• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.321-327
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• 2006

In Korea, there is a growing competitive for water resources between industrial, domestic and agricultural consumer, and the environment as many other OECD countries. The demand on water use is also affecting aquatic ecosystems particularly where withdrawals are in excess of minimum environmental needs for rivers, lakes and wetland habits. OECD developed three indicators related to water use by the agriculture in above contexts : the first is a water use intensity indicator, which is expressed as the quantity or share of agricultural water use in total national water utilization; the second is a water stress indicator, which is expressed as the proportion of rivers (in length) subject to diversion or regulation for irrigation without reserving a minimum of limiting reference flow; and the third is a water use efficiency indicator designated as the technical and the economic efficiency. These indicators have different meanings in the aspect of water resource conservation and sustainable water use. So, it will be more significant that the indicators should reflect the intrinsic meanings of them. The problem is that the aspect of an overall water flow in the agro-ecosystem and recycling of water use not considered in the assessment of agricultural water use needed for calculation of these water use indicators. Namely, regional or meteorological characteristics and site-specific farming practices were not considered in the calculation of these indicators. In this paper, we tried to calculate water use indicators suggested in OECD and to modify some other indicators considering our situation because water use pattern and water cycling in Korea where paddy rice farming is dominant in the monsoon region are quite different from those of semi-arid regions. In the calculation of water use intensity, we excluded the amount of water restored through the ground from the total agricultural water use because a large amount of water supplied to the farm was discharged into the stream or the ground water. The resultant water use intensity was 22.9% in 2001. As for water stress indicator, Korea has not defined nor monitored reference levels of minimum flow rate for rivers subject to diversion of water for irrigation. So, we calculated the water stress indicator in a different way from OECD method. The water stress indicator was calculated using data on the degree of water storage in agricultural water reservoirs because 87% of water for irrigation was taken from the agricultural water reservoirs. Water use technical efficiency was calculated as the reverse of the ratio of irrigation water to a standard water requirement of the paddy rice. The efficiency in 2001 was better than in 1990 and 1998. As for the economic efficiency for water use, we think that there are a lot of things to be taken into considerations to make a useful indicator to reflect socio-economic values of agricultural products resulted from the water use. Conclusively, site-specific, regional or meteorogical characteristics as in Korea were not considered in the calculation of water use indicators by methods suggested in OECD(Volume 3, 2001). So, it is needed to develop a new indicators for the indicators to be more widely applicable in the world.

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.79-86
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• 2018

BACKGROUND: Chinese cabbage biosynthesizes various phytochemicals including carotenoids and glucosinolates. Environmental stress has a major effect on the growth and yields of vegetables, and can significantly affect nutritionally important phytochemicals. Phytochemicals of plants are influenced by light, temperature, carbon dioxide, and growing conditions. The aim of this study was to investigate the effect of various light sources on carotenoid and glucosinolate contents in Chinese cabbage. METHODS AND RESULTS: [Experiment I] Set the control (field control, FC) on the ground. Using acrylic sunlight, experiments were set up transparency box (field transparency, FT), red box (field red, FR) and blue box (field blue, FB). [Experiment II] Set the control (chamber control, CC) in the greenhouse. Using plant growth chamber with artificial light, experiments were set up LED red (chamber red, CR), LED blue (chamber blue, CB), LED mixed red+blue (chamber red+blue, CRB) and fluorescent (chamber fluorescent, CF). After plant growth, Chinese cabbage was harvested at 110 days after sowing (DAS). The status of plants growth (leaf length, width, fresh weight etc.) was immediately investigated. Carotenoid and GSL contents were analyzed by HPLC. [Experiment I] Results documented that the ranges of total carotenoid contents were 25.39 ~ 58.80 mg/kg dry wt for lutein, 0.84~ 4.22 mg/kg dry wt for zeaxanthin, and 3.85~18.71 mg/kg dry wt for ${\beta}$-carotene. Lutein was the highest for the content and the largest for the variation as well. [Experiment II] Results documented that the ranges of total carotenoid contents were 24.66~137.96 for lutein, 2.51~20.65 for zeaxanthin, and 8.40~49.80 mg/kg dry wt for ${\beta}$-carotene. The total carotenoid contents of CR (156.62) and CB (115.90) were 1.6~2.3 times larger than the other treatments, and ${\beta}$-carotene content was about twice as high as that of the other treatments on the CR (38.74 mg/kg dry wt.). [Experiment I] Total GSL content was the highest in FT (19.76) that was higher 1.7 times than the lowest treatment ($11.39{\mu}mol/g\;dry\;wt$.). [Experiment II] The total content of GSL was highest in CRB (4.19) and lowest in CF ($2.88{\mu}mol/g\;dry\;wt$.). In the CRB, total GSL contents ($4.19{\mu}mol/g\;dry\;wt$.) was the highest. CONCLUSION: Total and individual carotenoid and GSL contents in Chinese cabbage show significant differences under different light sources. Red and blue lights contribute to significant carotenoids expression and antioxidant activity for nutrition and health benefits. These results concluded that the introduction of varying lights affected the synthesis of important nutrient compounds in Chinese cabbage. It is predicted that the application of good light source enhances the accumulation of functional compounds.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.9-15
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• 1995

