• Korean Journal of Soil Science and Fertilizer
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• v.10 no.1
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• pp.61-67
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• 1977

A study was conducted in order to compare the topdressing method of the conventional fertilizers as control and the deep application method of the ball complex fertilizer newly developed. The ball complex fertilizer consisted of 5% of nitrogen, 5% of phosphorus, and 7% of potassium. Basal application of nitrogen for the rice plant was the same for both control plots and ball complex plots. One ball complex fertilizer per four hills was applied at depth of 12~13cm 35days before heading stage while control plot received three times topdressing at different growth stages as usual practice. The results obtained were as follows. 1. The ball complex fertilizer applied in the soil was continuously utilized by the rice plants until harvest time while nitrogen and potassium uptake of control plots was reduced rapidly after heading stage. Daily uptake of nitrogen and potassium per hill at maturing stage were 0.45mg and 0.68mg in control plots, but 4.80mg and 7.0mg respectively in ball complex plots. 2. Dry matter productivity of the rice plant in control plots, well coinciding with nutrients uptake pattern, was maximum just after heading stage decreased at maturing stage. But dry matter productivity in ball complex plots was much higher at maturing stage than at heading stage. 3. Ball complex application increased effective tillering rate, causing higher panicle number per hill. 4. Ball complex application brought about 528kg/10a of hulled grain yield while the conventional practice 423kg/10a. 5. Deep application of ball complex was superior to usual practice in terms of yield components such as panicle number per hill, filled grain number per panicle, maturing rate, and 1,000 grain weight. 6. From the morphological characteristics point of view, the deep application of ball complex made the flag leaf and the 2nd leaf heavier, larger and broader as compared to control treatment. 7. It is considered that by applying the ball complex fertilizer at depth of 12~13cm sufficient amount of nitrogen and potassium could be utilized by rice plants during the maturing stage and assimilated in the leaf blade, consequently making the flag leaf and the 2nd leaf bigger and healthier. The fact can easily explain that the ball complex plots had higher capacity of photosynthesis, less discoloration of lower leaves, bigger leaf area index, and better grain yield as compared to the conventional practice. In conclusion the deep application method of the ball complex fertilizer was superior to the routine topdressing method of the usual fertilizers.

• Korean Journal of Agricultural Science
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• v.30 no.2
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• pp.128-138
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• 2003

The bacterial density of partially processed horticultural crops in the commercial market was relatively high probably due to improper handing or processing. Between crops, the bacterial density was low in peeled garlic and ranged above $10^8cfu{\cdot}g^{-1}fw$ in other crops. Especially in brake fern, the bacterial density was the highest and non food materials such as packing strips were found. There was difference in the effects of ozone-treated water washing treatment between crops. In root crops such as burdock and lotus root, ozone showed positive effect on preventing discoloration as well as lowing bacterial density resulting in the increase of marketing period. Any positive effect was not found when sliced crops were treated over 5 min at $0.3mg{\cdot}L^{-1}$ of dissolved ozone. In lettuce slices, leaf tissues were severely discolored and rapidly soften at $0.3mg{\cdot}L^{-1}$ for 2 min dipping. Ozone was highly effective on inhibiting bacterium propagation and off-flavor. This effect was more stronger in Fischer ligulariata than brake fern, probably due to the difference of tissue thickness. Results indicated that ozone-treated water washing had a strong potential to improve the market quality of partially processed horticultural crops including dried wild greens and sliced root crops.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.1
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• pp.63-67
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• 1987

A laboratory experiment was conducted to find out the concentration of phytotoxin in intensively cultivated hot-pepper, garlic and chinese cabbage, and effects of these phytotoxin to the germination and growth of young hot-pepper plant. Also this experiment presents describes of the bio-assay method and results of phytotoxin application to the toxicity of hot-pepper plant. The results obtained were summarized as follows; 1. A series of non-volatile (aromatic) phenolic compounds such as hydroquinone, benzoic-, p-hydroxybenzoic, and vanillic acid were quantitatively and qualitatively analysed using BSA(N, O-bis(trimethylsilyl)acetamide) by means of gas chromatography method. 2. Phytotoxin as hydroquinone, benzoic-, p-hydroxybenzoic- and vanillic acid were determined in intensively cultivated hot- pepper, garlic and chinese cabbage. Highest concentration of phytotoxin was obtained in hot-pepper cultivated soil. 3. Direct toxic action of the applied phytotoxin to the germination and young hot-pepper plant growth was observed at the levels of 200 ppm. Benzoic acid was obtained the highest toxicity to the young hot-pepper plant growth. 4. Mode of actions of phytotoxins to the young hot-pepper plant growth were observed as stunting of stem elongation, discoloration of leaf and oxygen depletion from consideration as causes of symptom.

