• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.121-129
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• 2007

This study was conducted to evaluate the causes and effects of cyanobacterial development and succession in a shallow eutrophic reservoir from March 2003 to February 2004. Phytoplankton succession, sedimentation rate, and sediment composition were analyzed. Algal bioassay also was conducted with the consideration of light, water temperature and nutrients. Cyanobacteria dominated throughout the year, except for spring season (March${\sim}$April) in which diatoms and flagellates dominated. Total cell density increased in July and November when P loading through inflows was high. Oscillatoria spp. and Aphanizomenon sp. were dominant in May and June, respectively, but replaced with Microcystis spp. in July. Thereafter, Microcystis spp. sustained until December, and again shifted to Oscillatoria spp. and Aphanizomenon sp. The dominance of Oscillatoria spp. in May was accompanied with high TN/TP ratio and the increase of water temperature and light intensity. While the dominance of Microcystis spp. was related with relatively low TN/TP ratio, ranging from 46 to 13 (average: 27). The sedimentation rate was highest in March (0.6 m $day^{-1}$) when diatoms dominated. During the period of cyanobacterial dominance, relatively high sedimentation rate was observed in May (0.4 m $day^{-1}$) and October (0.36m $day^{-1}$). C/N ratio of the sediment ranged $6{\sim}8$. Inorganic P concentration in the pore water was low when DO concentration was < 2 mg $O_2$ $L^{-1}$ in the hypolimnion, reflecting the P release from the sediment. Cyanobacterial growth rate depended on phosphorus concentration and water temperature, and high P concentration compensated for the low temperature in the growth rate. Our results suggest that the potential of cyanobacterial development and substantiality in eutrophic reservoirs be high throughout the year, as being supplied with enough P, and emphasize the consideration of sediment man. agement for the water quality improvement and algal bloom control.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.6
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• pp.708-722
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• 2016

Land-Ocean Interactions in the Coastal Zone (LOICZ) models for nutrient budgets were used to estimate the seasonal capacity of the Youngsan Estuary and Youngam-Geumho Estuary to sink and/or supply nutrients such as dissolved inorganic phosphorus (DIP) and nitrogen (DIN) to provide an understanding of the behavior of the coupled biogeochemical cycles of phosphorus and nitrogen in the estuaries (Youngsan Estuary, Youngam-Geumho Estuary) near Mokpo Harbor. During non-stratified periods (May, September, and November, 2008), simple three-box models were applied in each sub-region of the system, while a two-layer box model was applied during on-site observation of stratification development (July, 2008). The resulting mass-balance calculation indicated that even after large discharges from artificial lakes (in May and July), DIP influxes due to a mixing exchange ($V_{X-3}$, or $V_{deep}$) were more than terrigenous loads, indicating the backward transportation of nutrients from a marine source. The model results also indicated that for nutrient loads (DIP and DIN fluxes) in September, an extreme congestion of nutrients occurred around the mouths (sub-region III of the model) of the estuaries, possibly due to an imbalance in physical circulations between the estuaries and offshore locations. In November, the Youngam-Geumho Estuary, into which freshwater was discharged from artificial lakes (Youngam and Geumho Lake), showed nutrient enrichment in the water column, but the Youngsan Estuary showed nutrient depletion. In conclusion, to efficiently control water quality in the estuaries near Mokpo Harbor, integrated environmental management programs should be implemented. I.e., the reduction of nutrient loads from land basins as well as the deposit of nutrient loads into adjacent coastal lines.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.400-409
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• 2015

This study examined the plant growth and development characteristics of leafy vegetables on the hydroponic substrates of waste wood chips, radiate pine chips, and mat type of waste wood chips. The bulk density of waste wood chips and radiata pine chips were $0.2g/cm^3$ and $0.16g/cm^3$, respectively. The moisture retention properties of both the radiata pine chips and waste wood chips were found to be similar but not better than those of the control rock wool and coco peat hydroponic substrates. The moisture retention property of the mat type was found to be the lowest. The chemical analysis of waste wood hydroponic substrates (w/v) was as follows.; The pH was 6.59, electric conductivity was 6.76 dS/m, total nitrogen content was 0.5%, C/N ratio was 113%, phosphorus was 10.1 ppm, potassium was 77 ppm, calcium was 531 ppm, magnesium was 49 ppm, and sodium was 96 ppm. The results from the radiata pine chemical analysis showed that it had a pH of 5.29, electric conductivity of 4.49 dS/m, total nitrogen content of 0.32%, C/N ratio of 180%, phosphorus of 6.4 ppm, potassium of 83 ppm, calcium of 97 ppm, magnesium of 29 ppm, and sodium of 59 ppm. Except for the plants grown in mat type, the developmental characteristics of the plants grown in rock wool and coco peat hydroponic substrates were similar. Based on the results of the experiment, waste wood resources may possibly be used as an organic solid medium in place of the existing rock wool and coco peat medium.

