• 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.39 no.6
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• pp.357-365
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• 2006

The investigations were conducted to find out the situation of fertilizer use and the contents of soil chemical components on summer vegetable crops at 791 farmers' upland fields located in the parts of Gangwon-do, Gyengsangbuk-do and Jeollabuk-do of alpine area. Major vegetable crops were potato, Chinese cabbage, radish, carrot, onion, and cabbage. From the location surroundings cultivated alpine vegetable crops, the orders were Gangwon-do>Gyeongsangbuk-do>Jeollabuk-do part in the sizes of a fie1d area and the height above sea level, and Jeollabuk-do>Gyeongsangbuk-do>Gangwon-do part in the slope degrees. The soil texture was of wide distribution on sandy loam soil for Gangwon-do(76%) and Jeollabuk-do part(64%), and 1oam(42%) and sandy loam soil(35%) for Gyeongsangbuk-do part. From the numbers of investigated fields, the distribution of slope degree was wider than those of height above sea level in relation to location surroundings. The upland soils of 785 fields cultivated vegetable crops were sampled at 0~15 cm of top soil before seeding or transplanting and analyzed. On an average, pH, organic matter, available phosphate and exchangeable potassium, calcium, magnesium of soil were 5.7, $27.6g\;kg^{-1}$, $765mg\;kg^{-1}$, $1.16cmol_c\;kg^{-1}$, $6.1cmol_c\;kg^{-1}$, and $1.6cmol_c\;kg^{-1}$, respectively. The average cation exchange capacity(CEC) of 120 sites in Gangwon-do part was $9.2cmol_c\;kg^{-1}$. The content of organic matter, exchangeable potassium, exchangeable calcium and exchangeable magnesium was higher, while that of available phosphate was lower with slope degrees. And the content of major chemical components in carrot soil was lower in comparison with other crop soils. The average levels of N, $P_2O_5$, $K_2O$, livestock manure and lime fertilizer of 785 Belds applied by farmers were 335, 198, 244, 12,680 and $1,750kg\;ha^{-1}$, respectively, for summer vegetable crops in alpine area. The average amounts of $N-P_2O_5-K_2O$ fertilizers applied by farmers in 785 Gelds of vegetable crops were higher 1.7~2.0-4.2~7.0-1.4~2.0 times on potato, 1.4~1.6-4.6~8.3-3.5~4.2 times on Chinese cabbage, and 1.2~1.3-4.2~7.2-3.0~3.61 times on radish than the rates of NPK fertilizers based on soil testing for each crop.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.6
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• pp.351-356
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• 2006

A long-term experiment was initiated in 1979 at Experiment Farm of Honam Agricultural Research Institute, to investigate the effects of continued use of organic matter (rice straw and compost) along with different levels of nitrogen fertilizer in rice cultivation. The soils of experimental plots is classified as Jeonbug series developed on Fluvio-marine deposits. The application rates of rice straw and compost were 5 Mg/ha/year and 10 Mg/ha/per year, respectively. The fertilizer N application rates per season were 0, 100, 150, 200, and 250 kg/ha. In 2002, after 24 years of experiment, the effect of different treatments on soil pH, characteristics soil organic matter, soil N and P were investigated. The results of the study is summarized as following. The continue use of organic matter tended to lower the soil pH, to increase organic matter and available phosphate contents. The rice straw tended to lower soil pH more than compost, while the effect of compost was greater in increasing soil organic matter and available soil P then rice straw. The application of organic matter resulted in the increase in total organic N in the soil. Such effect was greater in compost application than in rice straw application. In organic N, greatest was amino acid-N, followed by unidentifiable organic N. The least was amino sugar-N. The application of organic matter with and without nitrogen fertilizer affected the in organic fractions of P, particularly Fe-P and Al-P. The application of rice straw tended to increase Ca-P.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.923-929
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• 2010

This study was conducted to investigate the relations between soil chemical properties and Korean raspberry (Rubus coreanus Miq.) growth. Soils were collected from 54 sampling sites in 1 to 6 years old Korean raspberry cultivation fields (RCFs) at Gochang-gun, Jeollabuk-Do, Korea. In RCF with two to six years old plants, soil pH and exchangeable $Ca^{2+}$ and $Mg^{2+}$ contents were higher at the leaf-emergence time, but EC, available phosphorus content, CEC, and total nitrogen content were higher at the harvesting time; especially at the harvesting time, the content of available phosphorus in the RCF with 3~6 years old plants were at least three times higher than in the RCF with 2 years old plants. Water-soluble anions ($Cl^-$, ${NO_3}^-$, ${PO_4}^{2-}$, and ${SO_4}^{2-}$) in the RCF were also measured. The contents of ${NO_3}^-$ and ${SO_4}^{2-}$ were always higher in the RCF with older plants than in the RCF with younger plants, which were not affected by sampling time and sampling locations (rhizosphere and non-rhizosphere sites). However, soils collected from non-rhizosphere at the leaf-emergence time contained higher ${PO_4}^{2-}$ content, but $Cl^-$ content was higher in the soils collected from rhizosphere at the harvesting time. In general, soils in the RCFs contained excess amounts of inorganic nutrients such as available phosphorus and exchangeable $K^+$. Thus, optimal levels of soil properties for Korean raspberry cultivation should be reconsidered.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.852-857
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• 2010

