• 한국환경과학회지
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• 제22권12호
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• pp.1683-1690
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• 2013

We investigated the spatial and temporal variations of phytoplankton in Youngil Bay as well as the effect of water physico-chemical parameters. Water samples at three stations were collected and measured monthly from May to November in 2010. The taxa of phytoplankton observed in this study were classified as 33 Bacillariophyceae, 23 Dinophyceae, 1 Euglenophyceae, 2 Crysophyceae and 1 Cryptophyceae. The highest biomass of phytoplankton was observed at inner station in September, which was characterized high concentration of dissolved inorganic phosphate(DIP) in surface water after rainfall. Nutrient concentrations, chlorophyll-a and phytoplankton biomass values showed the marked trend to decrease from the inner bay to the outer bay. Pearson's correlation co-efficient between salinity and other water parameters including chlorophyll-a, pH and DIP showed the strong negative relationship r=-0.82, r=-0.78 and r=-0.75 (p<0.01), respectively. These results indicate that the water quality of Youngil Bay could be stimulated by nutrient enriched input from Hyeogsan River discharge, and the spatial and temporal distribution of phytoplankton biomass principally limited to DIP concentration from Hyeogsan river.

• 한국해양환경ㆍ에너지학회지
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• 제1권2호
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• pp.60-70
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• 1998

국내에서 가장 전형적인 폐쇄성 해역인 마산만은 연안도시인 마산시와 창원시의 배수지역이다. 유역인구가 약 100만명으로 증가된 시점인 1993년 11월에 마산시 덕동하폐수종말처리장이 가동되기 시작하였으며, 그 유출수는 마산내만에서 약 15km 떨어진 옥계해역에 방류되기 시작하였다. 본 연구에서는 마산만 유입부하의 분포가 어떻게 변화하였으며, 유입부하량과 유입오염물질의 성상은 어떠한 가를 규명하였다. 또한 마산만 유입부하 특성의 변화가 폐쇄성 연안 수질에 어떠한 영향을 주고 있는가를 연구하였다.

• 한국물환경학회지
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• 제23권5호
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• pp.689-696
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• 2007

Kinetic analysis was important to develope the biological nutrient removal process effectively. In this research, anoxic-anaerobic-aerobic system was operated to investigate kinetic behavior on the nutrient removal reaction. Nitrification and denitrification were important microbiological reactions of nitrogen. The kinetics of organic removal and nitrification reaction have been investigated based on a Monod-type expression involving two growth limiting substrates : TKN for nitrification and COD for organic removal reaction. The kinetic constans and yield coefficients were evaluated for both these reactions. Experiments were conducted to determine the biological kinetic coefficients and the removal efficiencies of COD and TKN at five different MLSS concentrations of 5000, 4200, 3300, 2600, and 1900 mg/L for synthetic wastewater. Mathematical equations were presented to permit complete evaluation of the this system. Kinetic behaviors for the organic removal and nitrification reaction were examined by the determined kinetic coefficient and the assumed operation condition and the predicted model formulae using kinetic approach. The conclusions derived from this experimental research were as follows : 1. Biological kinetic coefficients were Y=0.563, $k_d=0.054(day^{-1})$, $K_S=49.16(mg/L)$, $k=2.045(day^{-1})$ for the removal of COD and $Y_N=0.024$, $k_{dN}=0.0063(day^{-1})$, $K_{SN}=3.21(mg/L)$, $k_N=31.4(day^{-1})$ for the removal of TKN respectively. 2. The predicted kinetic model formulae could determine the predicted concentration of the activated sludge and nitrifier, investigate the distribution rate of input carbon and nitrogen in relation to the solid retention time (SRT).

