• Journal of the Korean Society of Industry Convergence
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• v.20 no.5
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• pp.395-404
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• 2017

Cultivating soybeans in rice paddy field reduces labor costs and increases the yield. Soybeans, however, are highly susceptible to excessive soil water in paddy field. Controlled drainage system can adjust groundwater level (GWL) and control soil moisture content, resulting in improvement soil environments for optimum crop growth. The objective of this study was to fit the soybean growth data (canopy height and stem diameter) using Gompertz model and Logistic model at different GWL and validate those models. The soybean, Daewon cultivar, was grown on the lysimeters controlled GWL (20cm and 40cm). The soil textures were silt loam and sandy loam. The canopy height and stem diameter were measured from the 20th days after seeding until harvest. The Gompertz and Logistic models were fitted with the growth data and each growth rate and maximum growth value was estimated. At the canopy height, the $R_2$ and RMSE were 0.99 and 1.58 in Gompertz model and 0.99 and 1.33 in Logistic model, respectively. The large discrepancy was shown in full maturity stage (R8), where plants have shed substantial amount of leaves. Regardless of soil texture, the maximum growth values at 40cm GWL were greater than the value at 20cm GWL. The growth rates were larger at silt loam. At the stem diameter, the $R_2$ and RMSE were 0.96 and 0.27 in Gompertz model and 0.96 and 0.26 in Logistic model, respectively. Unlike the canopy height, the stem diameter in R8 stage didn't decrease significantly. At both GWLs, the maximum growth values and the growth rates at silt loam were all larger than the values at sandy loam. In conclusion, Gompertz model and Logistic model both well fit the canopy heights and stem diameters of soybeans. These growth models can provide invaluable information for the development of precision water management system.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.2
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• pp.81-92
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• 2017

Recently, agricultural lands have decreased sharply, which was caused by huge housing site, urbanization, land consolidation, and road construction etc. In particular, Yangju city near Seoul city has the most severe land use change in Korea. Therefore, we analyzed changes of land use, soil properties, and soil information in order to provide the basic soil information and soil management practices in this city. The area of crop cultivated land in Korea (2015) reduced by 12,090 ha compared to ones from the previous year (2014). The paddy field decreased by 25,421 ha but, upland field increased by 13,331 ha. One of the reasons for the reduction of the paddy field was converting paddy field to upland (20,916 ha) > others (3,056) > building (2,571) > public facilities (847) > idle land (217). But, reasons for increase of upland field were switching paddy to upland (20,916 ha) > land developed (634). The main reason of converting paddy field to upland was changing from rice to more profitable speciality crops or pulses. The cropland area (paddy fields, upland, orchard) of Yangju city reduced by 1,412 ha (2015/2014). The ratio of cropland area in each city reduced by 22.9% dramatically compared 2015 to 1999. The paddy fields located in alluvial plains in Yangju city were changed into upland or green house. The drainage classes of soil have been deteriorated because the flows of water were intercepted by road construction and other disturbance to water flows. In particular, paddy fields have been changed to not only upland, orchard, greenhouse cultivation but also to fallow and soil dressing on paddy in Yangju city. To analyze result of soil survey of Yangju city, 858 soil codes (soil phases) were used and the area was 105.17ha. The number of soil series increased from 60 to 65, and that of soil phase increased from 105 to 124. The largest increased area was Noegog soil series. 125.7ha of Neogog soil series was incorporated from the existing Sachon, Yecheon and Eungog soil series. The soil suitability class of paddy field in Ogjung huge housing site of Yangju city was the 4th grade for 32.6% of the area. The soil suitability classes of upland were 2nd and 3rd grade for 72.4% of the area. Farm land with high quality should be conserved by related law.

• Analytical Science and Technology
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• v.7 no.2
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• pp.237-243
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• 1994

The stability of W/O emulsions (milk fat : water=4 : 1, w/w) containing various emulsifiers was compared to determine the effect of different chemical types of emulsifiers in relation to the change of HLB value caused by emulsifier type and the influence of single vs. binary emulsifier systems. These variables were compared at emulsifier HLB values of 0.5~16.7 and at emulsifier concentrations of 1.0~3.0%(w/w). Eleven emulsifiers used as 11 different single mixtures and 16 different binary mixtures were evaluated in W/O type emulsion systems containing 20.0%(w/w) of water in milk fat. This W/O emulsion was stable (more than 90.0 of ESI value) in the range of low value of emulsifier HLB (less than 4.7 of HLB value). All the ESI values of binary emulsifier systems were higher than those of single emulsifier systems. But, the influence pattern of emulsifier HLB on this emulsion stability in single emulsifier systems was very similar to the trend in binary emulsifier systems.

