• Journal of Korean Society of Environmental Engineers
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• v.35 no.8
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• pp.554-563
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• 2013

The purpose of this study is to evaluate the possibility of nutrient release at up and downstream of Kangchun weir, upstream of Yuju and Ipo weir in Namhan River. For this survey, we measured basic characteristics of the sediments (water content, ignition loss, TOC, TP, SRP, TN, phosphorus fractionation) and conducted nutrients release experiments under both aerobic and anaerobic condition. The overlying water from the sediment-water column was analyzed for nutrients (i.e. TP, $PO_4$-P, TN, $NO_3$-N, $NH_3$-N) everyday for 18days. Result of soil texture experiment showed that sediments are Sand. SRP concentration before the release experiment was different with the value after the release experiment. According to this result, we can find that there were more activated release processes in anaerobic condition. $PO_4$-P increased from 1 to 8 days and remained at the maximum value (7~8 days) afterward. The rapidly increase of $PO_4$-P was observed from 1 to 2~3 days whereas the TP continuously increase from 1 to 18 days. The $PO_4$-P release rate calculated by up to 7~8 days data highly correlated with initial SRP concentration with $R^2$=0.8502. $NO_3$-N release rate appears constantly decreasing trend as -5.7~-3.08 $mg/m^2{\cdot}day$, otherwise the $NH_3$-N release rate, by-product of a organic matter decomposition using nitrate as electron acceptor, was 0.57~2.41 $mg/m^2{\cdot}day$. Substantial portion in TN can be induced by organic nitrogen which originated from the tributary passing through non-point pollutant source. Compared with other similar researches, phosphorus and nitrogen release rates obtained in this study can be considered as relatively low values. Since this study targeted the sediments accumulated by one time of flooding season, there are limitation to generalize theses results. Therefore, it is necessary to consistently monitor and investigate the accumulation of nutrients in the sediment for understanding the effect of weir construction on the overlying water quality.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.1
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• pp.8-14
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• 2006

High phosphate accumulations in greenhouse soils have been considered as a new agricultural problem in Korea. The effects of silicate on changes in phosphate fractions and on the yield of Chinese cabbage without P fertilization were investigated by pot experiment. For this experiment, P-accumulated soil was selected (Total-P; $2140mg\;kg^{-1}$). Three levels of silicate (0, 2, and $4Mg\;ha^{-1}$) without P fertilization and P fertilizer without silicate application (Si0+NPK) were applied in 1/2000a pots. The same amount of nitrogen and potassium fertilizers were applied to the all pots. The application of $4Mg\;ha^{-1}$ of silicate greatly increased the yield of Chinese cabbage by 25% compared to Si0+NPK treatment. Although there is no significant difference in plant P absorption among all the treatments, the uptake of P in the $4Mg\;ha^{-1}$ silicate application was significantly higher than Si0+NPK treatment due to increase in yield. The content of available $SiO_2$ in soil increased with increasing silicate application rates. The Si concentration of plant showed a positive correlation with available $SiO_2$ contents in soil and the yield of Chinese cabbage. Total P greatly decreased with increasing rates of silicate application, yet the change in available P content was not significant. The Si0+NPK treatment increased the content of Ca-P by 11%, however, which was decreased by 27% in the $4Mg\;ha^{-1}$ silicate application. Therefore, the effect of silicate on reducing total-P was mainly attributed to the change in concentration of Ca-P. Our results suggest that the application of silicate in P-accumulated soils not only increase the crops yield but also reduces phosphate accumulation.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.203-210
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• 2001

In order to environmentally use wood chips manufactured from low valued forest resources by forest tendering, wood chips were used for the evaluation on chips characteristics, decomposition capability of organic wastes, and field experiment and determination of conditions for decomposer. Bioclusters manufactured by Cryptomeria japonica, commercially available wood chips in Japan, showed higher pore ratio, water reservation and water resistance, and higher cellulose content with lower hot water solubles than domestic wood chips. The useful size of wood chips for swine manure decomposition was 10 (length) ${\times}$ 5 (width) ${\times}$ 2 (thickness) mm, and cellulose contents and alkali solubles of Pinus densiflora and Populus tomentiglandulosa were similar to those of bioclusters. According to the decomposition ratio depending on wood species, it was ordered as Pinus densiflora > Pinus koraiensis > Cryptomeria japonica. The swine manure decomposition ratio depending on treatment hours by Pinus koraiensis was constant with the ratio of 15 to 16 g per hour by 1 kg of chip, indicating of daily swine decomposition amount of 390 kg by 1 ton of chips which was equal to the amount of daily swine manure production by 70 swines. Analyzing by long term used wood chips during 40 days treatment, the treated wood chips characteristically showed stable total nitrogen content, suitable pH, high accumulation of inorganic contents such as calcium, phosphorus, potassium and sodium, and no odor. During winter, the inner temperature of decomposer was kept at $43^{\circ}C$, but air bubble was occurred due to high pH and viscosity of swine manure. The most appropriate mixing ratio between wood chips and swine manure was 1 versus 2 or 3, and at more than ratio 1 versus 3, ammonia gas was caused because of anaerobic fermentation status by high moisture content of wood chips. The mixing interval of decomposer was 3 mins. per hour for the best swine decomposition.

