• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.3
• /
• pp.332-338
• /
• 2012

Soil compaction is one of the major problems facing modern agriculture. Overuse of machinery, intensive cropping, short crop rotations, intensive grazing and inappropriate soil management leads to compaction. This study was carried out evaluate of the effects soil texture and different compaction levels within the soil profile on the soybean root growth and productivity. The soybean plants were grown in $21cm{\o}{\times}30cm$ cylinder pots using three different soil textures (clay, fine loamy and coarse loamy) compacted at different compaction levels (1.25, 1.50, 1.75, and 2.00 MPa). Results revealed that soybean development is more sensitive on penetration resistance, irrespective of soil type. Soybean yield and root weight density significantly decreases with increasing levels of soil compaction in both clayey and fine loamy soils, but not in coarse loamy soil. The highest root weight density was recorded in coarse loamy soils, followed by fine loamy and clay soils, in descending order. The root growth by soil compaction levels started to decline from 1.16, 1.28 and 1.60 MPa for clay, fine loamy and coarse loamy soils. Soybean production in the field experiment decreased about 30% at compacted sub-soils compared to undisturbed soils.

• Journal of Life Science
• /
• v.23 no.6
• /
• pp.796-803
• /
• 2013

Property changes and bacterial characterizations by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) were investigated during the fermentation of Makgeollies by 5 isolated yeast strains. Changes of pH were large between day 0 (pH 6) and day 2 (pH 3) and showed less variation after then. ANOVA analyses revealed that pHs were statistically different with fermentation times (p<0.001), while strains (p=0.60) did not. Acidities were changed from 0.19 to 1.04% and showed rather high increase from day 2, and fermentation times (p<0.001) and strains (p=0.006) represented statistical differences. All strains showed less than 0.150% at amino-type nitrogen contents except S strain showed 0.442% at day 8, and there were no statistical differences with fermentation times (p=0.4558) and strains (p=0.3513). Saccharinities of C strain were higher from day 4, and fermentation times (p<0.0001) and strains (p=0.007) showed statistical differences. Large variation of alcohol concentrations (%) were observed between day 0 (0%) and day 2 (10%) and showed less variation after day 2, and there was no statistical difference with strains. Dominant prokaryotes were Lactobacillus fermentum and Pediococcus pentosaceus, which producing acids and functional materials. Dominant eukaryote was Saccharomyces cerevisiae, which might be resulted from addition of yeasts.

• Journal of Life Science
• /
• v.26 no.4
• /
• pp.414-418
• /
• 2016

This study tested the association between genetic polymorphisms of the isocitrate dehydrogenase 3, beta subunit (IDH3B) gene and economic traits in an F₂ crossbred population of Landrace × Jeju (South Korea) Black pigs. A 304-bp insertion/deletion mutation in promoter region was screened for determining genotypes of the IDH3B gene in a total of 1,105 F₂ pigs. Three genotypes (AA, AB, and BB) were identified in the founder, F₁, and F₂ populations. Association analysis showed significant differences in carcass weights (CW), backfat thicknesses in three positions of the body (4^th-5^th ribs, BF5; 11^th-12^th ribs, BF12; 13^th rib-1^st lumbar, BFL), and carcass lengths (CL) (p<0.05), but not in meat color (MC), eye muscle area (EMA), or marbling scores (MARB) (p>0.05). The F₂ IDH3B BB homozygotes showed heavier CW (80.790±0.725 kg) and shorter CL (101.875±0.336 cm) than the other genotypes (p<0.05). In addition, the BF levels between the 4^th - 5^th and 11^th - 12^th vertebrae were thicker in the carcasses of pigs with the IDH3B BB genotype than with the other genotypes (p<0.05). These results suggested that genetic variations in the IDH3B gene may serve as molecular genetic markers for improving the Landrace × Jeju Black pig crossbreeding systems.