This study was performed to explore the effect of the clay mineral illite on the improvement of bed soil and plant growth. Red pepper (Capsicum annuum L.) was used as a model vegetable crop. The experiment was performed during the whole six weeks in the glass house of the Chungbuk National University. Its seedlings were cultivated in the bed soil normally used for horticultural purpose. Of the seedlings cultured, the healthy and regular size of seed were selected and cultivated in the pots. They were treated with two forms of illite, particulate (PA) and powder (PW), at the following application rates: standard application[P1 (PA1, PW1), 1:20 (w/w)], two times[P2 (PA2, PW2), 1:10 (w/w)], and four times[P4 (PA4, PW4), 1:5 (w/w)] of standard application. Untreatment (P0) was used as a control pot. At six weeks of cultivation, their growth lengths were correspondingly increased as the application rate was increased ranging from P0, P1, P2, and to P4. Their growth length was a little greater on the application of powder illite (PW) than on the particulate illite (PA). Based on the plant analysis for the root, leaf, stem of red pepper, the uptake amounts of K, Ca, and Mg, were correspondingly increased, as the application rate was increased ranging from P0, P1, P2, and to P4, respectively. At the same application rate, their amounts taken up in the respective parts were higher on the application of PW illite than on the PA one. Especially the amounts of Ca and Mg were higher in the stem, leaf than root. Consequently, it appears that the illite treatment, especially, PW form of illite, enhance the growth of red pepper in the glass house during the whole six weeks of experiment.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.6
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• pp.435-441
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• 2007

Ground-based optical sensing over the crop canopy provides information on the mass of plant body which reflects the light, as well as crop nitrogen content which is closely related to the greenness of plant leaves. This method has the merits of being non-destructive real-time based, and thus can be conveniently used for decision making on application of nitrogen fertilizers for crops standing in fields. In the present study relationships among leaf nitrogen content of rice canopy, crop growth status, and Normalized Difference Vegetation Index (NDVI) values were investigated. We measured Green normalized difference vegetation index($gNDVI=({\rho}0.80{\mu}m-{\rho}0.55{\mu}m)/({\rho}0.80{\mu}m+{\rho}0.55{\mu}m)$) and NDVI($({\rho}0.80{\mu}m-{\rho}0.68{\mu}m)/({\rho}0.80{\mu}m+{\rho}0.68{\mu}m)$) were measured by using two different active sensors (Greenseeker, NTech Inc. USA). The study was conducted in the years 2005-06 during the rice growing season at the experimental plots of National Institute of Agricultural Science and Technology located at Suwon, Korea. The experiments carried out with randomized complete block design with the application of four levels of nitrogen fertilizers (0, 70, 100, 130kg N/ha) and same amount of phosphorous and potassium content of the fertilizers. gNDVI and rNDVI increased as growth advanced and reached to maximum values at around early August, G(NDVI) were a decrease in values of observed with the crop maturation. gNDVI values and leaf nitrogen content were highly correlated at early July in 2005 and 2006. On the basis of this finding we attempted to estimate the leaf N contents using gNDVI data obtained in 2005 and 2006. The determination coefficients of the linear model by gNDVI in the years 2005 and 2006 were 0.88 and 0.94, respectively. The measured and estimated leaf N contents using gNDVI values showed good agreement ($R^2=0.86^{***}$). Results from this study show that gNDVI values represent a significant positive correlation with leaf N contents and can be used to estimate leaf N before the panicle formation stage. gNDVI appeared to be a very effective parameter to estimate leaf N content the rice canopy.

• Korean Journal of Psychosomatic Medicine
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• v.24 no.2
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• pp.227-235
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• 2016

Objectives : The aims of this study were to know the frequency of cognitive dysfunction among patients with autoimmune thyroid disorders, and to reveal influencing factors on it, especially to clarify association with autoimmune thyroid antibodies. Methods : From sixty-five female patients with autoimmune thyroid disorders, demographic data were obtained by structured interview. Their cognitive funtions were measured using the MMSE-K and the MoCA-K tests. Depression was evaluated by the K-HDRS. Results : 1) Among patients with autoimmune thyroid disorders, 7.69% of them were below 24 on the MMSE-K, while 10.77% were below 22 on the MoCA-K. The frequency of cognitive deficit was not significantly different according to having positivity to antimicrosomal antibodies or not. 2) The antimicrosomal antibody-positive patients had significantly higher antithyroglobulin antibody titers, antimicrosomal antibody titers, and TSH concentration, while had significantly lower free T4 levels(p<0.05, respectively). 3) The total scores of the MMSE-K and the MoCA-K had significant correlation with age, marital status, antithyroglobulin antibody titers and K-HDRS(p<0.05, respectively). 4) The regression analysis revealed that variables such as age, education, autoimmune thyroid antibodies, thyroid function and depression did not influence on cognitive function of patients with autoimmune thyroid disorders. Conclusions : Our results could not support that cognitive function of patients with autoimmune thyroid disorders had correlation with autoimmune thyroid antibodies.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.451-464
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• 2022