• Applied Biological Chemistry
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• v.21 no.1
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• pp.40-50
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• 1978

Effects of Zn, P and Fe on Cd uptake and accumulations by tomato (Lycopersicum esculentum Mill) and also their interactions on the uptake of Zn, Fe, Mn, P and Cd were investigated using batch type solution culture technique. Experiment 1 was a factorial scheme with 3 levels of Zn (0, 0.5, 2.5 ppm) and 3 levels of Cd (0, 0.2, 1.0 ppm). At 1.0 ppm Cd, significant yield reduction of dry matter and visual toxicity symptoms (yellowing and necrosis) of Cd was observed for all zinc levels. At this Cd level, increasing Zn treatment from 0 to 2.5 ppm increased Cd concentration from 199 to 235 ppm in leaves and from 124 to 145 ppm in stems. Similarly, Cd treatment did not suppress Zn uptake in leaves, and rather significantly increased in stems. Fe concentrations in leaves and stems were significantly reduced due to Cd treatment while Mn were increased by both Zn and Cd treatment. The results of experiment 2 with 3 levels of P (0.5, 2.0, 4.0m Mol) and 3 levels of Cd (0, 1.0, 2.0 ppm) in a factorial scheme also showed a growth reduction and visual toxic symptons from 1.0 ppm Cd level. Increasing P treatment tend to increase Cd concentrations in leaves and stems although it was not statistically significant. Increasing P concentration due to Cd treatment could be the 'concentration' effect as a result of reduced growth, while there was significant decrease in Fe concentration due to Cd treatment in spite of possible 'concentration' effect. Mn concentration was increased at 1.0 ppm Cd level and then dropped at 2.0 ppm Cd level. Zu concentration in leaves and stems showed significant increase as Cd treatment increased as observed in experiment 1. Experiment 3 had 3 levels of Fe (0.5, 1.0, 2.0 ppm) and 3 levels of Cd (0, 0.8, 1.6 ppm) treatments in a factorial design. Significant growth reduction and visual toxic symptoms as observed in experiment 1 and 2 were also observed from 0.8 ppm Cd level. Increasing Fe treatment obviously alleviated toxic symptoms, improved growth and significantly increased dry matter yield. At 0.8 ppm Cd treatment level, increasing Fe treatment from 0.5 to 2.0 ppm significantly decreased Cd concentration from 141 to 92 ppm in leaves and from 101 to 46 ppm in stems. At 1.6 ppm Cd treatment level the decrease was from 224 to 167 ppm in leaves and from 124 to 109 ppm in stems. As in the case of experiment 1 and 2, Fe concentration in leaves and stems were reduced as Cd treatment increased to 1.6 ppm at 0.5 and 1. 0 Fe treatment levels, whereas at 2.0 ppm Fe level, Cd treatment increased Fe concentration in leaves and stems showing significant interactions of Fe and Cd on Fe uptake. Cd effect on Zn and Mn showed similar results to experiment 1 and 2 and Fe treatments reduced Zn and Mn concentrations in plant tissue. The results of 3 experiments show that P and Zn did not manifest suppressive effect on Cd uptake, Fe significantly demonstrated it. Fe also alleviated Cd toxicity symptoms significantly in terms of visual symptoms and dry matter yield. Visual toxicity symptoms were definitely related to Fe status in plant tissue as well as possible physiological effect of Cd itself, and the results suggest that Fe requirement for normal growth increase as Cd element is present in plant tissue. Zn accumulated more in stems than in leaves whereas Cd, Fe and Mn showed the opposite trend in all experiments.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.343-350
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• 2016