• Korean Journal of Environmental Agriculture
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• v.19 no.5
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• pp.401-418
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• 2000

1. Production of the artificial zeolite from coal ash Coal fly ash is mainly composed of several oxides including $SiO_2$ and $Al_2O_3$ derived from inorganic compounds remained after burning. As minor components, $Fe_2O_3$ and oxides of Mg, Ca, P, Ti (trace) are also contained in the ash. These components are presented as glass form resulting from fusion in the process of the combustion of coal. In other word, coal ash may refer to a kind of aluminosilicate glass that is known to easily change to zeolite-like materials by hydrothermal reaction. Lots of hot seawater is disposing near thermal power plants after cooling turbine generator periodically. Using seawater in the hydrothermal reaction caused to produce low price artificial zeolite by reduction of sodium hydroxide consumption, heating energy and water cost. As coal ash were reacted hydrothermally, peaks of quartz and mullite in the ash were weakened and disappeared, and new Na-Pl peaks were appeared strengthily. Si-O-Si bonding of the bituminous coal ash was changed to Si-O-Al (and $Fe^{3+}$) bonding by the reaction. Therefore the produced Na-Pl type zeolite had high CEC of 276.7 $cmol^+{\cdot}kg^{-1}$ and well developed molecular sieve structure with low concentration of heavy metals. 2. Utilization of the artificial zeolite in agro-environment The artificial zeolite(1g) could remove 123.5 mg of zinc, 164.7 mg copper, 184.4 mg cadmium and 350.6 mg lead in the synthetic wastewater. The removability is higher 2.8 times in zinc, 3.3 times in copper, 4.7 times in cadmium and 4.8 times in lead than natural zeolite and charcoal powder. When the heavy metals were treated at the ratio of 150 $kg{\cdot}ha^{-1}$ to the rice plant, various growth inhibition were observed; brownish discoloration and death of leaf sheath, growth inhibition in culm length, number of panicles and grains, grain ripening and rice yield. But these growth inhibition was greatly alleviated by the application of artificial zeolite, therefore, rice yield increased $1.1{\sim}3.2$ times according to the metal kind. In addition, the concentration of heavy metals in the brown rice also lowered by $27{\sim}75%$. Artificial Granular Zeolites (AGZ) was developed for the purification of wastewater. Canon exchange capacity was 126.8 $cmol^+{\cdot}kg^{-1}$. AGZ had Na-Pl peaks mainly with some minor $C_3S$ peaks in X-ray diffractogram. In addition, AGZs had various pore structure that may be adhere the suspended solid and offer microbiological niche to decompose organic pollutants. AGZ could remove ammonium, orthophosphate and heavy metals simultaneously. Mixing ratio of artificial zeolite in AGZs was related positively with removal efficiency of $NH_4\;^+$ and negatively with that of $PO_4\;^{3-}$. Root growth of rice seedling was inhibited severely in the mine wastewater because of strong acidity and high concentration of heavy metals. As AGZ(1 kg) stayed in the wastewater(100L) for 4days, water quality turned into safely for agricultural usage and rice seedlings grew normally.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.263-272
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• 2012

The potential as natural herbicide of d-limonene natural agent was conducted on several weeds in a greenhouse and Sciyos angulatus in field condition. Herbicidal activity of foliar application at a concentration of 100 and 200 kg ai $ha^{-1}$ of d-limonene on seven weed species was completely killed in a greenhouse condition. Also, d-limonene at a concentration of 50 kg ai $ha^{-1}$ was completely killing on Abutilon theophrasti, Aeschynomene indica, Echinochloa crus-galli and Digitaria ciliaris 3 days after treatment. While pre-emergence treatment of d-limonene concentration of 12.5 to 200 kg ai $ha^{-1}$ showed not significant visible damages. Phytotoxic symptoms of d-limonene by foliar treatment were characterized by wilting and burn-down of leaves and stems followed by discoloration, finally, plant death. Crop selectivity at d-limonene concentration of 100 kg ai $ha^{-1}$ over to five main crops including Zea mays by foliar application was not at all. Field trial of foliar treatment with d-limonene 70 to 140 kg ai $ha^{-1}$ have effectively controled over 5~20 leaf stages of S. angulatus at the natural habitats. And herbicidal efficacy of foliar application on S. angulatus with carrier volume in field condition was increased with dose dependent manners. These results suggest that d-limonene is considered possible as herbicide, and may be further optimized for natural agent for environmental friendly natural herbicide.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.3
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• pp.364-368
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• 2014

