic compounds like natural herbicide.

• Korean Journal of Weed Science
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• v.17 no.2
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• pp.176-184
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• 1997

The rice(Oryza saliva L.) tolerance to herbicide thiobencarb was determined. At the concentration of thiobencarb 3.0kg ai/ha, Yamabiko, M73 (23)F.A, and wx 139-3-64-220-3-1 were the most tolerant among 643 rice genotypes tested. Thiobencarb reduced plant height until 14 days after treatment by 10% and 13% in tolerant and susceptible genotypes, respectively, but increased plant height in 21 days after treatment for both the genotypes, though partial stunting or dwarfing was observed during the early period until 14 days after treatment. Number of tillers per plant was greater in the plants treated by thiobencarb than in the control, showing that the tolerant genotypes had 2 to 3 tillers which were more than the susceptible ones. Regardless of the genotypes, shoot dry weight was increased by 30 to 50% in 35 days after thiobencarb treatment. The root dry weight increased by 50 to 100% in 35 days after the treatment.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.2
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• pp.53-62
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• 2002

The objectives of this study were to understand the tolerance mechanism of woody plants to water stress and tolerance changes in relation to mycorrhizal formation. Lespedeza cyrtobotrya Miq. commonly used for erosion control in slopes were raised from seeds and transplanted to 120 plastic pots. Sixty pots received the top soil of a Fraxinus americana forest, while remaining 60 pots received the autoclaved top soil. The forest soil contained 1,200 spores per 100g of arbuscular endomycorrhizal fungus, mostly Glomus sp. The plants were raised outside with regular supply of water and mineral nutrients. Two kinds of water deficit treatment and a control were started at the middle of July : cyclic water deficit treatment with 3 cycles of sequential water stress at the point of xylem water potential of about -0.6, -0.6, and -1.7 MPa and recovery, and non-cyclic water deficit treatment with single water stress at about -1.5 MPa. The non-stressed plants received plenty of water throughout the period. In late August the plants were harvested for measurements of dry weight, N, P, carbohydrate contents, net photosynthesis and superoxide dismutase(SOD) activities. Both cyclic and non-cyclic water deficit treatments reduced dry weight by 60% and 40%, respectively, and reduced nitrogen absorption, while increased SOD activities. Water-stressed plants also showed increased carbohydrate contents in the leaves and lowered stomatal conductance. Mycorrhizal inoculation resulted in an average of 40% infection of roots and 2-3 times increase in P absorption in water-stressed as well as non-stressed plants. Mycorrhizal formation also increased shoot-root ratio. The results that SOD activities of water-stressed plants with mycorrhizal infection were significantly lower than those of non-mycorrhizal plants suggest the possibility of improvement of water-stressed condition by mycorrhizal formation. It was concluded that endomycorrhizal formation increased tolerance of Lespedeza cyrtobotrya seedlings to water stress.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.1
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• pp.53-61
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• 1996

Geothermal water contains toxic quantities of sulfur, potassium, sodium, boron, and other toxic elements. These toxic elements can substantially restrict germination and seedling growth in rice plant. Germination percentage, average days required for germination and germination velocity were drastically affected by geothermal water. Binato cultivar has higher germination rate compared to IR58 and Unbong 7. Plant height, root length, leaf number and total dry weight decreased with increased geothermal water concentration. Binato and IR58 showed higher total dry weight than Unbong 7 at 25 percent geothermal water at 15 days after treatment (DAT). Binato and IR58 were relatively more tolerant than Unbong 7 in terms of percentage of leaf damage at 25, 50 and 75％ concentration of geothermal water at 10 DAT. The development of large and small vascular bundles decreased with increasing concentration of geothermal water from control to 50％ in three rice cultivars.

