• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1035-1041
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• 2011

Salinity of soil under the plastic film houses in Korea is known as a significant factor to lower the crop production and to hamper the sustainable agricultural land management. In this study we propose a field monitoring technique to examine the methods applied to minimize the adverse effect of salts in soil based on the relationship between soil electrical characteristics and soil properties. Field experiments for 4 different treatments (water only, fertilizer only, DTPA only, and DTPA and fertilizer together) were conducted on soils at the plastic film house built for cultivating a cucumber plant located at Chunan-si, Chungchungnam-do in Korea. The electrical resistivity was measured by both a dipole-dipole and wenner multi-electrodes array method. After the electrical resistivity measurement we also measured the soil water content, temperature, and electrical conductivity on surface soil. The resulted image of the interpreted resistivity by the inversion technique presented a unique spatial distribution depending on the treatment, implying the effect of the different chemical components. It was also highly suspected that resistivity response changed with the nutrients level, suggesting that our proposed technique could be the effective tool for the monitoring soil water as well as nutrient during the cropping period. Especially, subsoils under DTPA treatment at 40 to 60 cm depth typically presented lower soil water accumulation comparing to subsoils under non-DTPA treatment. It is considered that DTPA resulted in increase of a root water uptake. However, our demonstrated results were mainly based on qualitative comparison. Further experiments need to be conducted to monitor temporal changes of electrical resistivity using time lapse analysis, providing that a plant root activity difference based on changes of soil water and nutrients level in time.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.1047-1050
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• 2010

This study was to investigate the effects of rice straw incorporation by cutting height on paddy soil fertility. The average residual amount of rice straw by cutting height were showed 1,420 kg $ha^{-1}$, 1,850 kg $ha^{-1}$, and 2,400 kg $ha^{-1}$ for depths of 10 cm, 15 cm, and 20 cm, respectively. For soil physical properties, soil hardness and bulk density were decreased while porosity was increased by rice straw incorporation. But soil organic matter (SOM), available silicate content, and cation exchange capacity (CEC) were significantly decreased when rice straw was removed from the field. These results indicated that the SOM as residual amount of rice straw was influenced by level of cutting height. Milled rice yield was increased by 28% and 32% for cutting heights of 15 cm and 20 cm, compared with that of control, respectively. The number of spikelets per square meter and the percentage of ripeness were increased with increasing incorporation by lower level of cutting height of rice straw. Therefore, incorporation of rice straw practices under cutting method influenced soil improvement and rice yield in paddy field.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.634-643
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• 2017

No-tillage is an effective practice to save labor input and reduce methane emission from the paddy. Effects of tillage and cultivation methods on carbon accumulation and soil properties were investigated in the treatments of tillage-transplanting (T-T), tillage-wet hill seeding (T-WS), minimum tillage-dry seeding (MT-S) and no-tillage dry seeding (NT-S) of rice. Soil carbon was higher in NT-S and MT-S, compared to T-T and T-WS. In NT-S and MT-S, soil carbon contents were the highest in the top soil (5 cm depth) and decreased with soil depth. In T-T and T-WS, however soil carbon contents showed no significant difference up to soil depth of 15 cm from the top. Carbon content was the highest in the soil particle size under $106{\mu}m$ and decreased as the soil particle size increased. Contents of water-stable aggregates in NT-S and MT-S were higher than those of T-T and T-WS. In NT-S and MT-S, contents of water-stable aggregates were the highest in the top soil and significantly decreased with soil depth while no significant difference up to the soil depth of 15 cm in T-T and T-WS. Available $SiO_2$ contents in the top soil were the highest in NT-S and MT-S while the lowest in T-T and T-WS. It is concluded that minimum or no disturbance of soil in rice cultivation can increase carbon accumulation in the soil, especially in the top layer, and subsequently contribute to the formation of the water-stable soil aggregates.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.377-382
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• 2021

Oriental melon (Cucumis melo L.) is generally cultivated on the ground by creeping culture. A farmer has a higher workload for training stems. This study was conducted to find out a new cultivation of oriental melon to reduce a workload and improve the quality of fruit. There were three treatments for training stem of oriental melon; upward stem growing, downward stem growing, control (creeping stem growing). The results of the plant growth and the net photosynthesis showed higher in upward stem growing. The root activity was higher in downward stem attract. The yield was not significant as 4,055kg/10a in upward stem attract and 3,983kg/10a in downward stem attract. According to the results of the ergonomic agricultural workload evaluation, in the case of the working posture, the working posture of creeping cultivation methods (squatting, bending) showed a higher risk level than the upward and downward cultivation methods. Therefore, it is recommended the upward stem attract of oriental melon is a new cultivation as well as an alternative method for creeping stem attract in terms of improving the plant growth and yield, and reducing the workload.