• The Korean Journal of Pesticide Science
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• v.20 no.3
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• pp.236-246
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• 2016

The aim of this study was to develop an analytical method for the determination of pyribencarb and its metabolite KIE-9749 in agricultural commodities. The experiment was performed with a range of concentrations $0.05{\sim}2.5{\mu}g/g$ in apple, green pepper, potato, hulled rice, soybean, pear, peach, grape and cucumber. Each samples were extracted with acetone and cleaned by dichloromethane/saline water partition and purified with Florisil solid phase extraction (SPE) cartridge and aminopropyl SPE cartridge. Pyribencarb and KIE-9749 were separated and quantified by HPLC/UVD at 265nm using acetonitrile and water as mobile phase. The recoveries of pyribencarb and KIE-9749 were within 78.3~108.4% and 73.9~113.7% with RSD below 12.2% and 15.0%, respectively. The limits of quantification (LOQ) were both $0.05{\mu}g/g$. LC/ESI-MS/MS was optimized for confirmation of residue identity.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.4
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• pp.409-415
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• 1988

This study was carried out to investigate the effects of barley straw application on the eluviation of components in submerged paddy soil percolated. The chemical components of soil, percolated water and humus fraction were as follows. $NH{^+}_4$-N in percolated water and soil, $NO{^-}_3$- N in soil were not detected after prime tillering stage by absorption of rice plant. Phosphate was not affected by the application but a little amount was eluviated through a whole period. Eluviation phase of $Ca^{{+}{+}}$ was similar to $Mg^{{+}{+}}$ and the changes of $K^+$, $Na^+$ and $Cl^-$ were almost same patterns, whereas the amount of these eluviated elements in plot applied was higher than non-applied. In the plot applied, eluviation of $SO{^{-2}}_4$ was low during the tillering stage but high after heading stage, whereas the whole amount of eluviation was high during the tillering stage. Eluviation of iron in the plot applied was increased rapidly. Humus type was almost same as type B in the plot applied or not after harvest, and contents of humic acid was about 60 percent.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.4
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• pp.711-715
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• 2004

The stability of 80% ethanol-soluble pigments from Monasus purpureus CBS 281.34 was investigated according to storage temperature, pH and addition of organic acid. Also, the stability of ethanol-soluble pigment in aqueous system was examined after the addition of distilled water in the range of 0∼80% during the storage at 1$0^{\circ}C$ and 2$0^{\circ}C$ for 4 weeks with water soluble pigment. The heat stability was the highest (9.74%) when the 80% ethanol-soluble pigments were stored at 1$0^{\circ}C$ for 4 weeks. However, the 80% ethanol-soluble pigments stored at 6$0^{\circ}C$ and 8$0^{\circ}C$ for 24 h and 12 h greatly decreased by 23.06% and 30.36%, respectively. Although the 80% ethanol-soluble pigments were stable in the range of pH 4∼8, the degradation rate of pigment increased at pH 2 and PH 10.80% ethanol extract was adjusted to PH 4 by adding organic acids. The rate of pigment degradation was not different from control for 4 weeks. Red pigment was stable in the treatment of organic acids. And the stability of ethanol-soluble pigment in aqueous system was gradually decreased as the pigment content and storage time increased. Additionally, the stability of ethanol-soluble pigment was higher at 1$0^{\circ}C$ than at 2$0^{\circ}C$.

• Korean journal of applied entomology
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• v.18 no.1 s.38
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• pp.49-53
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• 1979

Paddy lands around industrial areas in Gyeonggi and Jeonbuk provinces are increasingly concerned about pollution by heavy metals. This stimulated the quantitative analysis of copper, zinc, lead and cadmium in the soil from the aress concerned. Results obtained are summarized as follows: 1. Heavy metal contents of the soil from Sue-Myun, Siheung-Gun, Gyunggi province were 20.95 ppm of Cu, 226.46 ppm of Zn, 84.17 ppm of Pb, and 2.62 ppm of Cd, respectively. Those of Anyang, Kimpo, and Jeonbuk areas were as low as the natural background levels, about 10 ppm. 2. The contentration of heavy metals of the river valley soils tended to increase from upper stream to the lower. This seemed to be caused by the fact tat disposed water from plants flows to the lower stream and metals contained in the water accummlate in the soils around the lower stream. 3. Cadmium content was exceptionally lower than 0.2 ppm in all the areas tested. The present concentartion of cadmium is not of the extent to which any injury could occur to rice plants.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.2
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• pp.116-122
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• 2006