• Korean Journal of Weed Science
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• v.30 no.3
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• pp.215-224
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• 2010

A greenhouse experiment was conducted to determine the effects of medium components and shade treatment on the growth, contents of total phenolics and flavonoids, and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity of Youngia sonchifolia. Substrates combined with coco peat and perlite (ratio 70:30 or 50:50, v/v) showed higher plant length, leaf area, and fresh weight than single substrate (P<0.05). Shade treatment also significantly reduced plant height, root length, leaf areas, and fresh weight (P<0.05) with increasing of the degree. Shading treatment, however, increased contents of total phenolics [mg ferulic acid equivalents $kg^{-1}$ dry wt.] and total flavonoids [mg naringin equivalents $kg^{-1}$ dry wt.] in shoot parts of Y. sonchifoli, showing 110.2 to 119.2 and 128.3 to 146.7 mg $kg^{-1}$, respectively. The antioxidant potential of the methanol extracts from the plants dose-dependently increased DPPH free radical scavenging activity, and the activity was higher in shoots (50.2 to 80.8%) than in roots (47.7 to 49.8%), and in shading treatment than in no shade.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.302-306
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• 2005

This Study was Conducted in 3 glasshouse to examine the Possibility for cultivation of plug seedlings using four growing media containing recycled PET-bottle-particles (PBT) as a medium component. Plug seedlings of 'Seokwang' tomato were grown in media containing $100\%$ PBT, $100\%$ peatmoss, or $50\%$ $PBT+50\%$ peatmoss. A commercial plug medium (Tosilee) was used as the control. All seeds were sown in 128 cell plug trays on July 12, 2004. Seedling growth was measured at 30 days after sowing. Percent seed germination was greater than 95% in all treatments. Plant height, shoot fresh and dry weights, leaf area, and hypocotyl length were the greatest in the control treatment. Root length and weight were the greatest in the $100\%$ PBT treatment, which had a medium pH of 7.3. Leaf area and shoot dry weight were greater in the $50\%$ $PBT+50\%$ peatmoss treatment, than in the $100\%$ PBT treatment, while they were the smallest in the $100\%$ peatmoss treatment. No toxicity symptoms caused by the use or PBT had been observed in any treatment. The results suggest a possibility of recycled PBT, a valuable reusable resource, to be used as a component for medium amendments in horticultural transplant production.

• Journal of Bio-Environment Control
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• v.11 no.4
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• pp.163-167
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• 2002

This study was carried out to investigate the effect of minimum night temperature in the PE house on growth of seedlings of Pinus densiflora and Betula platyphylla in winter season. The experiment was performed with three minimum night temperature regimes,5~8$^{\circ}C$, 10~13$^{\circ}C$ and 15~18$^{\circ}C$. The temperature regimes were maintained for 8 weeks (to April 6) after germination peak, and then were broken by increasing natural temperature. The temperature did not affect the germination rate but delayed the germination by 10 days. Height, root collar diameter growth, and dry weight of two species were reduced by relatively low night temperature. The reduction was more obvious in the dry weight of above the ground measured at 8 weeks after germination. The seedlings grown for 8 weeks at 5~8$^{\circ}C$ showed the lowest T/R ratio. It was also observed that the height growth response in Betula platyphylla seedlings to relatively low temperature was more sensitive than Pinus densiflora.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.157-161
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• 2010

Photosynthetic purple nonsulfur bacterial strains were isolated from the sediments collected from rice paddy fields and sludges of wastewater treatment plant, and their plant growth promoting capabilities were examined. Most well known phytohormones, auxin such as indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) and 5'-aminolevulinic acid (ALA) were detected by HPLC in the culture broth of these isolates. Among the isolated bacteria, Rhodopseudomonas faecalis D15 showed the highest production rate of 769.8 ${\mu}g$/mg protein of IAA, 1323 ${\mu}g$/mg protein of IBA and 7.4 mM/mg protein of ALA in the modified Biebl and Pfennig's medium. R. faecalis C9 showed the highest production rate of 20.82 ${\mu}g$/mg protein of gibberellin. In consequence, the root length and dry weight of the germinated tomato seedling treated with R. faecalis isolates were longer and heavier than those of uninoculated control after 15 days of incubation in the soil. Especially, the dry weight of germinated tomato seedling increased by 119.4% in C9-treated samples after 15 days. These purple nonsulfur bacteria may be utilized as environment-friendly biofertilizer in the agriculture.