• Journal of the Korean Wood Science and Technology
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• v.47 no.4
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• pp.393-407
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• 2019

In this study, we prepared lignocellulosic artificial soil that contains Bacillus subtilis (peat moss/perlite/ steam-exploded oak wood/microbial culture = 3:1:3:3, w/w/w/w) for use in the restoration of damaged soil areas. The prepared lignocellulosic artificial soil was mixed with soil at ratios of 0%, 25%, 50%, 75%, and 100%. These mixed soils were then applied to fields, and the resultant physicochemical properties and their effects on the plant growth of Lespedeza cyrtobotrya were observed. The mixture of the prepared artificial soils (mixed at ratios of 25%-100%) with soil had a bulk densities of <$0.04g/cm^3$, porosities of >85%, pH values between 4.3 and 4.7, electrical conductivities of <0.5 dS/m, C/N ratios between 15.0 and 26.5, organic matter content between 23.6% and 43.2%, and bacterial densities between $157{\times}10^6$ and $624{\times}10^6CFU/g$. In addition, the prepared artificial soils mixed with soil at ratios of 25%-50% exhibited higher plant growth rates for L. cyrtobotrya compared with the control. Overall, we identified positive correlations between the plant growth of L. cyrtobotrya and soil bulk density, porosity, water-holding capacity, C/N ratio, organic matter, and bacterial densities.

• Journal of the Korean Applied Science and Technology
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• v.38 no.6
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• pp.1524-1532
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• 2021

In this study, Gomchwi (Ligularia fischen) derived from Taebaek-si, Gangwon-do was extracted with 70% ethanol (LFE) and antioxidant activity was measured. The following experimental techniques were used to evaluate the antioxidant efficacy of LFE. Total phenolic contents, ABTS/DPPH radical scavenging analysis, cell viability assay, NO assay, and quantitative real-time PCR technique. The content of polyphenol and flavonoid was each 113.97±0.37 mg GAE/g or 29.22±2.06 mg QE/g in LFE. DPPH radical scavenging activity was measured to be 25 ㎍/㎖ 11.26±0.95%, 50 ㎍/㎖ 17.12±0.63%, 100 ㎍/㎖ 29.54±0.36%, 250 ㎍/㎖ 68.31±0.28%, 500 ㎍/㎖ 75.12±0.05%, and 1000 ㎍/㎖ 75.75±1.57%. In addition, ABTS radical scavenging activity was identified as LFE 25 ㎍/㎖ 13.75±0.21%, 50 ㎍/㎖ 26.71±0.20%, 100 ㎍/㎖ 56.92±0.22%, 250 ㎍/㎖ 91.30±0.12%, 500 ㎍/㎖ 93.40±0.02, and 1000 ㎍/㎖ 93.19±0.04%. There was no significant cytotoxicity of LFE. NO production was significantly decreased to LFE 50 ㎍/㎖ 79.40±2.64%, 100 ㎍/㎖ 55.01±5.36%, and 200 ㎍/㎖ 30.93±3.11%. Also, the NOS2 gene expression was significantly reduced to LFE 50 ㎍/㎖ 0.94±0.11, 100 ㎍/㎖ 0.59±0.05, and 200 ㎍/㎖ 0.32±0.04. This result objectively confirmed the antioxidant effect of Gomchwi. We will continue to conduct in-depth research. Therefore, it is believed that the possibility of using Gomchwi as a cosmetic and functional food material can be established.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.880-889
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• 2021

The home meal replacement (HMR) market has attracted significant attention due to COVID-19 pandemic and products that utilize the combination of different processed ingredients are now being developed. In this study, Broughton's ribbed ark Scapharca broughtonii was soaked in seasoned soy sauce with the incorporation of mustard leaf Brassica juncea (M-BRA), which is known to have a unique texture as well as excellent functional properties such as antioxidation, to develop a regional specialty product. The optimal conditions for manufacturing M-BRA from the seasoned soy sauce (the sauce to be added [X₁] and the soaking time [X₂]), were examined using response surface methodology (RSM) to analyze the significance of the salinity (Y₁), amino-N content (Y₂), and overall acceptance (Y₃). The coefficient of determination (R²) between X₁-X₂ and Y₁-Y₃ were close to 1, thereby confirming the suitability of the RSM model. The optimal conditions were seasoned soy sauce addition of 140% and soaking time of 156 min. The M-BRA manufactured under these conditions exhibited superior overall acceptance compared to seasoned commercial soy sauce, which was used as a control. We expect that the market for M-BRA manufactured by combining marine and agricultural materials will expand owing to superior overall acceptance compared with commercial products.

