• Korean Journal of Soil Science and Fertilizer
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• v.22 no.1
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• pp.61-66
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• 1989

Plants were exposed to different sub-optimal growth temperature regimes for hardening or sprayed with abscisic acid (ABA) before being placed at $10^{\circ}C$ for three days. Comparisons were made with non-treated plants for plant survival, photosynthetic activities and fatty acids composition of phospholipids. The level of endogenous ABA of the hardened seedlings was compared with that in control and ABA sprayed-seedlings. The results of the above experiment were summarized as follows: 1. Compared to non-treated plants, the hardening and ABA treatment resulted in higher plant survival rate and better seedling growth following earlier transplanting. The low temperature hardening which gradually increased the duration of the low temperature treatment at 2-day intervals was more effective than the controled temperature hardening which gradually decreased the temperature from $25^{\circ}C$ to $20^{\circ}C$ and $15^{\circ}C$. 2. The photosynthetic activities of rice leaves after 3-day exposure to $10^{\circ}C$ were higher in hardened and ABA sprayed seedlings than in non-treated plants. The root activities after low temperature treatment were also higher in hardened and ABA sprayed seedlings than in control. 3. Fatty acids of phospholipids in rice plants such as stearic acid and oleic acid were decreased and the highly unsaturated fatty acids, linoleic acid and lenolenic acid were increased by hardening or ABA treatments. It is assumed that the increase of cold tolerance in these plants was due to the higher ratio of unsaturated to saturated fatty acids. Respectively, the ratio was 1.86, 1.97 and 1.80 in plants given controled temperature hardening, the low temperature hardening and ABA treatments. While in control plants, it was 1.17. 4. ABA content in rice seedling given the low temperature hardening treatment was 67.2 ng/g F.W which was approximately twice that of non-treated control, which was 33.9 ng/f F. W., in contrast, the ABA content of the ABA treated seedlings was 91.7 ng/g F. W.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.1
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• pp.1-7
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• 2001

Total upland area for cultivating the vegetable crops in the Alpine soils of Northeastern South Korea has been extending its limit to meet the increasing demand of vegetable food in recent decades. About 70% of these alpine soils are located in over 7% of the slope and most of vegetable crops have been cultivated intensively without practicing the best management systems. Thus, soil erosion and continuous cropping system have degenerated the soil fertility and shown detrimental effects on water quality. We initiated an intensive and extensive investigation to characterize the fertility problems encountered in these uplands. Objectives of this paper were to characterize the fertility status in the Alpine soils cultivated with vegetable crops for many years and to provide the recommendations for adequate soil management measures including fertilization and erosion control. Soils in general have good drainage with textural classes of loam or sandy loam. Their topographical characteristics tended to lead them to shallow plow layers, and the steepness of the terrain created erosion hazard. Of the soils examined, about 11% of uplands over 30% gradient was found in need of an urgent reforestation. A high content of gravel and firm hardness of soil attributed to inhibit the utilization of farm machinery and plant-root development. The average soil pH 5.6 was slightly low relative to pH 5.70 of the national average. Organic matter content was high compared with 2.0% of national average, but decreased with the prolonged cultivation periods. Available $P_2O_5$ concentration was unusually high due to the consequence of over dose application with chemical and organic fertilizers. Exchangeable cations as Ca, Mg, and K were appeared to be decreased in these regions with prolonging the cultivation periods. There were no significant differences in cation exchange capacity (CEC) and electrical conductivity (EC) among locations. Heavy metal contents were mostly lower than the threshold of danger level designated by Soil Environment Conservation Law of South Korea. Results indicated that a proper countermeasure and the best management practice should be immediately implemented to conserve the top soil and fertility in the Alpine regions.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.16-24
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• 1998