This study was carried out to investigate the effects of the optimal fertilizer application levels and planting space at different seeding parts on Chinese yam from 1992 to 1993. The results obtained was as follows： The earlist day to emergence was 42~56 days at tuber section, 37~46 days at an aerial tuber, and 50~56 days at an exposed parent material. in turn. The days to emergence were delayed by increasing fertilizer application levels. In the growth of the under-ground parts, vine length was increased in a tuber section, aerial tuber, and an exposed parent material in turn. The tuber section by 60${\times}$20cm at planting space, 56-56-64 Kg/10a at fertilizer application levels was appeared to be good growth among underground parts. As planted close, the growth of tuber section was decreased. The totoal yield was appeared to be increased about 19% in a tuber section planted as 30${\times}$20cm compared with 60${\times}$20cm. In an exposed parent ma-terial, the planting space, 30${\times}$15cm, was increased 10% compared with 45${\times}$15cm, and in an aerial tuber, the planting space, 10${\times}$10cm, was increased about 10% comparing 30${\times}$10cm. Fertilization level(N-$P_2O_2K_2O$) in 56-56-64Kg/10a was increased 39 to 47% comparing 28-28-32 Kg/10a. And the heavy dressing and the close planting space were appeared to be produced the highest yield. In considering commercial quality, the optimal combination between seeding parts and planting space is recommended to improve commercial qualities and high yield.

• Journal of Korean Academy of Nursing
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• v.3 no.3
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• pp.78-96
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• 1973

