• Korean Journal of Soil Science and Fertilizer
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• v.38 no.2
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• pp.85-91
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• 2005

Nutrients are built up in paddy soils after greenhouse vegetable cultivations with relatively high rates of chemical fertilizers and composts during winter season, and the continuous nutrient accumulation is problematic in crop cultivation. Rice cultivation after greenhouse vegetables is one option for removing the accumulated nutrients in the soils. The object of this experiment was to examine the effect of reduced fertilization to rice on the removal of accumulated soil nutrients and rice yield in greenhouse vegetables and rice cropping system. Experiments were carried out at Changwon and Uiryeong in Gyeongnam province in 2001. The cropping systems were watermelon-rice and pumpkin-watermelon-watermelon-rice in Changwon and Uiryeong, respectively. The soils were Gangseo series (coarse loamy, mixed, nonacid, mesic family of Aquic Fluventic Eutrochrepts) at Changwon and Hampyeong series (fine loamy, mixed, mesic family of Fluvaquentic Dystrochrepts) at Uiryeong. Treatments of conventional fertilization ($N-P_2O_5-K_2O=11-4.5-5.7$, $kg\;10a^{-1}$), no basal fertilization, no top dressing, and no fertilization were included in the experiments. Plant growth and total nitrogen content in the plant were greater as the amount of fertilizer applied were increased. Whereas $SiO_2/T-N$ rate in rice plant and nitrogen use efficiency were greater as the amount of fertilizer applied were reduced. Rice yields were not significantly different among the treatments of conventional, no top-dressed, and no-basal fertilization in Uiryeong, and the rice yields were significantly also not different between the treatments of conventional and no top-dressed in Changwon. The removal of salts in soils after rice cultivation was the highest at the treatment of no-basal fertilization in both of the sites. Therefore, reduced fertilization for rice cultivation after greenhouse vegetables could remove salts accumulated in paddy soils without any significant reducing of rice yield.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.354-363
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• 2007

In order to investigate the optimum rate and interval of silicate fertilizer application for rice cultivation, Chucheong byeo variety, one of commonly cultivated rice cultivar in Korea was planted on two different wetland rice soils located on Hwaseong-si from 2002 to 2005; Jisan series(a member of the fine loamy, mixed, mesic family of Fluvaquentic Endoaquepts), known as "Productive Paddy Soil", without any conspicuous limiting factor, and Seokcheon series (a member of the coarse loamy, mixed, nonacid, mesic family of Fluvaquentic Endoaquetps), known as "Sandy Paddy Soil", sandiness being major limiting factor. There were three rate treatments of silicate fertilizer application; the amount of silicate fertilizers needed to adjust the available soil silicate contents to 130, 200, and $270mg\;kg^{-1}$ was applied, in the first year only. There was an additional plot; applying the amount of silicate fertilizer needed to adjust soil available silicate to 130 ppm every year, which would serve as the base for the evaluation of residual effects of silicate fertilizers in the plots where different rates of silicate fertilizer were applied. From the yield data in first year, it was found that optimum available silica in the soil are $154mg\;kg^{-1$ and $160mg\;kg^{-1}$, in Jisan and Seogcheon soils, respectably. The duration of residual effects of silicate fertilizer was different depending upon the amount of applied silicate fertilizers and the soils. The higher the application rate, the residual effect lasted longer, and the residual effect was lasted longer in Jisan(clay loam) soil than in Seogcheon(sandy loam) soil. During four years, sum of the rate of contribution to increase available soil silica of applied silicate fertilizer in different soils ranged 18.6% and 24.1% in Jisan soil and Seogcheon soil, respectively. This may suggest that much portion of applied silicate would be either lost from the soil or remain in the soil as insoluble form. This deserves further study.

• Korean Journal of Psychosomatic Medicine
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• v.23 no.2
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• pp.93-99
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• 2015

Objectives : The purpose of this preliminary study was to investigate job stress and stress coping strategy among workers in a regional statistics office. Methods : A total of 133 workers in regional statistics office participated in this study and they were divided into two groups, survey group(n=109) and support group(n=24) depending on relation to statistical survey task. They were asked to respond to Short Form of Korean Occupational Stress Scale(KOSS-SF) and Stress Coping Strategy(SCS) to investigate sociodemographic characteristics, job stress, and stress coping strategy. Results : The proportion of the 133 participants in the sample was 59(44.4%) of men, 74(55.6%) of women. There were no significant differences in KOSS-SF scores in relation to age, sex, education, and marital status, while the KOSS-SF scores were significantly different between the two groups. In regard to the subscales of KOSS-SF, the two groups had significant differences in insufficient job control, interpersonal conflict, job insecurity, and organization system. In addition, the total score of KOSS-SF had a negative correlation with problem-focused coping strategy and social support coping strategy of SCS. Conclusions : Our results suggest that workers of survey group had more job stress compared to those who works in support group in regional statistical office. In addition, in comparison with workers of support group, both men and women of survey group get stressed when they were confronted with interpersonal conflicts. Our results suggest that using problem-focused coping and social support coping strategy lowers job stress.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.3
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• pp.201-209
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• 2021