• 한국토양비료학회지
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• 제49권6호
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• pp.819-825
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• 2016

Monitoring of soil fertility and crop productivity in long-term application of silicate fertilizers is necessary to use fertilizers efficiently. This study was conducted to investigate effects of continuous application of silicate fertilizer for rice cultivation from 1969 to 2014. The treatments were no silicate fertilizer treatments (N, NC, NPK, and NPKC) and silicate fertilizer treatments (N+S, NC+S, NPK+S, and NPKC+S). The 46-yr input of $2\;ton\;ha^{-1}yr^{-1}$ of silicate fertilizer increased pH 0.6 ~ 1.1 and exchangeable Ca $2.0{\sim}2.4cmol_c\;kg^{-1}$ in silicate fertilizer treatments (N+S, NC+S, NPK+S, and NPKC+S) compared with no silicate fertilizer treatments (N, NC, NPK, and NPKC) because silicate fertilizer included Ca component. Also, available silicate concentrations of silicate fertilizer treatments (N+S, NC+S, NPK+S, and NPKC+S) increased $169mg\;kg^{-1}$ compared to no silicate fertilizer treatments. In Period II ('90~'14), the mean annual Si field balance varied from 62 to $175kg\;ha^{-1}yr^{-1}$ in silicate fertilizer treatments, indicating continuous accumulation of soil Si. Silicon uptake and grain yield of rice had greater differences between N treatment and N+S treatment than other treatments. This showed that the application of silicate fertilizer had greater effect in nutrient-poor soils than in proper nutrient soils. Thus the application of silicate fertilizer led to improvement the fertility of soil and increasement of rice production for the lack of soil nutrients.

• Asian-Australasian Journal of Animal Sciences
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• 제33권12호
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• pp.2039-2049
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• 2020

Objective: This study was conducted to provide models to accurately predict nitrogen (N) and phosphorus (P) excretion of dairy cows on smallholder farms in Indonesia based on readily available farm data. Methods: The generic model in this study is based on the principles of the Lucas equation, describing the relation between dry matter intake (DMI) and faecal N excretion to predict the quantity of faecal N (Q_FN). Excretion of urinary N and faecal P were calculated based on National Research Council recommendations for dairy cows. A farm survey was conducted to collect input parameters for the models. The data set was used to calibrate the model to predict Q_FN for the specific case. The model was validated by comparing the predicted quantity of faecal N with the actual quantity of faecal N (Q_FNACT) based on measurements, and the calibrated model was compared to the Lucas equation. The models were used to predict N and P excretion of all 144 dairy cows in the data set. Results: Our estimate of true N digestibility equalled the standard value of 92% in the original Lucas equation, whereas our estimate of metabolic faecal N was -0.60 g/100 g DMI, with the standard value being -0.61 g/100 g DMI. Results of the model validation showed that the R² was 0.63, the MAE was 15 g/animal/d (17% from Q_FNACT), and the RMSE was 20 g/animal/d (22% from Q_FNACT). We predicted that the total N excretion of dairy cows in Indonesia was on average 197 g/animal/d, whereas P excretion was on average 56 g/animal/d. Conclusion: The proposed models can be used with reasonable accuracy to predict N and P excretion of dairy cattle on smallholder farms in Indonesia, which can contribute to improving manure management and reduce environmental issues related to nutrient losses.

• 한국식품영양과학회지
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• 제9권1호
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• pp.1-14
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• 1980

The purpose of this study was to assess dietary intake and food habits of low-income person aged 60 years or eldary. The hundred fifty persons from the suburbs of Jeonju were surveyed between August 1 to 20,1979. Results were as follows: Family environment Approximately 90% of elderly persons surved, lived with their children and grand-children: 5.2% together as a couple; and 4.4%, widowed, lived alone. Nearly 40% of the households has a average monthly incomes of W40,000 to W100,000. Average food expediture accounted for 50 to 70% of total monthly income, thus indicating that the subject families belonged to the lowest socioeconomic level. As pocket money, 74.5% of male subjects had more than W5,100 per month. whereas, 51.4% of female had less than W5,000. Anthropometric measurements: 97.6% of subjects has heights greater than 90% of the Korean standard for their age group, whereas 45.2% of the subjects were 60 to 89% of standard weight. 88% had an arm circumferences only 60 to 89% of the standard. Nutrient intake: Intake of the majority of nutrients was below the recommended allowances, especially for energy, protein, calcium and iron. The energy input ratio of carbohydrate: protein: fat was 73.1-80.9. 13.3-15.8: 4.5-11.5, showing very heavy dependence on carbohydrates for energy needs. The contribution of animal protein was 24.3% of total protein intake, indicating an improper protein diet. Other factors influenced on the nutrient intake: Poor teeth, illness, and poor appetite were always associated with inadequate intake of energy and nutrients. The larger the family size, the lesser intake of nutrients was observed among those elderly.