To determine the optimum application of fertilizers for the cultivation of Chinese cabbage in plastic film house, twenty soils which contain different salts contents were taken from 4 different area of plastic film house cultivation, Youngdong. Boeun county, Cheongweon county, and Cheongju city. The dry weight and the amount of N. P, and K uptakes of Chinese cabbage in the plot of no fertilization were considered as the factors representing the fertility of the soil. And a difference of dry weight and the amounts of N, P, and K uptakes of plants between the plot of fertilization and no fertilization were considered as the factors representing the total effect of fertilizer and fertilizer N, P, and K effects. respectively. These factors of soil fertility and fertilizer effects were estimated by correlation and regression with soil tests in order to find the critical levels and recommended method for optimum fertilization of Chinese cabbage. Chinese cabbage transplanted in two soils, having the electrical conductivity of 9.3 and 15.2 dS/m, were not able to root due to the salts toxicity. The content of inorganic N, the electrical conductivity, and CEC were founded to have significant correlation with the factors of both the soil fertility and fertilizer effects for the cultivation of Chinese cabbage. To determine the weighting degree for the productivity and the fertilizer effects, the standardized partial regression coefficient was analyzed by regression among the factors of fertility, the fertilizer effects, and the soil tests. The coefficient for inorganic N($NH_4-N$ and $NO_3-N$) was obtained as the absolute value of 756-1871 and this value was extremely higher than those of other soil tests which was 0.07-4.11. These results suggested that the content of inorganic N is the best tests for the estimation of the productivity and the fertilizer effects for the cultivation of Chinese cabbage in plastic film house. The critical level of inorganic N($NH_4-N+NO_3-N$) estimated by Cate-Nelson split method for maximum productivity and zero point of fertilizer effect was 220 mg/kg for all the factors of estimation. These results suggested that no application of fertilizer N. P, and K is required at the critical level of inorganic N of soil. Consequently the optimum application of fertilizer N, P, and K for the cultivation of Chinese cabbage in plastic film house was possible to determine by the critical level of inorganic N of soil. The critical level of electrical conductivity was estimated as 2.8 dS/m by the same method.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.2
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• pp.108-117
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• 2005

Pharmaceutical byproduct sludge and cosmetic industry wastewater sludge can be used as a raw material of compost. Effects of three types of pharmaceutical byproduct sludge and one type of cosmetic industry wastewater sludge on soil properties and red pepper growth were investigated in a field based concrete pot ($2{\times}2m$). These sludges and pig manure ($5Mg\;ha^{-1}$, dry basis) were incorporated into the upper of loam soil 30 days prior to transplanting red pepper. Changes in soil properties and contents of heavy metals and toxic organic compounds in soil and plant were measured. And also plant growth measurement and bioassay of soil phytotoxicity were included. Contents of heavy metals were increased in the soils treated with the sludges. Plant growth in the sludge treatments were mostly inferior to that of NPK treatment, especially in early stage. Content of N in plant was lower in all sludge treatments at early and middle growth stages, and it was especially caused by characteristics and concentration of nitrogen and organic matter of sludges. Total yield of red pepper was highest in the NPK treatment and followed by pharmaceutical sludge 3, pig manure, pharmaceutical sludge 1, and pharmaceutical sludge 2, and the yield of cosmetic sludge treatment was considerably lower than others. HEM and PAHs contents in soil of cosmetic sludge treatment were $4.80mg\;kg^{-1}$ and $2,263.2{\mu}g\;kg^{-1}$, respectively. Root elongation of lettuce exposed to the water extract of soil treated with cosmetic sludge was about 20% of that found in the test with soil extract of non fertilization treatment. At present, raw materials of compost were authorized according to the contents of organic matter, heavy metals and product processing. Toxic organic compounds analysis and bioassay would be helpful for authorization and assessment of suitability of raw materials of compost.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.688-695
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• 2011

This study was carried out for some survey about soil compaction in the multi-cropping system of paddy field. Investigated sites were 90 farmer's fields in south-eastern part of Korea. The tillage practices season was different according to cropping system of paddy; in spring for mono rice cultivation and in autumn for the multi-cropping field. The average tillage depth in investigated sites was about 25 cm, however, it is different between the farmer's tillage practices and soil characteristics. It is high correlation to tillage deep and minimum resistance of penetration. The reaching soil deep to maximum resistance of penetration was about 27 cm, and average penetration resistance of the deep is 1.8~2.0 MPa for moderately fine-textured soils and more than 3.0 MPa for moderately coarse-textured soils. The difference of penetration resistance between cultivating and compacted layer was in order to sandy loam > clayey loam > clayey, and the difference was lesser in poorly drained soils than somewhat poorly ones. In the rice mono cropping field, the maximum resistance in no-tillage for 15 years was 1.18~1.25 Mpa at 20~25 cm in soil deep, however, the resistance of field with every year tillage practices was 2.03~2.21 Mpa. In the extremely compacted sandy loam textured soils, the penetration resistance at 30 cm in soil depth was drastically reduced by the subsoil from 5.2 Mpa to 3.2 Mpa, and the watermelon root in plastic film house was deep elongated.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.717-721
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• 2011