The high-level nuclear waste repository is a deep geological disposal system exposed to complex environmental conditions such as high temperature, radiation, and ground-water due to handling spent nuclear fuel. Continuous exposure can lead to cracking and deterioration of the structure over time. On the other hand, the high-level nuclear waste repository requires an ultra-long life expectancy. Thus long-term structural health monitoring is essential. Various sensors such as an accelerometer, earth pressure gauge, and displacement meter can be used to monitor the health of a structure, and a piezoelectric sensor is generally used. Therefore, it is necessary to develop a highly durable sensor based on the durability assessment of the piezoelectric sensor. This study designed an accelerated life test for durability assessment and life prediction of the piezoelectric sensor. Based on the literature review, the number of accelerated stress levels for a single stress factor, and the number of samples for each level were selected. The failure mode and mechanism of the piezoelectric sensor that can occur in the environmental conditions of the high-level waste repository were analyzed. In addition, two methods were proposed to investigate the maximum harsh condition for the temperature stress factor. The reliable operating limit of the piezoelectric sensor was derived, and a reasonable accelerated stress level was set for the accelerated life test. The suggested methods contain economical and practical ideas and can be widely used in designing accelerated life tests of piezoelectric sensors.

• Korean Journal of Environmental Agriculture
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• v.40 no.4
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• pp.353-358
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• 2021

BACKGROUND: Prochloraz has been widely used as an imidazole fungicide on fruits and vegetables in Korea. Analytical approaches to evaluate prochloraz residues in herbal medicine are required for their safety management. In this study, we developed a GC-ECD method for quantitative determination of prochloraz in Platycodi Radix. The metabolite 2,4,6-trichlorophenol (2,4,6-T) was used as a target compound to evaluate total prochloraz residues as it is categorized to a representative residue definition of prochloraz. All residues containing 2,4,6-T were converted to 2,4,6-T and subjected to GC-ECD. METHODS AND RESULTS: In order to verify the applicability, the method was optimized for determining prochloraz and it metabolite 2,4,6-T in Platycodi Radix. Prochloraz and its metabolite 2,4,6-T residuals were extracted using acetone. The extract was diluted with and partitioned directly into dichloromethane to remove polar co-extractives in the aqueous phase. The extract was decomposed to 2,4,6-T, and then the partitioned ion-associate was finally purified by optimized aminopropyl solid-phase extraction (SPE). The limits of quantitation of the method (MLOQs) were 0.04 mg/kg and 0.02 mg/kg, respectively for prochloraz and 2,4,6-T, considering the maximum residue level (MRL) of prochloraz as 0.05 mg/kg in Platycodi Radix. Recovery tests were carried out at two levels of concentration (MLOQ, 10 MLOQ) and resulted in good recoveries (82.1-89.7%). Good reproducibilities were obtained (coefficient of variation < 2.8%), and the linearities of calibration curves were reasonable (r² > 0.9986) in the range of 0.005-0.5 ㎍/mL. CONCLUSION(S): The method developed in this study was successfully validated to meet the guidelines required for quantitative determination of pesticides in herbal medicine. Thus, the method could be useful to monitor prochloraz institutionally in herbal medicine.

• Science of Emotion and Sensibility
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• v.24 no.3
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• pp.3-16
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• 2021

Studies have found that people with higher social status pay little attention to other people's emotions and facial expressions. However, only a few studies have made similar observations on adolescents with high cyberspace social status. Therefore, this study sought to identify how adolescents with different online game character social statuses interpreted the smile emoticons in negative and positive situations, that is, did they perceive the emoticon to be positive (smile, encouragement, and consolation) or negative (derision, ridicule, and sarcasm). In Experiment 1, the participants were separated into three groups; those who had a lower than global average online game character status, those who had the same as the global average, and those who had higher than the global average. The participants were then asked to judge the meaning of the smile emoticon received in various positive or negative situations. In Experiment 2, the game character levels of the participants were set to be either higher or lower than the others' characters, and they were again asked to judge the meaning of the smile emoticon received in the positive or negative situations. In Experiment 3, the participants were separated into four groups; lower level than the average game character status (no information on the level of acquaintance's game character), lower than the average but higher than the character of the other, higher than the average status (no information on the other's character level), and higher than the average but lower than the character of the other, and asked to judge the meaning of the smile emoticon in positive or negative situations. It was found that when participants had a lower-level character compared to the average, had a lower-level character than the other, and had higher than the average but lower than the other's character, they interpreted the smile emoticon as derision, ridicule, or sarcasm. However, participants with higher level characters, higher than that of the other, and lower than the average but higher than the other interpreted the emoticon as a smile or consolation. This study was significant because it demonstrated the impact of an adolescent's social cyberspace status on their online communication.