• 한국약용작물학회지
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• 제23권5호
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• pp.351-356
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• 2015

Background : Ginseng is mainly grown as a break crop in paddy fields after rice has been cultured for approximately 4 - 5 years, because it reduces the negative effects of continuous rice cropping. However, physiological disorders, such as leaf discoloration, occur in ginseng grown in paddy fields with poor drainage and excessive levels of inorganic components. Methods and Results : This study investigated the effect of ridge height on the growth characteristics and yield of 6 year old Panax ginseng. Ridge height was varied by making 20, 30, and 40 cm high ridges in a pooly drained paddy field. Soil moisture content decreased, while electrical conductivity (EC) as the ridge height increased. The $NO_3$, K, Ca, Mg, and Na levels also rose as ridge height increased, but organic matter and $P_2O_4$ levels did not. The leaf discoloration ratio rose as the ridge height increased, and root yield reached a peak when the ridge height was 30 cm. Conclusion : A ridge height of 30 cm in poorly drained paddy field improved ginseng growth by reducing leaf discoloration and increasing root survival, owing to more suitable soil moisture and EC levels.

• 한국수산과학회지
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• 제27권1호
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• pp.97-105
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• 1994

금강 하구에서 관찰되는 황색 수색대의 발생 원인과 성상을 규명하기 위하여 92년 5월, 7월, 8월, 10월, 93년 2월 금강 하구해역 18개 정점에서 행한 연구 조사 결과를 요약하면 금강 하구 해역에 나타나는 황색 수색대의 수색은 수색계급 9에 해당되며 보통 조사점 1, 2, 3, 4, 5, 7, 8, 9, 13, 14, 15 및 17에서 연중 계속 존재하였다. 금강하구 해역의 일반수질은 해역환경기준 I 등급에 해당하는 양호한 상태이나 유기오염물은 증가되고 있으며 영양염 농도는 황색 수색대 안쪽 해역이 바깥쪽 해역보다 높은데 총무기질소 안쪽 해역에서 보면 총무기질소는 해역환경기준 III등급을 초과하였고 인산인 농도는 III등급이었으며 바깥쪽 해역에서는 총무기질소 농도와 인산인 농도 모두 II등급에 해당하는 부영양 상태였다. 그러나 금강하구 해역은 유속이 빠르고 총부유물질로 인한 광투과 저하 때문에 식물성 프랑크톤의 대량증식에는 부적합한 지역이었다. 또한, 금강하구 해역에 나타나는 황색 수색대의 형성 원인 총부유물질 중 $85\%$ 이상을 점유하는 토사때문이었다.

• Journal of Plant Biology
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• 제15권3호
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• pp.1-8
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• 1972

A comparison between the productivity of the evergreen needle pine(Pinus densiflora) and of the deciduous broad leaved oak(Quercus mongolica) stands, which is located near Choon-Chun city, Kangwon dist. have been established. The pine stand had a stand density of 938 trees per ha and oak stand had of 638 trees per ha. The diameter at breast height (D) and the height of tree (H) of each tree were measured in sample plot of 800$m^2$. Twelve standard sample trees chose from the sample area felled down, and then weighed the stem, branches and leaves separately, according to both the stratified clip technique and the stem analysis. The vertical distribution of photosynthetic system was arranged effectively for high productivity in the productive structure of both trees. The allometric relation between D2H and dry weight of stem (Ws), branches (Wb) and leaves (Wl) of pine were approximated by log Ws=0.6212 log D2H-0.5383 log Wb=0.4681 log D2H-0.7236 log Wl=0.2582 log D2H-5.1567 and those of oak were approximated by log Ws=0.5125 log D2H＋0.0231 log Wb=0.5125 log D2H-0.3755 log Wl=0.8721 log D2H-2.9710 From the above, the standing crops of pine and oak in the sample area were estimated to be as much as 38.83ton and 48.11 ton of dry matter, above ground, per ha, respectively. Annual net production as the sum of the biomass newly formed during one year was appraised at 12.66ton/ha.yr in pine stand and at 8.74 ton/ha.yr in oak. The reason of high productivity of pine stand compared with oak might be resulted from much more about 4 times of the amount of the photosynthetic system, but less non-photosynthetic one of pine than those of oak. To increase the productivity of the forest stands investigated it was necessary to make densly a stand density, to be abundant in the inorganic nutrients and to preserve much water in soil to conserve the litters.

• 한국환경과학회지
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• 제15권1호
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• pp.21-31
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• 2006

Aquatic plants grow in water with photosynthesis and purify water quality as taking organic and inorganic matter in water. Polluted water in stagnant stream channel where nutritive salts load is great can be purified by activities of aquatic plants. Aquatic plants should be fixed to bed easily to plant and sustainable environment is needed. So in this study, Mattress/Filter system is suggested to plant aquatic plant in stagnant stream channel. In the result of study, coverage of Phragmites australis, Zizania latifolia and Typha angustifolia which planted in mattress was $78\%,\;62\%\;and\;82\%$ and numbers of species in each mattress system were 7, 11, 3. The evenness index of each mattress system was 0.86, 0.91 and 0.79 and diversity index of each mattress system was 1.67. 2.18 and 0.87. Removal rates of phosphorus at Phragmites australis, Zizania latifolia and Typha angustifolia which planted in mattress were $68.7\%,\;62.7\%,\;55.3\%$ and removal rates of nitrogen of them were $79.8\%,\;74.7\%,\;64.9\%$. The removal rate of nitrogen was greater than phosphorus at all system and both removal rates were greater at Phragmites australis than at Zirania latifolia and at Typha angustifolia the rate was the least. Removal rates of $PO_4^{-3},\;NH_4-N,\;NO_{3-}N$ at Phragmites australis were $57.4\%,\;52.8\%,\;47.8\%$ and at Zizania latifolia were $82.6\%,\;77.2\%,\;67.5\%$ and at Typha angustifolia were $80.6\%,\;73.7\%,\;64.3\%$. It seems that removal effect is great by the planted mattress system.

