• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.122-128
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• 2001

In order to find out the effect of nitrogen fertilizers on soil pH, EC, $NO_3-N$ and lettuce growth, this study was conducted by pot experiment in plastic film house condition. The square-pot which was $42{\times}54.5{\times}22cm$ in length, width and height, respectively, was filled with two kinds of soils in different soil EC as $0.20dS\;m^{-1}$ and $1.13dS\;m^{-1}$. Seven kinds of nitrogen fertilizers (urea, potassium nitrate, calcium nitrate, ammonium nitrate, ammonium sulphate, complex fertilizer A(11-10-10) and complex fertilizer B(12-12-12)) were treated in same standard rate of nitrogen for lettuce, transplanted the six lettuce seedlings of 10 days grown per pot, and have been grown for 38~44 days with three times harvesting. Soil pH was increased with the potassium and calcium nitrate treatments and decreased with ammonium nitrate, ammonium sulphate, complex fertilzer A and B, and the pH of urea treatments was kept the same value as the pH of before experiment. The growing status of lettuce seedling were surveyed during the early period after transplanting and withering of seedling was occured in all treatments. The withering rates were 10% in soil of EC $0.20dS\;m^{-1}$ and 44% and 42% in complex fertilizer and ammonium sulphate treaments, respectively, in soil of EC $1.13dS\;m^{-1}$. $NO{_3}^-$ contents of lettuce were about $1,000{\sim}2,000mg\;kg^{-1}$ based on fresh weight and these contents were considered to be lower to compare the $NO{_3}^-$ level of EU countries.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.6
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• pp.352-360
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• 2002

This study was carried out to find out the effect of Milk vetch(Astragalus sinicus L.) on growth, and yield of rice, physicochemical properties of soil, reduction rate of nitrogen fertilization, and soil improvement under the different plowing time with Milk vetch cultivated in paddy field, plowing at maximum blooming, last blooming, fruiting stages. The fresh weight of Milk vetch at each plowing time of maximum blooming, last blooming and fruiting stage was 22,500, 20,000, $12,500kg\;ha^{-1}$ respectively. Content of total nitrogen at three plowing times was 2.95, 2.66, and 2.47% and the C/N ratio were 15.7, 18.0, and 19.2, respectively. Physico-chemical properties of soil were improved in cultivated milk vetch, the content of T-N. OM and porosity ratio were increased while the content of $P_2O_5$ and bulk density, solidphase ratio were decreased compared to noncultivated milk vetch. Content of $NH_4-N$ in soil was highest plowing at maximum blooming stage and appeared an increasing tendency according to increased nitrogen level. Amount of nitrogen fertilizer by rice was highest plowing at maximum blooming stage and appeared an increasing tendency according to increased nitrogen level. Nitrogen-use efficiency was high in $33kg\;ha^{-1}$ nitrogen level at three plowing times. The number of spikelets per $m^2$ was high in plowing at maximum blooming stage, last blooming stage and the percentage of ripeness was high in fruiting stage of milk vetch. So the rice yield was increased 9%, 8% in $55kg\;ha^{-1}$ nitrogen level plowing at maximum blooming stage, last blooming stage and 1% in $77kg\;ha^{-1}$ nitrogen level plowing at fruiting stage compared to conventional cultivation.

• Journal of Sericultural and Entomological Science
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• v.24 no.2
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• pp.43-54
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• 1983

In a field trial, the influence was studied by measurement of growth and leaf yields and chemical composition (in organic cations and anions and total nitrogen) with two nitrogen dressings (lower nitrogen treatment 25kg and higher nitrogen treatment 75kg urea/10a as the summer fertilizer) after the summer cutting. The results were as follows; 1. With increasingn nitrogen dressing, branch length and weight were enchanced. The fresh weight of leaves was higher to be 273.6kg/10a in the higher nitrogen treatment than in the lower nitrogen treatment on 20 September. 2. The moisture content of leaves lasted above 73% until on 30 August. Afterward it decreased sharply upto 63% on 20 September. In higher nitrogen treatment it was higher about 0.1∼1.8% than in lower nitrogen treatment. The increasing nitrogen dressings combined with leaf condition led to be soft until on 10 October. 3. Dry matter weight of leaves started decreasing around on 10 September, whereas that of branches increased until around 30 September indicating that the dry matter moved to branch and root from leaves. 4. The increase in Ca$\^$2+/ content was particularly evident, whereas the K$\^$+/ and Mg$\^$2+/ decreased with growth. The Ca$\^$2+/ content was much higher in the high nitrogen treatment than in the low nitrogen treatment. 5. With rapid decrease in total nitrogen and water in the leaves around the end of August, the Ca$\^$2+/ and Cl$\^$-/ which were higher in the lower part moved up to the upper part. Whereas the K$\^$+/, H$_2$PO$_4$$\^$-/ and SO$_4$$\^$2-/ which were higher in the upper part moved down to the lower part. 6. Total nitrogen content decreased sharply 3,200me/kg DM to 2,000me/kg DM at the end of August changing the maxmium content of total nitrogen from upper to lower part in the low nitrogen treatment on 12 September and in the high nitrogen treatment on 22 September, and an apex of branches was died and fallen 10 days after respectively. 7. The sum of cation in leaves (∑C) increased from 1400me/kg DM to 1600me/kg DM with growth, wherease that of anions (∑A) was approximatly the same during the whole growing season. As the result, the ionic balance (C-A) increased from 1000me/kg DM to 1200me/kg DM. 8. ∑C, ∑A and (C-A) were higher in the high nitrogen treatment than in the low nitrogen treatment due to be much higher of Ca$\^$2+/ content and higher of NO$\^$-/$_3$, SO$\^$2-/$_4$ and H$_2$PO$_4$$\^$-/ content.