The aim of this study was to evaluate effects of immature compost on the amount of nutrient content, heavy metal concentration, and application rate that were used for lettuce cultivation. The characteristics of the two composts (Compost A (CA) was immature compost and Compost B (CB) was mature compost) were evaluated upon mixing with commercial soil at 0%, 25%, 50%, and 75% (w/w). The poor chemical characteristics were appeared by use of immature compost as soil amendment; the 50% and 75% rates were weakly acidic at pH 5.39 and 5.50, respectively. The total carbon content at using of 75% of the immature compost and mature compost increased the most to 14.5 and 6.5% and it significantly increased concentrations of the total nitrogen and phosphorus compared to control. As for 75% mature compost rate increased significantly the concentrations of Cu ($128mg\;kg^{-1}$), Zn ($260mg\;kg^{-1}$), Pb ($0.32mg\;kg^{-1}$) and, Cd ($0.48mg\;kg^{-1}$) compared to control, and the highest As concentration increased significantly at 75% and 50% (6.69 and $6.28mg\;kg^{-1}$) including in 25% immature compost as $6.48mg\;kg^{-1}$. However, all of the high compost rates significantly decreased the shoot biomass of lettuce. The immature compost was potentially amended at an application rate of 25% due to a slight salinity and low risk to heavy metal uptake on lettuce growth. This use may be available if the rate is lower than that used in this trial.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.4
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• pp.425-437
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• 2007

Flow distribution of water and sedimentation rate were investigated to understand the hydrodynamics and settling characteristics of particulate materials in a constructed wetland for treatment of non-point sources pollutants, the Sihwa constructed wetland, Korea. The Sihwa constructed wetland is divided into three sub-wetlands(the Banwol, the Donghwa and the Samhwa wetlands) to treat the polluted water from three streams, the Banwol stream, the Donghwa stream and the Samhwa stream. From the results of water flow experiment using dye(Rhodamine 50WT Red), it was found that the water flow in the wetland was prevailing at the waterway and open water. Dye was spread slowly in the closed water area planted by plants. The mean hydraulic retention time(HRT) at the upper area of high wetland and lower wetland of Banwol, was found to be 34.1 hr at the upper area and 74.6 hr at the lower area respectively, totaling approximately 108.7 hr(4.5 days). The sedimentation rate was higher at lower area(sites of B, C and D) of the wetland than upper area(site of A which is settling zone). Based on the forecast for 20 years as to the amount of sediment that can be deposited in the open water in the future, the sediment depth of each area would be like this: A: 6.3 cm, B: 8.3 cm, C: 7.0 cm, D: 9.5 cm. The contents of organic materials in the sediment deposited within the sediment trap were found to be higher overly in the first investigation period which had much rainfall, and B, C and D areas were found to have an increased COD accumulation than A area. Also, nitrogen and phosphorus were found to increase in the down-stream of the wetland. The results of this study suggest that a sustainable research and management for the characteristics of water flow pattern and sedimentation changeable as time passes is needs to maintain or improve the efficiency of water treatment in the constructed wetland.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.225-237
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• 2018

This study was conducted to compare nutritional analysis and neuroprotective effect of 5 cultivars of Diospyros kaki (Dungsi, Godongsi, Gojongsi, Gabjubaekmok, and Bansi). In nutritional analysis, three free sugars: sucrose, glucose, and fructose, and six fatty acids: tartaric acid, hexadecanoic acid, palmitic acid, oleic acid, octadecenamide, and octadecane, were detected. Potassium and phosphorus levels were the highest in inorganic component analysis, and glutamic acid and aspartic acid were the highest contents in amino acid analysis. Vitamin C was detected in all cultivars. Total phenolic content was the highest in Dungsi. Antioxidant activities such as ABTS (3-ethylbenzothiazoline-6-sulfonic acid), DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activities, FRAP (ferric reducing/antioxidant power), and MDA (malondialdehyde) inhibitory effect were the highest in Gabjubaekmok. Acetylcholinesterase inhibitory activity, cell viability, intracellular reactive oxygen species (ROS) accumulation, and lactate dehydrogenase (LDH) release were measured to confirm the neuroprotective effect in MC-IXC cells. Gabjubaekmok showed significant acetylcholinesterase (AChE) inhibition and neuroprotection.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.75-82
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• 2010