• Journal of Aquaculture
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• v.17 no.2
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• pp.144-150
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• 2004

This experiment was conducted to evaluate the parameters such as nutrient requirements, POY, AnV, Totox, VBN, total plate count, dietary fatty acids and amino acids composition, that are not included in the registered standard composition items required by the Ministry of Agriculture and Forestry, of a moist pellet (MP), three domestic extruded pellets (DEP-1, DEP-2, DEP-3), and two foreign extruded pellets (FEP-1, FEP-2) that are utilized by domestic flounder farms at present. The crude protein was added in excess of the dietary protein requirement in 6 kinds of feeds. When considering the proper PH ratio, it is obvious that protein was added in excess, especially in MP and FEP-2. Crude fat was also added in excess, especially in FEP-1. MP contained a higher dietary phosphorus content than formulated feeds, surpassing the dietary phosphorus requirement and greatly increasing the possibility for causing water pollution. The oxidation of fatty acid and decomposition of protein in MP were higher than in formulated feeds, and may also cause problems on fish farms. Also, it is difficult to store and manage MP, Among the fatty acids, EPA and DHA contents in MP were higher than those in formulated feeds. It is necessary to conduct further studies of EPA and DHA contents in formulated feeds. Lysine content in MP and FEP-2 could meet the dietary lysine requirement of flounder, however, the possibility of insufficient lysine content in the other formulated feeds was high and we considered that extra supplementation was necessary. Therefore, it is necessary to set up quality control standards according to fish species and sizes while considering the specific character of aquatic formulated feeds to restore the confidence of feed companies and aquaculturists to these feeds. This may be an opportunity to make an earlier change from MP to formulated feeds.

• Journal of Korean Society of Forest Science
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• v.105 no.2
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• pp.177-185
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• 2016

Fertilization is required to keep the balance of tissue nutrients and to produce high quality seedlings at the permanent nursery. This study was conducted to verify the optimum fertilization method for Fraxinus rhynchophylla, F. mandshurica, Pinus koraiensis, and Abies holophylla seedlings with vector diagnosis method. Seven treatments include nitrogen (N, $13.8g{\cdot}m^{-2}$), phosphorus (P, $6.1g{\cdot}m^{-2}$), potassium ($7.5g{\cdot}m^{-2}$) fertilization and 1x (N $6.9g{\cdot}m^{-2}$, P $3.05g{\cdot}m^{-2}$, K $3.65g{\cdot}m^{-2}$), 2x (twice of 1x), 4x (four times of 1x) fertilization and no fertilization. Soil pH decreased as fertilization increased. Nitrogen and NPK fertilization decreased exchangeable $Ca^{2+}$ and $Mg^{2+}$ concentrations. Height and root collar diameter of F. rhynchophylla and F. mandshurica significantly increased with N and NPK fertilization, but those of P. koraiensis and A. holophylla did not. The biomass of F. rhynchophylla and F. mandshurica was about twice higher at NPK fertilization compared to the control. The responses of vector diagnosis were different by tree species and fertilization treatment: F. rhynchophylla was in the status of N "dilution", which means the N concentration decreases with N content. Phosphorus and K were "sufficiency" state with 4x fertilization. F. mandshurica showed "retranslocation" as N content decreased without change of dry weight at N, P, K fertilization, but "dilution" state at NPK fertilization. This result suggested that optimal fertilization was required for F. rhynchophylla and F. mandshurica in seedling production stage, but was not essential for P. koraiensis and A. holophylla.

• Applied Biological Chemistry
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• v.15 no.1
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• pp.77-84
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• 1972

A field experiment was conducted to determine the factors responsible in limiting nutrient up take and root activity in low productive paddy fold. Radiosotope of phosphorus-32 was used as a tracer. Results of the study were as follows: 1. On yield components responsible for increase yield indicated that number of ears per panicle and ripening ratio were closely related to increase yield. 2. Root volume or root feeding area has significant influence in increasing rice yield. 3. Root volume indicative of root activity and nutrient uptake can be effected by reasonable water control. 4. The combined application of calcium, silica, and magnesium(as a fused magnesium phosphate. the Kyun-gi Chemical Co. products.) with water control, although under conditions of large amount application of nitrogen, was found to be increased the maturing rate. 5. In the plots of water control, the number of roots per one volume were less than that of the continuous flooding plots, but the weight per root was heavier than the flooding plot ones. 6. Improvement of the present native culture method could effectively increase paddy rice yield.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.8
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• pp.1050-1061
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• 2009