This study was carried out to compare physical properties of the horticultural substrates measured by the European standard methods (CEN methods) and the Rural Development Administration of Korea methods (RDA methods). Sixty horticultural substrates including 40 marketed substrates and 10 organic and inorganic raw materials such as peat moss, coir dust, rice hull, perlite and zeolite were sampled. The samples were then analyzed for 6 physical properties by both CEN methods and RDA methods. The results of both methods were analyzed by linear regression. Bulk density ($R^2=0.8304$), particle density ($R^2=0.8136$) and porosity ($R^2=0.6374$) values measured by the two methods were highly significant. Whereas those for easily available water (EAW, $R^2=0.3327$), water volume ($R^2=0.2692$) and air volume ($R^2=0.0739$) were not significant. Further research is needed to facilitate the conversion between the two methods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.3
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• pp.390-396
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• 1997

Meju is a basis for manufacturing Kanjang, Meju was traditionally prepared at home by different types of process depending on the regional area. It is necessary to standardize and simplify the process of Meju-preparation for Kanjang of good quality. For these purposes, the process of Meju and Kangjang making as well as analysis of commercial Kanjang, were compared. Generally, traditional Meju was prepared by steeping and dehulling the whole soybean. After steeping for 24hr. soybean absorbed water up to 110~120% of its weight. The soaked soybeans were steamed for 2hr. and cooled to 5$0^{\circ}C$. Cooked soybeans were crushed down to the size of 10~15 mesh and molded. Molded soybeans were dried for 2 days in the air, hung up by rice straw and fermented for 20~30 days under natural environmental condition. On the other hand, commercial soybean koji was made of defatted soybean. Defatted soybeans were steeped in water and steamed for 15~30min at 0.7~1.2 kg/$\textrm{cm}^2$. Steamed and defatted soybean was cooled to 4$0^{\circ}C$. Separately, wheat power was roasted at 200~30$0^{\circ}C$ by wheat roaster. Mixture of steamed defatted soybean and roasted wheat powder (5/5 to 7/3) were inoculated with 0.1~0.2% Aspergillus sojae and incubated for 2 days at 3$0^{\circ}C$ with occasional stirring. Chemical analysis showed that traditional soy sauces contained the following composition: NaCl, 20.12~25.42%; total nitrogen, 0.64~0.91%; pure extract, 9.47~11.20%; color, 2.34~4.01; pH, 4.92~5.12. Commercial products contained: NaCl, 15.20~17.19%; total nitrogen, 1.25~1.40%; pure extract, 18.17~21.47%; color, 5.41~21.12; pH, 4.51~4.66 and ethalnol. 2.97~3.12%. Organoleptic test on taste, color and flavor of traditional and commercial soysauce indicated that most of the consumers prefer commercial products to traditional products. Preferrable formulation of Kanjang based on organoleptic test of soy sauces was assumed as containing; NaCl, 16.0%; total nitrogen, 1.40%; pure extract, 19.97%; color, 12.98; pH, 4.61 and ethanol, 2.96.

• Journal of Korea Water Resources Association
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• v.49 no.5
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• pp.373-380
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• 2016

The NRCS-CN (Natural Resources Conservation Service-Curve Number) method has been practically applied for estimating the effective precipitation. However, there are no criteria which reflect the geographic characteristics of Korea having more than 70% of mountainous and rice paddy areas, leading to significant errors in runoff calculation. Thus, it is required to estimate the runoff curve number considered Korea land use classification, however there are practical difficulties to conduct the accurate research and experimentation. In this study, after selecting target areas (urban, agriculture, forest), we performed the runoff analysis to redetermine CN values for the selected basins. To do this, curve numbers for soil type A were estimated using genetic algorithm, and then curve numbers for soil type (B, C, D) were estimated using CN aligner equation. Comparing the initial curve numbers with the estimated curve numbers, it was observed that the slightly differences at Chunwang(0), Choonyang(-1), Janggi(-3). Through the above process, this study proposed new curve numbers to reflect observed rainfall-runoff.