Indoor cultivation plots for watermelon plant mostly have salt-accumulation problem because of continuous cropping especially with the heavy applications of chemical fertilizers. Thus, this study was conducted to investigate selected soil properties and watermelon growth condition as affected by the application of different farming practices in the salt-affected soils of greenhouse plots used for continuous watermelon production. Five different practice conditions in the experimental plots were applied, 1) a conventional farming practice (CFP), 2) a nitrogen-phosphorus-potassium (NPK) fertilizer management practice (FMP), and 3) the FMP with different amounts (5, 10, and 15 ton $ha^{-1}$)of fresh rice straw treatments (FMP-RS), for three years of study. As comparing with CFP plots, soil organic matter content gradually increased during the experimental years, whereas it decreased in the FMP only plot. Soil pH was not changed in the CFP and FMP plot, but it declined in the FMP-RS plots; however, it increased again from the third year in the FMP-RS plots with applying 10 and 15 ton $ha^{-1}$ of RS treatments. The concentrations of exchangeable cations, $Ca^{2+}$ and $Mg^{2+}$, except $K^+$, and water-soluble anions, ${NO_3}^-$, $Cl^-$, ${SO_4}^{2-}$ and ${PO_4}^{3-}$, markedly decreased in FMP and FMP-RS plots. In particular, the application of rice straw tended to significantly decrease the ion concentrations, especially most anions, in the first year, but there was no more decrease in the second and third study years. With relation to the ion concentrations, the changes of electrical conductivity (EC) after applying the management practices showed very similar to those of the ion concentrations. In addition, incidence of withered watermelon plant after applying the management practices dramatically declined from approximately 20% in the CFP plot to 3.5% in the FMP-RS plots. Water melon fruit weight was also improved by the management practices, especially FMP-RS. Therefore, the fertilizer and/or fresh rice straw application management practices are beneficial to improve salt-affected soils and watermelon plant growth condition.

• Journal of Wetlands Research
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• v.12 no.1
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• pp.1-14
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• 2010

Changes in wetland soil properties of two constructed wetlands after their constructions were compared to those of a natural wetland to determine if they could be used for the evaluation of the success of constructed wetlands and the assessment of their functions. One natural wetland as a reference wetland and two constructed wetlands(treatment wetland and experimental wetland) with different contaminant inflow characteristics were selected for this study. Major physicochemical properties of wetland soil such as soil texture, water content, pH, CEC(cation exchange capacity), organic matter content, total nitrogen, and available phosphorus were monitored to investigate the effects of inundation and accumulation of organic matters and nutrients on the wetland soil development. There was a clear difference in soil texture between the natural wetland and the constructed ones, with the high sand content in the constructed wetlands as compared to the high clay content in the natural one. Gradual increases of silt and clay contents over time were observed in the constructed wetlands. The soil of the natural wetland was higher in water content and organic matter but lower in pH than those of the constructed wetlands. The pH of the constructed wetlands reached near neutral ranges after initial increase. CEC and nutrient concentrations of the constructed wetlands seemed to be affected mainly by outside inflows of organic matter and contaminants. Concentrations of organic matter and nutrients decreased over time in the experimental wetland where surface and deep soils with different characteristics were mixed during its construction, suggesting that changes in soil properties during wetland constructions may affect the development of wetland soils or wetland biogeochemistry. This study showed that changes in physicochemical properties of soils in constructed wetlands could be used to assess the success of constructed wetlands and their functions, and also the importance of reference wetlands for the appropriate assessment.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.2
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• pp.115-123
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• 2016

In this study, the effect of energy and protein ratio on the nutrient availability and body weight gain was determined to find the proper nutrient level for the stage of replacement dairy heifers before fertilization at approximately 12~24 months old after birth. Dry matter intake showed that the TDN/CP rate of T1 (5.0:1), T2 (4.5:1) and T3 (4.0:1) resulted in similar values. Among feces, the ash content of T1 was 11.07%, which was significantly (p < 0.05) higher than that of T3 (9.69%). It was also significantly (p < 0.05) higher than that of T2 (10.32%). When the TDN/CP rate was increased, the ash content in the feces was also increased. Regardless of the initial weight, weight gain was increased significantly as the CP rate in the feed was increased on the $30^{th}$ day. On the $60^{th}$ day, T2 showed the highest rate of gain (p < 0.05). As the TDN rate was decreased or the protein rate was increased, weight gain was significantly (p < 0.05) increased. Regarding GPT level in the blood after finishing the test, T1 and T3 (112.6, 88.3 u/l) showed significantly (p < 0.05) higher value than T2 (50.9 u/l). For phosphorus level, T1 (46.3 mg/dl) showed significantly (p < 0.05) higher value than other treatments. For HDL cholesterol level, T2 (145.2 mg/dl) had significantly (p < 0.05) higher level than T1 (121.0 mg/dl) or T3 (132.3 mg/dl). For triglyceride levels, T3 (40.6 mg/dl) had significantly (p < 0.05) higher value than T1 (20.7 mg/dl) and T2 (29.0 mg/dl). For other blood parameters including BUN concentration, there were no significant (p > 0.05) difference among treatments. As a result, although feed intake and weight gain with TDN/CP rate of 4:1 showed best results, considering the excess body fat accumulation possibilities or blood metabolism, it seems 4.5:1 ratio is most appropriate.