The present study was performed to evaluate energy and nutrients intakes of stroke patients in Daegu Gyeongbuk region, and to analyze the relative risk of stroke related to the intake levels of energy and nutrients. The case subjects (n=100) were selected from newly diagnosed stroke patients at Kyungpook National University Hospital. The control subjects (n=150) were selected from community residents who did not have stroke history and were sex and age-matched with the case subjects. The survey was conducted by individual interviews by trained dietitians using semiquantitative food frequency questionnaires. The odds ratios were calculated by using unconditional logistic regression. In male subjects, patient group had significantly higher consumption than the control group in mean daily intakes of energy, all energy yielding nutrients, vitamin $B_1$, $B_6$, niacin, folic acid, vitamin E, phosphorus, potassium, zinc and dietary fiber, and also in the ratio of energy intake from protein and fat. In women subjects, the patient group consumed significantly lower intakes than the control group in fat, vitamin C, folic acid, vitamin E, iron, but vice versa in carbohydrate energy ratio. As for men, the increased intakes of energy, protein, carbohydrate vitamin $B_1$, E and niacin, zinc, total fatty acids, monoand poly-unsaturated, n-6 fatty acids significantly raised the relative risk of stroke. As for women, the increased intakes of fat, vitamin A, $B_2$, $B_6$, niacin, vitamin C and E, iron, sodium, potassium, selenium, mono-, poly-unsaturated, n-6 fatty acids, cholesterol, taurine and dietary fiber significantly lowered the relative risk of stroke. The results of the study demonstrated that the effect of several nutrient intake levels, such as niacin, vitamin E and fatty acids, on the relative risk of stroke was inconsistent between sex. The reason for this sex difference needs to be elucidated in a larger scale study.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.4
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• pp.72-86
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• 2014

This study was conducted to investigate the effects of mulching of easily-decomposable organic materials including rice powder and corn starch on rice paddy fields. The treatments were including seven mulching materials each consisted of rice powder [Rice], starch with black color [Starch-B] and transparent [Starch-T] and stone powder [Stone], and conventional vinyl [Conventional], no-mulching without herbicide [Control-O] and no-mulching with herbicide [Control-C]. Rice growth and yield were different among the treatments; the highest yields were observed for [Rice] ($6.51ton\;ha^{-1}$) and [Conventional] ($6.47ton\;ha^{-1}$) followed by [Starch-T] ($6.25ton\;ha^{-1}$) and [Stone] ($6.20ton\;ha^{-1}$) which is comparable to the [Control-C] ($6.15ton\;ha^{-1}$). However, [Starch-B] showed lower rice yield ($4.93ton\;ha^{-1}$) than the [Conventional] or [Control-C]. Mean soil temperature ranged form 23.6 to $24.1^{\circ}C$ with the highest temperature for [Rice] treatment, and cumulative soil temperature was also significantly higher in the [Rice] treatment. Among the soil parameters, electrical conductivity, organic matter content, and phosphorus concentration were also different among the treatments. The amount of earthworm casting was higher for [Rice] treatment ($17.7kg\;m^{-2}$) compared to the others ($5.5{\sim}9.8kg\;m^{-2}$). It was suggested that mulching of rice fields with organic materials containing rice powder is better than others in respected to rice yield and earthworm activity.

• 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 Forest Science
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• v.83 no.4
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• pp.486-497
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• 1994

The objective of this study was to examine the effects of air pollution on Pinus thunbergii forests surrounding Sasang industrial complex in Korea. The injury index, contents of chlorophyll and mineral elements, and concentrations of water soluble sulfur in needles were investigated at sample plots surrounding industrial complex and compared with those of control far from industrial complex. The results obtained are as follows ; 1. Discoloration of Pinus thunbergii needles was severe in the vicinity of industrial complex, and the older needle age classes was the more severe its injury appeared. Injury index was increased in the vicinity of industrial complex. 2. Water-soluble sulfur concentration was high in the vicinity of industrial complex at all of needle age classes, and those of all plots were higher than that of control. 3. Chlorophyll a contents were lower at surrounding industrial complex than that at control. It was supposed that chlorophyll a was destroyed by air pollutants. Total chlorophyll contents and content ratio of chlorophyll a to b were influenced by decrease of chlorophyll a contents. 4. Phosphorus contents in needles were decreased even in remoted regions with the increase of needle age classes. Colcium contents in needles were decreased near industrial complex at all needle ages classes. 5. There were negative correlation, between injury index and chlorophyll contents, injury index and calcium contents, and there were positive correlation between injury index and calcium contents. 6. Cluster analysis was carried out to divide the injured regions on sample plots. As a result of the analysis, there were devided 3 regions, severe regions(1-8 plots), medium regions(9, 10, 11, 12, 15, 17 plot), slight(13, 14, 16, 18, 19 plot and control). 7. The cross section of visible injured needle showed the destruction of mesophyll cell, sclerenchyma cell in the outside of resin duct and endodermis, partially.