In case of plastic film greenhouses cultivating fresh vegetables on paddy soil, soil characteristics must be considered as more important factor than any other factors. Generally after the four years of cultivation, soils tend to increase electrical conductivity value, nutrient unbalance and soil pests. As a result, degradation of agricultural products occurred, therefore it is necessary to improve soil conditions. In this study, yield and economic cost of cucumber were analyzed. The best soil conditions for cucumber cultivation were alluvial or valley in soil topology, moderately or poorly drainage in soil drainage classes, coarse loamy soil in texture. In addition, rich-sunlight and-deep groundwater would be proper for the cucumber cultivation. Good environmental managements of plastic film greenhouse were as follows. The temperature needed to be adjusted three times. The optimal daytime temperature could be $22{\sim}28^{\circ}C$, the one from 12 until night could be $14{\sim}15^{\circ}C$, and the temperature from 24 to sunrise could be $10{\sim}12^{\circ}C$. During plant growth period, soil moisture content was as low as 10~15%, and it needed to be maintained as 15~20% during reproductive growth period. To control pests, catch crop cultivation and solar treatment were carried out, after those EC was reduced and the root-knot nematode was controled too. Cucumber yield from the plot with improved soil managements increased to $158.4Mg\;ha^{-1}$, but plot with successive cropping injury yielded $140.3Mg\;ha^{-1}$. The income from the plot with improved soil managements was 215,676 thousand won $ha^{-1}$, the plot with successive cropping injury was 131,649 thousand won $ha^{-1}$. Income rate of each plot was 51.8% and 38.4%, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1042-1047
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• 2011

Copper and Zinc are essential trace elements for all living organisms. When presenting in excess amount in soils, however they can be toxic to plants. In order to examine the transfer of Cu and Zn from soils to plants and to predict their contents in plants using soil factors, we investigated total and mobile contents of Cu and Zn in soils and their uptake by lettuce (Lactuca sativa L.) in plastic film houses. Total Cu and Zn contents in soils were $17.5{\sim}65.9mg\;kg^{-1}$ (mean: $39.3mg\;kg^{-1}$) and $63.2{\sim}200mg\;kg^{-1}$ (mean: $137mg\;kg^{-1}$), respectively. Mobile Cu and Zn contents in soils were $(0.04){\sim}0.55mg\;kg^{-1}$ (mean: $0.18mg\;kg^{-1}$) and $(0.05){\sim}2.62mg\;kg^{-1}$ (mean: $0.47mg\;kg^{-1}$), respectively. Soil pH ranged from 5.4 to 7.3 and OM from 24.1 to $59.9g\;kg^{-1}$. Mean Cu contents in leaves and roots of lettuce were 9.20 and $17.2mg\;kg^{-1}$, respectively which showed that Cu was accumulated mainly in root parts of lettuce and not easily transported to leaves. In contrast, Zn was fairly evenly distributed in leaves and roots with mean values of 54.5 and $56.7mg\;kg^{-1}$, indicating relative high mobility of Zn in lettuce. Transfer factors of Cu and Zn from soil total contents to roots and leaves of lettuce ($TFS_tR$ and $TFS_tL$) were between 0.1 and 1, while transfer factors from soil mobile contents to roots and leaves ($TFS_mR$ and $TFS_mL$) were between 10 and 1000. Transfer factors of Zn were higher than those of Cu, showing Zn was more easily absorbed by plants than Cu. Cu and Zn uptake was stronger influenced by soil pH and mobile contents than total contents and OM and could be significantly described by multiple regression equations including soil pH and soil mobile contents as variables.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.447-453
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• 2007

With a broad objective for the development of microbial based fertilizers, a total of 373 strains were isolated from rhizoplane and rhizosphere of pepper, tomato, lettuce, pasture, and grass. The efficacy of the isolates to augument overall plant growth was evaluated. After screening for their plant growth promotion and antagonistic properties in vitro efficient strains were further selected. The most efficient strains was characterized by 16S rRNA gene sequences and biochemical techniques and was designated as Bacillus subtilis S37-2. The strains facilitated plant growth and inhibited the plant phathogenic fungi such as Fusarium oxysporum (KACC 40037, Rhizoctonia solani (KACC 40140), and Sclerotinia sclerotiorum (KACC 40457). Pot based bioassay using lettuce as test plant was conducted by inoculating suspension ($10^5$ to $10^8cells\;mL^{-1}$) of B. subtilis S37-2 to the rhizosphere of lettuce cultivated in soil pots. Compared with non-inoculated pots, marked increase in leaf (42.3%) and root mass (48.7%) was observed in the inoculation group where the 50ml of cell mixture ($8.7{\times}10^8cells\;ml^{-1}$) was applied to the rhizosphere of letuce either once or twice. Antagonistic effects of B. subtilis S37-2 strain on S. sclerotiorum (KACC 40457) were tested. All the tested lettuce plants perished after 9 days in treatment containing only S. sclerotiorum, but only 17% of lettuce was perished in the inoculation plot. B. subtilis grew well in the TSB culture medium. The isolates grew better in yeast extracts than peptone and tryptone as nitrogen source. The growth rate was 2~4 times greater at $37^{\circ}C$ as compared with $30^{\circ}C$ incubation temperature. B. subitlis S37-2 produced $0.1{\mu}g\;ml^{-1}$ of IAA (indole 3-acetic acid) in the TSB medium containing L-tryptophan($20mg\;L^{-1}$) in 24 hours.