• Journal of Life Science
• /
• v.18 no.7
• /
• pp.963-967
• /
• 2008

The biological activities of water extracts from different fruit parts, such as peel, flesh, and placenta, of oriental melon were investigated. The concentrations of total phenolic in fruit extracts were $816.37\;{\mu}g/ml$, $385.23\;{\mu}g/ml$, and $925.56\;{\mu}g/ml$, respectively. Whereas the total flavonoid content in the peel extracts was $231.21\;{\mu}g/ml$, those in the extract of flesh and placenta were $8.16\;{\mu}g/ml$ and $36.07\;{\mu}g/ml$, respectively. The DPPH free radical scavenging activity of each fruit extract at 10,000 ppm was 34.84% for peel, 10.70% for placenta and 9.26% flesh. The ABTS radical cation decolorizing activity of each fruit extract at 10,000 ppm was in fruit extracts were 72.92% for peel, 48.0% for flesh and 74.31% for placenta. In addition, xanthine oxidase inhibitory activity, ${\alpha}-Glucosidase$ inhibition activity, and tyrosinase inhibition activity of the peel extracts appeared to be higher than those of placenta and flesh. Taken together, these results indicated that the peel part of oriental melon contained higher level of total flavonoid content, and several physiological activities including antioxidation, ${\alpha}-Glucosidase$ inhibition activity, and tyrosinase inhibition activity than did the flesh and placenta parts, and suggested that the peel might have a potential to be applicable as a source for functional foods.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.49 no.3
• /
• pp.167-171
• /
• 2004

The growth of soybean sprout was greatly influenced by watering systems： Fixed watering system (water tub was loaded at ceiling upper of culture box and water was showered by bottom holes) was estimated the better than that of reciprocating watering and tub immersing watering because it could cool down the temperature in culture box and wash the organic substances on the body of sprout. The fixed watering system showed good body color and preventing effect of partial rotting of sprout because it could discharge $\textrm{CO}_2$ gas effectively in culture box and keep the concentration below 5%. The concentration of gases at the bottom (about 30 cm height from basal plate) of culture box in fourth or fifth days was L6% for $\textrm{CO}_2$ and 13-16% for $\textrm{O}_2$, respectively. The optimum gas concentration in culture box was considered to be over 10% for $\textrm{O}_2$ and below 5% for $\textrm{CO}_2$.

• Survey Research
• /
• v.13 no.1
• /
• pp.61-87
• /
• 2012

This research is a part of a fundamental research to form the topographic map of the South Korean society's cultural capital, based on large scale research data. Its purpose is to suggest suitable questions for today's Korean society as well as to compare with previous data accumulated from other nations. For this, this research is to establish theoretical background through critical study on the extensive literature on domestic and foreign cultural capital and collect measures, questionnaires, and data used in important literature and surveys. Based on this, the major domains and levels that should be dealt in the questionnaire were chosen, literature review was conducted for each field; experts were investigated in order to develop questions more suitable for the Korean society considering each domain and level, and qualitative research on the subjects were conducted. This research as seen through the above processes, music genres and culture activities were chosen as major domains, "high/popular" level and "consumption/production" level were chosen as items, and specific items were composed considering Korea's distinct characteristics. Each of these items combine and complement the three aspects of measuring cultural capital(preference, participation, perception), which have been used incoherently in previous researches in measuring the level of possession in cultural capital. This led to developing questions such as the level of liking each item(preference), the level of participating in each item(participation), the level of luxuriousness in each item(perception), and the level of stylishness in each item(perception). This research holds significance in that it critically examines the vast amount of questionnaires used in the past for cultural capital research, provides a large framework to find Korean cultural capital by adding items considering Korea's distinct characteristics, and provides groundwork to fill in the non-Western gap in the discussion of cultural capital, which has been based on the West.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.57 no.4
• /
• pp.441-448
• /
• 2012

This study was carried out to evaluate the productivity of rice cultivation in extremely late season in Korea and to confirm the effects of pot-raising seedling culture in this case by assessing the growth and yield performance of rice cultivars that are well adapted to late culture. Suitable cultivars for extremely late culture should not have premature heading habit when transplanted around late July and also secure appropriate growth duration before heading. Geumobyeo 1 and Manjongbyeo showed small decrease in the emerged leaves in transplanting in late July or early August and heading occurred at the same time relatively without premature heading. At transplanting from late July to early August in extremely late rice cultivation, ripening was relatively good until transplanting on August 5. At transplanting on July 30, accumulated temperature from heading to the first frost was $853^{\circ}C$ and ripening was good enough. However, heading was delayed by low temperature at transplanting on August 10 and ripening was very poor due to low accumulated temperature of below $800^{\circ}C$, causing drastic decrease of rice yield. The rice yield increased in transplanting with pot seedling, especially the effects of pot seedling was higher in Geumobyeo 1, but panicle number was not enough to secure rice yield owing to short growth duration. In order to cultivate rice in extremely late season, we should select adaptive rice cultivars that have suitable growth duration and excellent ripening in low temperature. Here, pot-seedling did a great role to secure early growth and bigger growth amounts.