This study of 855 clinical nurses was conducted using a questionnaire that include tour different scales; the motives of determining their profession, the attitudes toward their profession, the general items, and desire and expectation to their profession and society. The data were analyzed by Chi-Square Test and Percentage. The results of this study included Hypothesis are as follows; The respondents were 855 (78.6%) among 1088 clinical nurses who were employed by General of Educational hospitals through the city of Seoul, Pusan, Taegu, Daejun, Kwangju, and Wonju. 1) a. In the Age Distribution, the majority of respondents were under the age of 30yrs(88.2%) and the minority were above 31yrs(11.2%), and the preponderance of the majority to minority(9:1) was noted. In compared with area, a group above 31yrs old in Seoul (6.9%) was lower than other area (16.3%). b. The types of Educational background were 16.3% in Voc.Tr. School, 66.5% in Diploma and 17.1% in Degree.146 clinical nurses were from the Degree course, and 142 (97.3%) CN among those of them were occupied around Seoul and 4(2.7%) around other area. c. In the Marital Status,71,5% were the unmarried and 28.5% were the married. And compared with the area was 20.4% in Seoul and 41.4% in other area. d. Most common Length of Clinical Experience after graduation was under tile 2yrs (55.4%), 3yrs(14.2%, and 4yrs (6.2%). In compared with area, Seoul (15.3%) was lower than other area (38.1%) above 5yrs of clinical experience, and the preponderance of tile other area to Seoul as 2.5: I was noted. 2) a. Hypothesis 1 was significant relation between the types of Educational Background of the CN and their motives for selection of Nursing, P-value was below 0.01. b. There was a significance on hypothesis 2 (P＜0.01): that was relation between their motives for selection of clinical nursing field after their graduation and the area which they were employed. c. Hypothesis 4 was accepted as significant relation between the level of satisfaction of their clinical experience after their graduation and the types of educational back ground, P-value was below 0.01. d. There was a significance on hypothesis 5(P＜0.01) that was relation between the CN's response about the orientation program and the area which they were employed. e. Hypothesis 6 was retained as significant relation between the area and inservice educational programme of their employed hospital was practising or not. P-value was 0.01. f. Hypothesis 7 was retained as significant relation between the area and the CN's response about the inservice educational programme of their employed. P-value was below 0.01. g. There was a significance on hypothesis 8 (P<0.0l) that was relation between the CN's experience on attending the professional meeting and the area. h. Hypothesis 10 was accepted as significant relation between the response about the present licence system and their educational background. p-value was below 0.01. i. There was a significance on hypothesis 11 (P fO.01) that was relation between the carrying out the regular and delivery vacation and the area. J. Hypothesis 12 was accepted as significant relation between the CN's consideration of the lack of leisure and their marital status. p-value was below 0.01' k. There was a significance on hypothesis 13 (P <0.01) that was relation between the CN's response about their salary and their marital status. l. Hypothesis 14 was significant relation between the most difficulties of CN during their working and the hospital which they were employed. p-value was below 0.01.

• Journal of the Korean Geotechnical Society
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• v.35 no.11
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• pp.111-119
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• 2019

The high-speed railway system is mainly composed of tunnel, bridge, and viaduct to meet the straightness needed for keeping the high speed up to 400 km/s. Seismic fragility for the high-speed railway infrastructure can be assessed as two ways: one way is studying each element of infrastructure analytically or numerically, but it requires lots of research efforts due to wide range of railway system. On the other hand, empirical method can be used to access the fragility of an entire system efficiently, which requires case history data. In this study, we collect the 2004 M_W 6.6 Niigata earthquake case history data to develop empirical seismic fragility function for a railway system. Five types of intensity measures (IMs) and damage levels are assigned to all segments of target system for which the unit length is 200 m. From statistical analysis, probability of exceedance for a certain damage level (DL) is calculated as a function of IM. For those probability data points, log-normal CDF is fitted using MLE method, which forms fragility function for each damage level of exceedance. Evaluating fragility functions calculated, we observe that T=3.0 spectral acceleration (SA_T3.0) is superior to other IMs, which has lower standard deviation of log-normal CDF and low error of the fit. This indicates that long-period ground motion has more impacts on railway infrastructure system such as tunnel and bridge. It is observed that when SA_T3.0 = 0.1 g, P(DL>1) = 2%, and SA_T3.0 = 0.2 g, P(DL>1) = 23.9%.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.219-226
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• 2015