• Korean Journal of Veterinary Research
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• v.10 no.1
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• pp.11-23
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• 1970

Recently Carter(1952) reported the capsule antigens of Pasteurella multocida could be divided into four serological types A,B,C and D by means of precipitation tests. Subsequently he showed that the most sensitive for identification of these types involved the use of capsule substance adsorbed by erythrocytes in hemagglutination test. It may be somewhat difficult to conduct the hemagglutination test in small laboratory, because relatively large amounts of antisera and erythrocytes of the human O type are required for the test. A simple method for serological typing of P. multocida was the slide agglutination test employed by Little et al. (1943) and Namioka et al. (1962), but this method is still in controversy. The author tried adapting Carter's hemagglutination method to the slide method so called "micromethod technique", and studied on the stabilization of erythrocytes for use of slide hemagglutination to P. multocida although many invesigators reported the stabilization of erythrocytes. The results obtained are summarized as follows: 1. A simplified method (slide method) for capsule typing of the organism was developed by adapting Carter's hemagglutination reaction(tube method). Antibody-containing serum can be diluted serially on Boerner's microtest slide with capillary or serological pipetts with a considerable accuracy. The slide reaction can be carried out with case on the slide by adding $0.05m{\ell}$ of antigen-sensitized erythrocytes suspension diluted to one percent on $0.05m{\ell}$ of serially diluted antibody-containing sera, and the final result can be read after 60 minutes at the room temperature ($15^{\circ}C$). 2. It is difficult to determine superiority of inferiority between the slide method and the tube method on the pattern of the reaction of hemagglutination. 3. The pH range of 6.6 to 8.3 is optimal for the slide hemagglutination reaction. 4. The antigen-sensitization against erythrocytes at $37^{\circ}C$ is optimal for the slide hemagglutination. 5. Both the doses and concentration of antigen do not influence the antigen-adsorbing capacity of erythrocytes. 6. The reduction of antigen-sensitizing hours does not influence the antigen-adsorbing capacity of erythrocytes even 30 minutes. 7. The tannic acid treatment against formalinized and non-formalinized erythrocytes showed no effect on the reaction of hemagglutination. 8. The erythrocytes preserved at $4^{\circ}C$ in the ACD solution do not decrease the reactivity on the reaction of hemagglutination for 60 days, while they begin slight hemolysis 30 days after preserving. 9. The stable preparation of erythrocytes can be obtained by treating the cells at $37^{\circ}C$ for 20 hours with from 4 to 8 percent of formalin in saline or buffer. These cells can be preserved at $4^{\circ}C$ for more than 8 months experimented without hemolysis. With low concentration of formalin, the cells were not sufficiently stabilized resulting in the hemolysis after short period of preservation at $4^{\circ}C$. 10. The erythrocytes treated with 16 percent of formalin remain constantly or increase the reactivity for the reaction of hemagglutination. On the contrary, the cells treated with I to 8 percent of formalin decrease the reactivity. 11. There is no difference between nontreated fresh erythrocytes and the erythrocytes preserved in the ACD solution on the reactivity against the hemagglutination, and the erythrocytes treated with 16 percent of formalin showed the reactivity of higher level than that of the above two kinds of erythrocytes. 12. There is no difference between the saline and the isotonic buffer solution on the reaction of hemagglutination.