• The Korea Journal of Herbology
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• v.32 no.2
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• pp.57-64
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• 2017

Objectives : Yam bean (Pachyrhizus erosus) possess various nutrients, it has been widely used as traditional cosmetic material in Indonesia. The aim of this study was to investigate the anti-oxidant activity and the anti-melanogenic effect of Yambean (Pachyrhizus erosus) extract and its fractions. Methods : The anti-oxidant activity of yam bean extract assessed based on total polyphenol, flavonoid contents, DPPH and ABTS radical scavenging assay. To evaluate anti-melanogenic effects and cytotoxicity of Yambean extract and its fractions, B16F10 melanoma cell was used. Results : In results, total polyphenol content of yam bean water extract (YW) and Yambean 70% ethanol extract (YE) were $1.18{\pm}0.03mg/g$ (mg of gallic acid/g of sample), $1.16{\pm}0.01mg/g$. Total flavonoid contents of YW, YE were $3.55{\pm}0.06mg/g$ (mg of naringin/g of sample), $1.78{\pm}0.03mg/g$. Moreover, YE scavenged DPPH and ABTS effectively in $4mg/m{\ell}$ compared to YW. Cytotoxicity of YE and its fractions in B16F10 melanoma cell was measured using MTT assays. It had no cytotoxicity up to $500{\mu}g/m{\ell}$. Melanin accumulation in B16F10 melanoma cell was induced using alpha-melanocyte stimulating hormone (${\alpha}-MSH$) and 3-isobutyl-1-methylxanthine (IBMX). B16F10 melanoma cell treated with $10-500{\mu}g/m{\ell}$ YE and hexane, ethyl acetate, butanol, $H_2O$ fractions for 24h. Non treated B16F10 melanoma cell (Control) markedly increased melanin contents. In contrast, YE ethylacetate fraction effectively suppressed melanin accumulation in a dose-dependent manner. Conclusion : In conclusion, these results suggest that Yambean extract has the potential as a cosmetic material which possess anti-oxidant and anti-melanogenic activities.

• Journal of Navigation and Port Research
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• v.46 no.4
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• pp.338-343
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• 2022

As the revitalization of the global maritime industry continues, the number of foreign ships navigating the maritime territories of maritime neighboring countries has rapidly increased. However, large-scale marine accidents have occurred, caused by the insufficient establishment of a system for management and operation relative to vessels' safety-condition. To address that, the IMO has granted the right to exercise port state control, especially for foreign vessels, to countries with jurisdiction over maritime territories with strengthening regulations and guidelines. In particular, the Republic of Korea, as a member of the TOKYO MOU, is conducting PSC, but as of 2020, the proportion of foreign ships was three times higher than that of national ships that called in domestic ports. However, the inspection rate was low at 9% which has not met the recommended level by the TOKYO MOU. Thus, this study conducted an IPA analysis as well as content analysis, by collecting the practical opinions and views of PSCO through objective questionnaires and written expert interviews, for improving the efficiency and effectiveness of domestic PSC. As a result, it was derived that the importance and performance related to human factors such as life on board, working environment, and response to safety accidents should be improved in to raise the quality of PSC inspection. Additionally, the work environment and performance of PSC in domestic ports for foreign vessels could be improved, if multifaceted support bases are established, for administrative unification of related tests for PSC, recruitment of PSCO, activation of the defection-reporting system, reorganization of the PSC execution group, etc.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.827-835
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• 2022

Commercial boiled frozen ark shell Scapharca subcrenata (BFAS) is generally used as a seasoned seafood products. One problem facing the industry is that quality decreases during thawing. This study investigated ways to improve quality and shelf-stability of BFAS for use as a non-thermally prepared seasoned seafood products. The Viable bacteria were detected in BFAS after thawing under running water, but were not detected after blanching for over 2 min at 95±5℃. Blanching and dewatering times were optimized by response surface methodology (RSM) to reduce the initial number of bacteria and improve BFAS texture. Experimental design was deemed appropriate because no significant difference (P>0.05) was observed between predicted and actual moisture content, hardness, and overall acceptance values. Optimal blanching and dewatering times were 210 s and 80 s, respectively. Optimized blanching and dewatering processes can significantly improve safety and BAFS qualities including texture. These results indicate that BFAS demand as a staple for home meal replacements can be increased by application of optimized blanching and dewatering processes, especially in Korean seafood processing companies where running water thawing is common.