• Journal of Ecology and Environment
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• 제44권4호
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• pp.212-221
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• 2020

Background: Rapid industrialization has caused various impacts on nature, including heavy metal pollution. However, the impacts of industrialization vary depending on the types of industrializing activity and surrounding environment. South Korea is a proper region because the rapid socio-economical changes have been occurred since the late nineteenth century. Therefore, in this study, we estimate the anthropogenic impacts on an ecosystem from a sediment core of Yonghwasil-mot, an irrigation reservoir on the western coast of Korea, in terms of heavy metal concentrations, nutrient influx, and pollen composition. Results: The sediment accumulation rate (SAR) determined by 210Pb geochronology showed two abrupt peaks in the 1930s and 1950s, presumably because of smelting activity and the Korean War, respectively. The following gradual increase in SAR may reflect the urbanization of recent decades. The average concentrations of arsenic (As), copper (Cu), and lead (Pb) during the twentieth century were > 48% compared to those before the nineteenth century, supporting the influence of smelting activity. However, at the beginning of the twenty-first century, the As, Cu, and Pb concentrations decreased by 19% compared to levels in the twentieth century, which is coincident with the closure of the smelter in 1989 and government policy banning leaded gasoline since 1993. The pollen assemblage and nutrient input records exhibit changes in vegetation cover and water level of the reservoir corresponding to anthropogenic deforestation and reforestation, as well as to land-use alteration. Conclusions: Our results show that the rapid socio-economic development since the twentieth century clearly affected the vegetation cover, land use, and metal pollutions.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.88-88
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• 2022

Detection of stress responses in crops is important to diagnose crop growth and evaluate yield. Also, the multi-spectral sensor is effectively known to evaluate stress caused by nutrient and moisture in crops or biological agents such as weeds or diseases. Therefore, in this experiment, multispectral images were taken by an unmanned aerial vehicle(UAV) under field condition. The experiment was conducted in the long-term fertilizer field in the National Institute of Crop Science, and experiment area was divided into different status of NPK(Control, N-deficiency, P-deficiency, K-deficiency, Non-fertilizer). Total 11 vegetation indices were created with RGB and NIR reflectance values using python. Variations in nutrient content in plants affect the amount of light reflected or absorbed for each wavelength band. Therefore, the objective of this experiment was to evaluate vegetation indices derived from multispectral reflectance data as input into machine learning algorithm for the classification of nutritional deficiency in rice. RandomForest model was used as a representative ensemble model, and parameters were adjusted through hyperparameter tuning such as RandomSearchCV. As a result, training accuracy was 0.95 and test accuracy was 0.80, and IPCA, NDRE, and EVI were included in the top three indices for feature importance. Also, precision, recall, and f1-score, which are indicators for evaluating the performance of the classification model, showed a distribution of 0.7-0.9 for each class.