The objective of this research was to investigate the influence of various root media on the growth of mother and daughter plants during propagation and early yield after transplanting of 'Seolhyang' strawberry. To achieve this, daughter plants were fixed to connected small pots that contained expanded rice-hull (ERH), a strawberry-specialized commercial medium (SSCM), soil mother materials (SMM), or loamy sand (LS). Then, growth of daughter plants in above- and below-ground tissue as well as early yield after transplanting to plastic house soil were investigated. The growth of daughter plants in terms of plant height, leaf area and fresh weight were the highest in the SSCM treatment. Root growth in terms of the amount of primary roots and root dry weight were the highest in the treatments of ERH and SMM and the lowest in that of SSCM, among treatments tested. The ERH treatment also showed the highest values among treatments in root length, surface area and volume when roots with 0 to 0.4 mm in diameter were investigated. The flower bud differentiation of daughter plants began on Sept. 3 in the ERH treatments, earlier than the SMM (Sept. 5) and in SSCM (Sept. 7) treatments. The tissue N contents of daughter plants were in the range of 1.41 to 1.55% in all treatments, and no significant differences were observed among treatments. This indicates that the low moisture retention capacity of ERH and water stress, rather than tissue N contents, promote the flower differentiation of daughter plants. In the evaluation of early yield after transplant, the ERH treatment of showed the highest yield in the period from November to December, reaching 667 g fruit weight per 10 plants. The yields per 10 plants in the other treatments were 581 g in SMM, 475 g in SSCM and 295 g in LS. Above results imply that the various root media have different effects on the growth of daughter plants as well as flower bud differentiation. Therefore, improvement in early yield after transplant can be achieved through selection of proper root medium for daughter plant propagation.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1230-1236
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• 2012

To verify that the electrokinetic remediation is effective for decreasing salinity of fields of the plastic-film house, field tests for physical property, chemical property, and crop productivity of soils have been conducted. The abridged result of those tests is as follows. In the EK treatment, the electrokinetic remediation has been treated at the constant voltage (about 0.8 V $cm^{-1}$) for fields of the farm household. At this time, an alternating current (AC) 220 V of the farm household was transformed a direct current. The HSCI (High Silicon Cast Iron) that the length of the stick for a cation is 20cm, and the Fe Plate for an anion have been spread out on the ground. As the PVC pipe that is 10 cm in diameter was laid in the bottom of soils, cations descend on the cathode were discharged together. For soil physical properties according to the EK treatment, the destruction effect of soil aggregate was large, and the infiltration rate of water was increased. However, variations of bulk density and porosity were not considerable. Meanwhile, in chemical properties of soils, principal ions of such as EC, $NO_3{^-}$-N, $K^+$, and $Na^+$ were better rapidly reduced in the EK treated control plot than in the untreated control plot. And properties such as pH, $P_2O_5$ and $Ca^{2+}$ had a small impact on the EK. For cropping season of crop cultivation according to the EK treatment, decreasing rates of chemical properties of soils were as follows; $NO_3{^-}$-N 78.3% > $K^+$ 72.3% > EC 71.6% $$\geq_-$$ $Na^+$ 71.5% > $Mg^{2+}$ 36.8%. As results of comparing the experimental plot that EK was treated before crop cultivation with it that EK was treated during crop cultivation, the decreasing effect of chemical properties was higher in the case that EK was treated during crop cultivation. After the EK treatment, treatment effects were distinct for $NO_3{^-}$-N and EC that a decrease of nutrients is clear. However, because the lasting effect of decreasing salinity were not distinct for the single EK treatment, fertilization for soil testing was desirable carrying on testing for chemical properties of soils after EK treatments more than two times. In the growth of cabbages according to the EK treatment, the rate of yield increase was 225.5% for the primary treatment, 181.0% for the secondary treatment, and 124.2% for third treatment compared with the untreated control plot. The yield was increased by a factor of 130.0% for the hot pepper at the primary treatment (Apr. 2011), 248.1% for the lettuce at the secondary treatment (Nov.2011), and 125.4% for the young radish at the third treatment (Jul. 2012). In conclusion, the effect of yield increase was accepted officially for all announced crops.

• Asian Journal of Turfgrass Science
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• v.21 no.1
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• pp.9-21
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• 2007