• Journal of Christian Education in Korea
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• v.67
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• pp.45-75
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• 2021

The purpose of this study is to explore a new paradigm for Bible didactics in the context of the contemporary times and it turns its gaze to the midrash, the old tradition of Hebrew Bible interpretation. In order for the current Bible study to be meaningful and effective in today's situation, it is an effort to connect the Bible and us well, more than educational contents or materials. The word "midrash" itself means "textual interpretation", or "study", derived from the root verb darash, which means "to seek," "to seek with care," "to enquire," "to require" forms of which appear frequently in the Hebrew Bible. Midrash means an exegesis and interpretation of the Hebrew Bible (Torah) as well as a group of works that are the result of specific interpretations of the rabbis. This rabbinical tradition provides specific interpretative guidelines dealing with the Bible. These interpretive guidelines were passed down and formed an attitude of interpreting the Bible that is still relevant today. The rabbinical interpretative guidelines in midrash lead to the discovery of the following biblical didactical meanings. First, the Bible requires an attitude of listening and learning. Second, an attitude of inquiry is needed. Third, an exploration through the empty space is essential. Fourth, it leads us to recognize the importance of mutual respect and communication. Fifth, through the Words that challenge me, the meaning of biblical teaching is discovered. These interpretation guidelines have much in common with Bibliodrama, which applies midrash to the didactic of Bible. Bibliodrama is a dramatic inquiry, where the effect of in-depth inquiry and consideration that midrash aimed at can be expected. In addition, bibliodrama is a process of communal interaction that leads to a new experience and a richer understanding of the Bible through different positions and viewpoints. Exploring the "white fire" of the Bible, we listen to what God says to us, which causes us to change and form an identity. The biblical didactical meaning found in midrash's interpretation guidelines and the biblical didactical application of midrash through the bibliodrama can be presented as a new alternative to Christian education for the past, the present and the future. This will be able to present a new paradigm for biblical didactics with the word of God living and working in the present, not the Bible of the past, which is far from our present life.

• Journal of Korea Water Resources Association
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• v.54 no.12
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• pp.1243-1254
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• 2021

For water resources operation or agricultural water management, it is important to accurately predict evapotranspiration for a long-term future over a seasonal or monthly basis. In this study, reference evapotranspiration forecast (up to 12 months in advance) was performed using statistically predicted monthly temperatures and temperature-based Hamon method for the Han River basin. First, the daily maximum and minimum temperature data for 15 meterological stations in the basin were derived by spatial-temporal downscaling the monthly temperature forecasts. The results of goodness-of-fit test for the downscaled temperature data at each site showed that the percent bias (PBIAS) ranged from 1.3 to 6.9%, the ratio of the root mean square error to the standard deviation of the observations (RSR) ranged from 0.22 to 0.27, the Nash-Sutcliffe efficiency (NSE) ranged from 0.93 to 0.95, and the Pearson correlation coefficient (r) ranged from 0.97 to 0.98 for the monthly average daily maximum temperature. And for the monthly average daily minimum temperature, PBIAS was 7.8 to 44.7%, RSR was 0.21 to 0.25, NSE was 0.94 to 0.96, and r was 0.98 to 0.99. The difference by site was not large, and the downscaled results were similar to the observations. In the results of comparing the forecasted reference evapotranspiration calculated using the downscaled data with the observed values for the entire region, PBIAS was 2.2 to 5.4%, RSR was 0.21 to 0.28, NSE was 0.92 to 0.96, and r was 0.96 to 0.98, indicating a very high fit. Due to the characteristics of the statistical models and uncertainty in the downscaling process, the predicted reference evapotranspiration may slightly deviate from the observed value in some periods when temperatures completely different from the past are observed. However, considering that it is a forecast result for the future period, it will be sufficiently useful as information for the evaluation or operation of water resources in the future.