• Korean Journal of Organic Agriculture
• /
• v.24 no.4
• /
• pp.833-847
• /
• 2016

Drought stress is a major agricultural limitation to crop productivity worldwide, especially by which leafy vegetables, plant leaves eaten as vegetable, could be more lethal. The study was carried out to know the effect of drought tolerance plant growth promoting bacteria (PGPB) on water stress of kale seedlings. A total of 146 morphologically distinct bacterial colonies were isolated from bulk soil and rhizosphere soil of leafy vegetables and screened for plant growth promoting microbioassay in greenhouse. Out of them the isolate SB19 significantly promoted the growth of kale seedlings in increasement of about 42% of plant height (14.1 cm), 148% of leaf area ($19.0cm^2$) and 138% of shoot fresh weight (1662.5 mg) attained by the bacterially treated plants compared to distilled water treated control (9.9 cm, $7.7cm^2$, 698.8 mg). Shoot water content of SB19 treated kale seedlings (1393.8 mg) was also increased about 152% compared with control (552.5 mg). The SB19 isolated from bulk soil of kale plant in Iksan, Korea, was identified as species of Bacillus based on 16S rRNA gene sequencing analysis. We evaluated the effect of drought tolerance by the Bacillus sp. SB19 on kale seedlings at 7th and 14th days following the onset of the water stress and watering was only at 7th day in the middle of test. In the survey of 7th and 14th day, there were mitigation effect of drought stress in kale seedlings treated with $10^6$ and $10^7cell\;mL^{-1}$ of SB19 compared to distilled water treated control. Especially, there were more effective mitigation of drought damage in kale seedlings treated with $10^7cell\;mL^{-1}$ than $10^6cell\;mL^{-1}$. Further, although drought injury of bacterially treated kale seedlings were not improved at 14th day compared with 7th day, drought injury of $10^7cell\;mL^{-1}$ of SB19 treated kale seedlings were not happen rapidly but developed over a longer period of time than $10^6cell\;mL^{-1}$ of SB19 or control. The diffidence of results might be caused by the concentration of bacterial suspension. This study suggests that beneficial plant-microbe interaction could be a important role of enhancement of water availability and also provide a good method for improving quality of leafy vegetables under water stress conditions.

• Korean Journal of Poultry Science
• /
• v.37 no.4
• /
• pp.423-431
• /
• 2010

This work was carried out to investigate on the retail cut yield and the meat quality of crossbred ducks. A total of 360 pullets that were produced from 4 mating methods used in this work. Four mating method were A) native ducks (female) $\times$ native ducks (male), B) meat-type ducks (female) $\times$ native ducks (male), C) native ducks (female) $\times$ meat-type ducks (male), and D) meat-type ducks (female) $\times$ meat-type ducks (male). Ducks were bred at the flat house, and selected nine ducks with similar weights from each treatment at the certain weeks (A, B, C 8 weeks; D 6 weeks). Selected ducks were slaughtered, calculated the retail cut yield(wing, back, neck, breast, leg), analyzed the physico-chemical compositions, and tested the sensory evaluation. Wing and neck meat ratios of D treatment were lowest (P<0.05), and breast meat ratio of B treatment was high (P<0.05) compared to other treatments. pH of duck meat was no difference among treatments, fat and protein contents of B treatment was highest, and collagen contents of D treatment was highest among all treatments. Meat color and physical compositions was no difference among treatments. Juiciness of D treatment meats was highest, and there was no difference between B and D treatments. Finally, mating method of native duck and meat-type duck affected on the retail cut yield, but did not improve on the physico-chemical compositions and sensory evaluation.

• Korea journal of population studies
• /
• v.10 no.2
• /
• pp.17-45
• /
• 1987

This study contributes to understanding women's labor market behavior by focusing on a particular set of labor force transitions - labor force withdrawal and entry during the period surrounding the first birth of a child. In particular, this study provides a dynamic analyses, using longitudinal data and event history analysis, to conceptualize labor force behaviors in a straightforward way. The main research question addresses which factors increase or decrease the hazard rates of leaving and entering the labor market. This study used piecewise Gompertz model, following the guide of the non-parametric analysis on the hazard rates, which allowed relatively detailed description on the distribution of timing of leave and entry to the labor market as parameters of interest. The results show that preferences and structural variables, as well as economic considerations, are very important factors to explain the labor market behavior of women in the period surrounding childbirth.