• Korean Journal of Weed Science
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• v.12 no.2
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• pp.89-101
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• 1992

In this study, various physiological and biochemical experiments were conducted to know whether the selectivity between rice and barnyardgrass treated with bleaching herbicides containing diphenyl ether compounds was also partly based on their basic physiological proterties such as peroxidation ability, membrane stability or antioxidant system. It seemed to be partly based on the differences of their physiological characteristics that barnyardgrass was commonly more susceptible to most of the bleaching herbicides than rice. The scenescence of intact leaf segment was more rapid in barnyardgrass than in rice, indicating that barnyardgrass is weak at early stage. Also pigment metabolic ability, antioxidant enzyme activities(peroxidase, catalase, superoxide dismutase, glutathione reductase) and antioxidant content (tocopherol, ascorbic acid, glutathione, carotenoids) were lower in barnyardgrass on the basic of fresh weight. However, lipoxygenase activity and the content of unsaturated fatty acid which is vulnerable to oxygen radicals were higher in barnyardgrass, suggesting that barnyardgrass seedling bave a properties easy to be peroxidized. The differences of PPIX (protoporphyrin IX) or carotenoid content, which are the primary substances inducing herbicide activity, were not related to the selectivity between rice and barnyardgrass.

• Korean Journal of Weed Science
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• v.12 no.2
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• pp.144-157
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• 1992

The study was conducted to compare the interprete methods and examine the feasibility of mixture use of oxyfluorfen and bensulfuron in controlling principal Paddy weeds, annuals and perennials. Application ratio of both chemicals were obtained from the combinations of 5 levels(0, 5, 10, 15, 20 g ai/ha) of each chemicals, respectively. All the treatments were applied at 5 days after transplanting and water was maintained at 3.0cm in depth. Shoot fresh-weight of weeds was assessed at 35 days after treatments. Data obtained was analysed by Colby, Isobole, Calculus, Regression and EQM method, respectively. The results from the analysis of variance on the principal weeds treated with oxyfluorfen and bensulfuron showed significant interactions at 1% level on both Echinochloa crus-galli and Eleocharis Kuroguwai, and total species at 0.5% level on both Potamogeton distinctus and Cyperus serotinus, but non significant on Scirpus juncoides and Sagittaria pygmaea. Thereafter, the results of the models applied to Echinochloa crus-galli, Eleocharis kuroguwai and total species were as follows ; 1. The Colby method gave values nearly identical to regression estimate method (both multiplicative models) as provided by Akobundu et al. The Colby method and Regression method indicated synergistic toward Echinochloa curs-galli, and total species, but antagonistic toward Eleocharis kuroguwai. 2. The Isobole method shows synergism on Echinochloa crus-galli at $ID_{50}$, and total species at $ID_{60}$ on Eleochari kuroguwai. 3. The Calculus method gave positive signs for the first differentiation and negative signs for the second differentiation except for some rates on Echinochloa crus-galli and total species, but reverse on Eleocharis kuroguwai. These result does not agree with the observed values. 4. ${\theta}$ value from the EQM method was greater than one at all combinations. This result was quite different from those of other methods. 5. The various models did not show the same results, but mixture of oxyfluorfen and bensulfuron tend to have synergistic effect. Weeding effect also was high. Treatment in terms of two chemical combination was expected to reduce rates, and to enhence weeding efficacy compared with single treatment.

• Korean Journal of Weed Science
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• v.15 no.2
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• pp.166-174
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• 1995

This experiment was conducted to investigate a cause of summer depression of cool season turfgrass, using nine cultivars in warm season and twenty-eight cool season turfgrasses. Even though an average of apparent photosynthesis(APS) per fresh weight was 13.09 mg $CO_2$/g/h in warm season turfgrass and 7.75 mg $CO_2$/g/h in cool season turfgrass, the Creeping bentgrass in cool season type was higher than Kikuyugrass and Bahiagrass in warm season type. The optimum temperature for the heighest APS was $30^{\circ}C$ in warm season type and $25^{\circ}C$ in cool season type. In $CO_2$ compensation point(CCP) as an index of dark respiration, it was higher in cool season turfgrass(75.6ppm) than warm season turfgrass(29.5ppm). In warm season type, even though the temperature increased from $25^{\circ}C$ to $40^{\circ}C$ the CCP was not increased. But the higher temperature rises the more increased CCP in cool season type. Dark respiration(DR) was higher in cool season type than warm season type under various temperature conditions, but the increasing ratio of DR with the temperature increment was not so much differed between two types.