Research was initiated to examine establishment efficiency of zoysiagrass by plugging. Zoysiagrass is known to be a slowly establishing turfgrass species. Properly-treated zoysiagrass seed can speed up the establishment rate, while initial irrigation practice is intensively required after seeding. A planting method with small plugs($2.5{\times}2.5cm$) from seeding can overcome initial watering requirement. Establishment speed, however, can vary with planting dates, planting spaces, and plastic film cover in early stage. Establishment characteristics were investigated for two years by planting dates that were April 5, May 18, July 13, August 24 and October 29 in 2004 and April 6 in 2005. They were also compared with three different spaces($20{\times}20,\;25{\times}25,\;and\;30{\times}30cm$) and three different fertilizer levels(15, 30, and $45g\;N{\cdot}m^{-2}$). Ground coverage reached to 90% in plugs of 'Zenith' zoysiagrass planted on April 5. It increased suddenly in period of July to August, resulting in about 50% of full establishment rate. Establishment rates were significantly faster over 9% in plugs spaced at $20{\times}25cm$ than in those at $30{\times}30cm$. No significant differences were observed on the stolen number and stolen length in the study. Survival rate in zoysiagrass plug was over 90% at all plantings. These results demonstrated that zoysiagrass establishment using small plug from seeding is considered to be a safe and efficient method.

• Journal of Korean Society of Forest Science
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• v.24 no.1
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• pp.1-24
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• 1974

A national programme of erosion control for soil and water conservation needs to be based on factual information about rates and quantities of soil erosion and of water runoff. The best and simplest way of reducing sedimentation pollution is to prevent or control the erosion at its sources. Steeply sloping earth banks are liable to both surface erosion and land-slides and the key to the control of these form of erosion lies with drainages and dense vegetation establishment including surface mulching on the slopes. Micro-plots having $1.6m^2$ (1 metre in width and 1.6 metres in slope length, and 1:1.2 in gradient) of banking slopes on the coarse sand soil are used to establish the order of magnititude of the difference in controlling of soil erosion and water runoff, and in potentiality of execution in consideration of the values of landscapes, performed on the 2 repetetions of six-experiment plots consisted of five surface mulches including seedings and one bare slope as a control treatment. The main results obtained may be summarized as follows: 1. The significant difference is realized in the quantities of soil erosion between the measures of six treatments. 2. Excepting the differences between treatment III and VI, the significant difference is realized in the rate of surface runoff between each treatment measures. 3. Both measures of treatment II and IV are recognized as the most effective measures in controlling the soil erosion and water runoff and also in establishing the ground vegetation. (Treatment II is a measures of the coarse straw-mat mulchings on the micro-strip seedings, Treatment IV is a measures of the "SPRAY-ON method" on the micro-strip seedings). In consideration of the potentiality of execution as well as the value of landscapes, the measures of treatment II could be recommendable for establishing the vegetation cover on the denuded gentle slopes in hillsides while the measures of treatment IV could be suitable for accelerating the establishment of vegetation on steeply sloping earth banks and cuts.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.283-290
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• 2017

In this study, the method to attach plastic film on the side vent from inside of greenhouse for the entire length was developed as the way to make crops less stressful while uniformly getting outside air into the greenhouse when ventilating using roof ventilation fans at single-span plastic greenhouse for oriental melon in a low-temperature period. The plastic film was installed from ground to 10cm below from the height where side vent is fully opened. In order to verify that the improved side vent can improve greenhouse environment and fruit yield, it was compared with the control plot of conventional side vent. Both greenhouses were not ventilated until February 25th, 2017. Air temperature in both greenhouses exceeded $40^{\circ}C$ in mid February. Therefore, it is judged that the greenhouse should be ventilated from mid February. Air temperature in the control plot exceeded $30^{\circ}C$ from late April. Therefore, it is judged that the plastic film attached to the inside of side vent should be removed in late April, or in early May at the latest. Soil temperature in the treatment plot in the mid Aril exceeded $20^{\circ}C$, which is suitable for growth, while that in the control plot was still below $20^{\circ}C$. Soil temperature in the control plot finally exceeded $20^{\circ}C$ in late April. The consumption of electricity was 47.2 kWh in the treatment plot, and 48.3 kWh in the control plot, which was no significant difference. The marketable yield of oriental melon in the treatment plot was 5,094kg, which was 23.9% more than that in the control plot, 4,113kg. The marketable fruit ratio was 73.5% in the treatment plot, and that in the control plot was 73.9%, which was no significant difference.