There is a growing interest in rice cultivation on farms with irrigation facilities in desert climates. We investigated the growth characteristics and yields of two rice cultivars (FL478 and Asemi) irrigated at field capacities (FCs) of 80%, 100%, and 120% in a lysimeter with coarse sandy soils. The results showed that at the heading stage, the FC 100% treatment had the highest plant height and number of tillers between the two cultivars. At the harvest period, the culm and panicle lengths of both cultivars at FC 100% were similar to those of the control. In contrast, the number of panicles, grain number per panicle, and percentage of ripened grains were the highest in the control. Moreover, FL478 and Asemi had the highest grain yields of 1.40 and 2.20 kg·pot^-1 in the control, respectively. For both cultivars, the grain yields of the FC 100% and FC 120% treatments were approximately 70% of the control. In comparison, FL478 and Asemi had the highest water productivity of 0.45 and 0.63 kg·m^3-1 for the FC 80% treatment, followed by the FC 100% treatment (0.42 and 0.59 kg·m^3-1, respectively), which was nearly 14.3% and 20.3% higher than that of the control. Therefore, we found that irrigation at FC 100% is anticipated to be effective in managing surface drip irrigation for rice cultivation in desert climates in arid environments, while maintaining rice yields.

• Journal of The Korean Association For Science Education
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• v.41 no.4
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• pp.297-310
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• 2021

This study explores the characteristics of within-school and across-school science teacher professional learning communities (hereafter, PLC) qualitatively. In-depth focus group interviews were conducted with science teachers belonging to seven PLCs within the science core school and three PLCs across schools. Interview questions include identity and motivation, major activities, and outcomes of PLC, as well as shortcomings and support plans for PLC. The results include both within-school and across-school science teacher PLCs formed for professional development related to science teaching and learning. Both science PLCs participated in the study showed the characteristics of a 'practice community' that developed a cooperative relationship through reciprocal participation, focusing on shared issues among members. Regarding issues, within-school PLCs focused on microscopic problems such as curriculum reconstruction of subject-matter, while across-school PLCs focused on macro problems such as teacher professional development. Regarding activities and roles as PLC, within-school and across-school science PLCs shared such features as collaborative professional development, and interpersonal education such as mentoring for novice teachers. In terms of PLC's influence and outcomes, science teacher PLCs has a positive effect not only on the teachers themselves, but also on the students and the teacher culture in the school. In addition, science teacher PLCs need improvement of the physical conditions for community operation, and software support such as protocol provision for PLC operation and joint research or re-education with universities. In particular, joint research between universities and science teacher PLCs shows the future orientation of the PLC as an 'inquiry community'. Based on the results, the necessity of active support for science PLC, the necessity of developing a cooperative system between science teacher PLC and universities, and ways to spread the PLC of science core schools to that of general schools were proposed.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.312-319
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• 2021

This study was conducted to investigate the effect of elevated carbon dioxide on the growth and physiological responses of peach 'Mihong' (Prunus persica). We simulated three different carbon dioxide conditions based on climate change scenarios RCP 8.5 in the sunlight phytotron rooms from April 22 to July 6, 2020; 400 µmol·mol^-1(present condition), 700 µmol·mol^-1 treatment(expecting carbon dioxide concentrations in mid-21st century), 940 µmol·mol^-1 treatment (expecting carbon dioxide concentrations in late 21st century). The average of maximum photosynthesis rate at 700 µmol·mol^-1(16.06 µmol·CO₂·m^-2·s^-1) was higher than those at 400 µmol·mol^-1(14.45 µmol·CO₂·m^-2·s^-1) and 940 µmol·mol^-1(15.96 µmol·CO₂·m^-2·s^-1) from May 22 to July 2. However, stomatal conductances at 700 µmol·mol^-1 and 940 µmol·mol^-1 were lower than those at the control. Also, the carbon dioxide saturation point in all treatments was reduced from 1,200 µmol·mol^-1 in the early stage of growth to 600-800 µmol·mol^-1 in the late stage of growth. The stomatal densities were decreased as carbon dioxide increased. The shoot lengths were decreased while the carbon dioxide was increased, but the increase of trunk diameter and leaf areas, shoot numbers were not statistically different. The fruit weight at 700 µmol·mol^-1(152.5 g) was higher than those at the control(141.8 g) and 940 µmol·mol^-1(147.4 g). The soluble solids were higher at 700 µmol·mol^-1, 940 µmol·mol^-1 compared to the control. These results suggest that a carbon dioxide elevated to 700 µmol·mol^-1 in the future may give a positive effect on the yield and fruit quality of peach 'Mihong' while a carbon dioxide elevated above 940 µmol·mol^-1 may affect negatively such as early senescence and loss of fruit set.