• Journal of the Mineralogical Society of Korea
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• v.20 no.4
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• pp.303-311
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• 2007

The consumption of artificially crushed sands exceeds more than 30 percent of the domestic sand supply in South Korea, and its rate is still increasing. For the manufacture of crushed sand granites and granitic gneisses are preferred, fine fractions (i.e. sludge, particles finer than 63 microns) are removed by use of flocculation agents, and its amount occupy about 15 wt%. The sludges consist of quartz, feldspars, micas, chlorite/vermiculite, kaolinites, smectites and occasionally calcite. Among the clay minerals micas are usually predominant, and $14{\AA}$ minerals, kaolinites and smectites are rather scarce. Jurassic granites usually contain more kaolinites and smectites than those of Cretaceous to Tertiary granites, probably due to longer geologic ages. On the other hand, sludge from Precambrian gneiss does not contain kaolinites and smectites. Chemical analyses for the granites and their sludges show rather clear differences in most of major chemical components. Except for $SiO_2,\;Na_2O\;and\;K_2O$, all other components represent rather clear increase. Decrease of $SiO_2$ content is attributed to the relative decrease of quartz in the sludges. And the $Na_2O decrease is caused by a relatively stronger weathering property of albite compared to Ca plagioclase. The $K_2O$ content shows rather small differences throughout the whole samples. The increases of $Al_2O_3$ and other major components resulted from weathering processes and most of colored components are also concentrated in the sludges. Particle size analyses reveal that the sludges are categorized as sandy loams in a sand-silt-clay triangular diagram. The sludge is now classified as industrial waste because of its impermeability, and this result was also confirmed by rather higher hydraulic conductivities. For the environmental problems, and accomplishing effective sand manufacture, more fresh rocks with little weathering products must be chosen.

• Journal of Plant Biotechnology
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• v.38 no.3
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• pp.221-227
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• 2011

This study was carried out to determine optimal medium conditions for mass propagation by bioreactor culture of ever-bearing strawberry (Fragaria ${\times}$ ananassa D.). Two different type of nitride were that mixed $NH_4NO_3$ and $KNO_3$ or added $KNO_3$ only. And nitride concentrations were at the 4 levels of $1/2{\times}$, $1{\times}$, $2{\times}$ and $3{\times}$ that was included $NH_4NO_3$ and $KNO_3$. Sucrose content ranged at 3 levels of $10g{\cdot}L^{-1}$, $20g{\cdot}L^{-1}$ and $30g{\cdot}L^{-1}$ and medium pH were at the 3 levels of 4.6, 5.6 and 6.6. In bioreactor culture, medium that are included $NH_4NO_3$ and $KNO_3$ together in MS medium was suitable for mass propagation. Medium EC rose rapidly when the nitride concentration was increased. For that reason, plantlet growth was inhibited. Shoots of nitride $1/2{\times}$ concentration was 10.8 ea and $1/2{\times}$ concentration was suitable for shoot propagation. Fresh weight of sucrose $30g{\cdot}L^{-1}$ was 3,101 mg which was heaviest and aerial and ground part were higher than the other concentration. Shoots were increased in proportion to the increasing concentration of sucrose. In the pH condition, from pH 5.6 to 6.8 were appropriate for the optimum growth of aerial and ground part of plant. From the results, in bioreactor culture for mass propagation, MS medium was suitable $1/2{\times}$ concentration that was included $NH_4NO_3$ and $KNO_3$ together, and added $30g{\cdot}L^{-1}$ of sucrose, and then adjusted pH between 5.6 and 6.6.

• Journal of Life Science
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• v.7 no.2
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• pp.142-148
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• 1997

This study was carried out to clarify seasonal changes of chemical compositions and their interrelation in leaves, shoots and berries treated with gibberellin($GA$_{3}$)for seedless grapes in ‘Delaware’grapevines. the clusters were dipped twice with 100ppm $GA_{3}$: 10 days befor and after the full bloom. The reaults obtained as follows; 1. Cumulative growth curve of berry fresh weight showed a double sigmoid curve and the characteristics of three distinctive growth stages(I, II, III)were weekened with $GA_{3}$ treatment. 2. while the contents of ash, total carbon, total nitrogen and total carbohydratd had little reation with edvelopment and ripeness of berries, those of total sugar and starch jad close relation, viz., they decreased with enlargement and maturity fo berries, but increased rapidly after harvest in leaves and shoots. Especially, total sugars in leaves and shoots decreased coincidently with starch-increasing in shoots at November. 3. The contents of total soluble solid and reducing sugar in berries increased rapidly at growth stage III, but those of total titratable acidity and organic acid decreased coincidently with sugar-increasing. 4. The berry-hardness increased until growth stage I, and then stagnated until gtowth stage II, and then increased rapidly at growth stage III. pH of berry-juice decreased until growth stageII, afterwards increased at growth stage III. 5. By correlation and path coefficient analysis between qualitative characters and the ratio of total soluble solid to titratable acidity($^{\circ}$Brix/Acidity), total correlation coefficients were all highly significant. Of these characters, pH and viscosity of berry-juice were positive, but brightness and hardness of berry, negative. The direct effect of pH on $^{\circ}$Brix/Acidity ratio, p4y=0.9090, was large positively and those of berry-hardness and juice-viscosity, p1y=0, 5938, median and, p2y=0, 3550, small, respectively. Direct effect of brightness was negatively small.