• 한국토양비료학회지
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• 제43권3호
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• pp.315-321
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• 2010

시설재배는 폐쇄된 환경에서 제한적인 물관리로 인하여 작기 중에는 외부에 영향을 미치지 않으나, 작물 생산 이후 토양 중 집적된 염류를 제거하기 위해 담수처리를 하게 되는데, 이 때 토양 중 염류가 지표유출 및 용탈을 통하여 주변 수질에 영향을 직접 미치고 있어서 이에 대한 정량적인 평가를 하였다. 입지조건이 다른 두 시설재배지인 경북 상주시 서곡동에 위치한 시설하우스에서 2008년 7월 중순부터 9월 중순까지 시험 전 후의 토양 화학성, 관개량 및 관개수질, 침투수량 및 침투수질, 표면수질, 그리고 조사기간 동안 주변 하천 수질을 조사하였다. 하성평탄지에서는 담수직후의 제염률은 60.4%로 곡간지에 비해 훨씬 높았으며 76.6%까지 높아졌다가 담수 20일 후에는 66.7%이었다. 담수초기부터 곡간지의 표면수중 $NH_4$-N과 $PO_4$-P 농도가 하성평탄지보다 높았으며, 곡간지에서 담수직후와 담수종료 후의 토양깊이별 $Cl^-$과 ${SO_4}^{2-}$ 농도는 큰 차이가 있었으나, 하성평탄지에서는 토양깊이별 ${SO_4}^{2-}$ 농도만 차이가 있었다. 침투수중 $NO_3$-N 농도 변화는 곡간지에 비해 하성평탄지에서 변화의 폭이 컸으며, 시간이 경과할수록 그리고 토양이 깊어질수록 그 농도도 높았다. 또한, 곡간지와 하성평탄지에 있는 시설재배지에서 담수제염에 의한 질소와 인수지를 비교 평가해 본 결과 곡간지와 하성평탄지 모두 유입 부하량보다 유출 부하량이 많아 외부 수계의 영향을 주는 것으로 평가되었다. 특히, 곡간지에 비해 하성평탄지에서의 양분 부하량이 더 많은 것으로 평가되었는데, 곡간지에서는 지하용탈만으로 제염을 하여 지하수의 수질에 영향을 주고 하성평탄지에서는 지하용탈뿐만 아니라 지표용탈에 의한 제염으로 인해 하천수의 수질에 영향을 주는 것으로 평가되었다.

• 한국토양비료학회지
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• 제43권4호
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• pp.458-465
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• 2010

가축분 퇴비 시용 수준에 따른 수수${\times}$수단그라스 ($S{\times}S$ hybrid)의 수량 및 양분 (N, P)흡수 변이를 조사하기 위해 전남대학교 부속 농장 초지에서 3반복 난괴법으로 실험을 실시하였다. 6개 처리 (무비구, 화학비료관행구, 퇴비 1, 2, 4, 6 수준)를 두었는데, 화학비료관행구의 비료 처리량은 질소 20 g N $m^{-2}$과 인산 20 g $P_2O_5\;m^{-2}$이고, 가축분 퇴비는 6 수준을 기준시비량 (20.2 g N $m^{-2}$과 21.6 g $P_2O_5\;m^{-2}$)으로 두고 퇴비 1, 2, 4 수준은 그 비율대로 감비하였다. 처리 90일 후 최종 지상부 건물중과 양분 (N, P) 흡수량을 조사하였다. 화학비료 처리구의 건물중 (2.4 kg $m^{-2}$)과 질소 (38.3 g N $m^{-2}$) 및 인산 (15.3 g $P_2O^5\;m^{-2}$) 흡수량이 가장 높았으며, 퇴비 시용량이 증가함에 따라 건물중과 양분 흡수량이 증가하는 경향을 보였다 (P<0.01). 하지만, 퇴비 4와 6 수준의 건물중은 각각 1.9 kg $m^{-2}$과 1.8 kg $m^{-2}$으로 차이가 없었다. 따라서, 가축분 퇴비 단독 시비로는 화학비료와 대등한 건물 생산이 어려울 것으로 판단되었다. 양분흡수효율 분석 결과에 의하면 퇴비의 인산흡수 효율이 화학비료보다 높았기 때문에, 퇴비를 인산 급원으로 시용하고 부족한 질소는 농가의 비료자원 수급 가능성과 목표 수량을 고려하여 액비, 화학비료, 녹비 등으로 공급하는 것이 적절한 시비 전략으로 판단된다.