• Journal of Mushroom
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• v.19 no.3
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• pp.200-209
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• 2021

In this study, a low-salt Lentinula edodes soybean paste (LSLESP) with improved palatability and storability relative to traditional Korean soybean paste was developed by utilizing low quality log cultivation of L. edodes. We also conducted quality characteristic analyses of spread jam made from low-salt L. edodes soybean paste (SJLLESP). The lowest salinity content and the highest L (brightness) value was found in LSLESP. According to proximate compositions analysis, crude protein, crude fat, and ash content were higher in commercial soybean paste than in LSLESP. Glucose, fructose, and maltose were the only free sugars detected in commercial soybean paste, whereas arabinose and fucose were additionally detected in LSLESP. Only two types of organic acid, were detected in common in commercially available soybean paste and LSLESP. Four types of organic acid, were detected in SJLLESP due to its added ingredients. The major free amino acids in commercially available soybean paste and LSLESP are histidine, glutamic acid, and arginine. Total amino acid, content was higher in LSLESP (54.81 mg%) than in commercial soybean paste (49.26 mg%). Total free amino acid, content in SJLLESP was 43.01 mg%. Ergosterol and β-glucan contents were highest in SJLLESP. The elevated ergosterol and β-glucan content in low-salt LSLESP relative to commercial soybean paste was significant. In conclusion, LSLESP and SJLLESP contain useful components from L. edodes, and offer the advantage of low salinity. LSLESP and SJLLESP could thus contribute to the development of health foods using L. edodes.

• Journal of Applied Biological Chemistry
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• v.64 no.3
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• pp.253-261
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• 2021

In this study, the ginseng sprout has produced through smart farm was classified according to its size and divided into above-ground (AG) and below-ground (BG) parts to compare ginsenoside contents and antioxidant activity. In the case of the AG part, the total phenolic contents were the highest at 5.16 mg/g in medium (M) size and the lowest at 2.23 mg/g in largest (L) size. The BG part also showed the highest content in the M size, but there was no significant difference. Also, the total flavonoid contents were also high in the M size in both the AG (5.16 mg/g) and BG (1.28 mg/g) parts. The major ginsenosides in the AG part were Re (20.33-24.15 mg/g) > Rd (11.36-27.42 mg/g) > Rg1 (4.48-5.54 mg/g) and the main ginsenosides in the BG part were Rb1 (5.09-8.61 mg/g) > Re (4.48-5.54 mg/g) > Rc (3.11-4.11 mg/g) in orders. In the case of M size, Re and Rd were approximately 4- and 19-folds higher at 24.15 mg/g and at 27.42 mg/g in the AG part and 5.20 mg/g and 1.43 mg in the BG part, respectively. In addition, F3 and Rh1 were detected in the AG part, but not in the BG part. 2,2-diphenyl-1-picrylhydrazyl (74.95%), 2,4,6-azino-bis (3-ethylbenzothiazoline-6-sulphnoic acid) diammonium salt (94.47%), and hydroxyl (70.39%) radical scavenging activities and FRAP (2.169) assay were the highest in M size than other sizes.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.320-327
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• 2021

Freezing damage to fruit trees is frequently occurring due to cold in winter and low temperature in spring to abnormal weather caused by global warming. In particular, the freezing injury of deciduous fruit trees is highly dependent on the developmental stages of the flower buds. And the cold resistance is weakened as the growth progresses, so it is most vulnerable period from flowering to petal fall(post-bloom). Therefore, this study was conducted to analyze the cause of the freezing injury caused by severe low temperature to 'Fuji', which has a late flowering period more than 'Hongro' in April 2020. We investigated freezing injury rate in 'Fuji' and 'Hongro' apple trees damaged by natural low temperature at Boeun-gun, Chungbuk province in Korea. In addition, flower buds in the same developmental stage (tight cluster) were treated artificially low temperature to investigate the injury rate for accurate comparative analysis between varieties, and to analyze the soluble sugar and hormone contents in the flower buds. As a result of survey in natural low temperature, 'Fuji' had a higher injury rate than 'Hongro' in both orchards, and in particular, B orchard 'Fuji' had the highest injury rate of 60.5%. Also there were significantly difference in the freezing injury rate between 'Fuji' and 'Hongro' in artificially low temperature treatments. As a result of analyzing the soluble sugar contents in 'Hongro' was higher than 'Fuji'. Also ABA, IAA and SA contents were more increased in the damaged tissue than in the normal flower buds by low temperature treatments. Consequently, it was assumed that the freezing injury was closely related to soluble sugar contents in the flower buds. In particular, the freezing injury rate was negatively correlated with the sorbitol contents.

• Journal of Family Resource Management and Policy Review
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• v.25 no.2
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• pp.53-78
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• 2021

The concept of household labor is composed of housework and family care, and it provides a framework for understanding daily life from the perspective of work-life balance. The purpose of this study was to investigate the household labor time of Korean adults by gender and generation over the last 20 years. Data was taken from the five Statistics Korea Life Time Surveys from 1999 (t1) to 2019 (t5) (n=69,196). The major results are as follows: first, gender and generation were found to have a significant relationship with household labor time over the study period. Household labor time for females was 3.8 times that of males in 1999, but females' household labor time decreased over the next 20 years while males' increased, including both housework and family care. The female participation rate in household work also remained steady, while that for males increased. Second, in the younger and middle generations, a similar gender and generational pattern was seen. Third, in the older generation, household time and participation rates for both females and males increased. The family welfare policy and theoretical implications of these results are discussed.