This study investigated ginseng growth and ginsenoside contents after control a reserved ginseng cultivation land using various green manure crops for stable ginseng cultivation. Followings are results obtained from this research. After cultivate the green manure crops, microbial flora in soil was diversified, organic matter and total-N content increased, but salt content decreased. The highest output obtained from the wheat cultivated area among various green manure corps. Growth of shoot and root of two years old ginseng increased significantly at the green manure crop cultivated area. Specially, the wheat cultivated area was the most effective in growth. Also, the rate of the leaf discoloration at the aerial part and the rusty root at the root was the least at the wheat cultivation area. Meanwhile, the ginsenoside content was the most at the wheat cultivation area. Thus, the reserved ginseng cultivation land could be managed by cultivating wheat for effective ginseng growth.

• Research in Plant Disease
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• v.13 no.1
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• pp.15-19
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• 2007

A wilt disease on the greenhouse-grown chrysanthemum occurred at Kumi, Masan and Busan, Korea in $2003{\sim}2005$. Symptoms of wilting, yellowing, and marginal burning started from lower leaves and progressed upward. Early symptoms often appeared on one side, involving only one part of the plant or one side of individual leaves or stems without a vascular discoloration. Vascular tissues of the infected leaf-base's discolored to brown. Fungal isolates obtained from discolored tissues were identified as Verticillium dahliae based on its cultural and morphological characteristics. The fungus showed whitish to creamy colony pattern with abundant dark brown to black elongated microsclerotia on PDA. Conidiophores were verticillately branched and conidia were ellipsoidal to sub-cylindrical shape, and measured as $2.5{\sim}8.8{\times}2.0{\sim}3.8{\mu}m$. Pathogenicity tests by root dipping resulted in similar symptoms observed in the naturally infected chrysanthemum in fields.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.15
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• pp.99-113
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• 1974

This experiment was carried out to find reasonable semi. hot seedbed system for early transplanting of "Tongil"rice cultivar. The quality of the young rice-plants, yield, and the occurrence of the reddish dry leaves were not significant differences between the seedbed with polyethylene tunnel and that of Rat covering. The per cent of healthy seedling of the soil preparation with the dry soil plowing was increased than that of the water soil plowing. The stability of the seedling cultivation of the thin layer straw mulching seedbed beneath the polyethylene film was higher than that of the common flat seedbed system.ed system.

• Research in Plant Disease
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• v.18 no.2
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• pp.101-108
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• 2012

In 2006, pinewood nematode, Bursaphelenchus xylophilus, was isolated from about 50 years old trees of Pinus densiflora and P. koraiensis showing leaf-wilt and -drying symptoms in Gwangju, Gyeonggi-do and Chuncheon, Gangwon-do. Isolation of pinewood nematodes from sapwood of infected pine trees showed no difference in population density between tree species and among the sampling heights on the main stem. Migration of pinewood nematodes in the host tree were investigated by inoculation of red pine (P. densiflora, 3 years old) seedlings with B. xylophilus. The nematodes seemed to move in red pine seedlings prior to multiplication and it might have taken about 20 days to start multiplication and expression of symptoms including wilt and dieback. In initial time after inoculation, nematodes started migration through the cortical resin canal from inoculated site and further showed upward and downward movements. More nematodes were observed in cortical resin canal during early period of inoculation and later in resin canal of xylem and tracheid also while, the pith still remained free from nematode. The density of B. xylophilus was higher in seedlings of low-vigor with poor root growth than in seedlings of normal root growth. Seedlings showing high density of B. xylophilus exhibited stem discoloration and secondary infection by fungus at the inoculation site.

• Journal of Mushroom
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• v.18 no.4
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• pp.339-343
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• 2020

This study aimed to optimize total nitrogen (TN) content in the medium and the growth temperature to improve the shelf life of Pleurotus eryngii Keneutari No. 2. We investigated the growth characteristics and changes in the O2/CO2 content in polypropylene film and performed sensory evaluations during cold storage under 1.5%, 1.8%, 2.1%, and 2.4% TN and at temperatures of 9℃, 12℃, and 15℃. The diameter and weight of the fruit bodies tended to increase with increasing nitrogen content, regardless of the growth temperature, and the highest weight per bottle (149.5 g) was obtained at 12℃ and 2.4% TN. Regardless of the nitrogen content, leaf color deepened with decreasing temperature. The gas concentration in the film, which changes depending on storage time, was maintained for the longest period at 9℃ and 2.1% TN. The sensory evaluation revealed no difference between the different nitrogen conditions tested, and the odor, discoloration, and decay were similar at 15℃ and 9℃ until day 28 of storage.