• Environmental Engineering Research
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• 제24권1호
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• pp.159-172
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• 2019

To investigate the influence of pollution events on the chemical composition and formation processes of aerosol particles, 24-h integrated size-segregated particulate matter (PM) was collected during the fall season at an urban site of Gwangju, Korea and was used to determine the concentrations of mass, water-soluble organic carbon (WSOC) and ionic species. Furthermore, black carbon (BC) concentrations were observed with an aethalometer. The entire sampling period was classified into four periods, i.e., typical, pollution event I, pollution event II, and an Asian dust event. Stable meteorological conditions (e.g., low wind speed, high surface pressure, and high relative humidity) observed during the two pollution events led to accumulation of aerosol particles and increased formation of secondary organic and inorganic aerosol species, thus causing $PM_{2.5}$ increase. Furthermore, these stable conditions resulted in the predominant condensation or droplet mode size distributions of PM, WSOC, $NO_3{^-}$, and $SO{_4}^{2-}$. However, difference in the accumulation mode size distributions of secondary water-soluble species between pollution events I and II could be attributed to the difference in transport pathways of air masses from high-pollution regions and the formation processes for the secondary chemical species. The average absorption ${\AA}ngstr{\ddot{o}}m$ exponent ($AAE_{370-950}$) for 370-950 nm wavelengths > 1.0 indicates that the BC particles from traffic emissions were likely mixed with light absorbing brown carbon (BrC) from biomass burning (BB) emissions. It was found that light absorption by BrC in the near UV range was affected by both secondary organic aerosol and BB emissions. Overall, the pollution events observed during fall at the study site can be due to the synergy of unfavorable meteorological conditions, enhanced secondary formation, local emissions, and long-range transportation of air masses from upwind polluted areas.

• 한국입자에어로졸학회지
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• 제17권3호
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• pp.43-54
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• 2021

Size distributions of atmospheric particulate matter (PM) and its water-soluble organic and inorganic components were measured between January and February 2021 at an urban site in Gwangju in order to identify the major factors that determine their size distributions. Their size distributions during the study period were mainly divided into two groups. In the first group, PM, NO₃^-, SO₄^2-, NH₄⁺ and water-soluble organic carbon (WSOC) exhibited bi-modal size distributions with a dominant condensation mode at a particle size of 0.32 ㎛. This group was dominated by local production of secondary water-soluble components under atmospheric stagnation and low relative humidity (RH) conditions, rather than long-range transportation of aerosol particles from China. On the other hand, in the second group, they showed tri-modal size distributions with a very pronounced droplet mode at a diameter of 1.0 ㎛. These size distributions were attributable to the local generation and accumulation of secondary aerosol particles under atmospheric conditions such as atmospheric stagnation and high RH, and an increase in the influx of atmospheric aerosol particles by long-distance transportation abroad. Contributions of droplet mode NO₃^-, SO₄^2-, NH₄⁺ and WSOC to fine particles in the second group were significantly higher than those in the first group period. However, their condensation mode contributions were about two-fold higher in the first group than in the second group. The significant difference in the size distribution of the accumulation mode of the WSOC and secondary ionic components between the two groups was due to the influx of aerosol particles with a long residence time by long-distance transport from China and local weather conditions (e.g., RH).

• 농업과학연구
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• 제47권4호
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• pp.1021-1027
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• 2020

The amount of food waste generated in Republic of Korea has been increasing alongside an increasing population and booming economy as such, research on effective treatment and recycling is required. Food waste recycling is complicated by its inferior characteristics such as high levels of water and concern that its continuous application to farmland can lead to salt accumulation and concomitant damage crops. In the present study, therefore, dehydrated food waste powder (FWP), which contains a large amount of organic matter and nutrients, but which may require additional improvements was mixed in various ratios with organic fertilizers and the mixtures were tested for their effects on the growth of the leaf lettuce. A control was set up with inorganic fertilizers alone while a treatment with only FWP was also included. The mixture of FWP and organic fertilizers produced better leaf lettuce growth in all the treatments than the control and FWP. The fresh weight of the leaf lettuce produced with a mixture containing 60% FWP was 50% higher than that of the control. The results from this study indicate, therefore, that FWP mixed with other organic supplements in appropriate amounts positively impacts crop growth and development.

• 한국환경과학회지
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• 제30권3호
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• pp.195-206
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• 2021

Contaminated marine sediment is a secondary pollution source in the coastal areas, which can result in increased nutrients concentrations in the overlying water. We analyzed the nutrients release characteristics into overlying water from sediments and the interaction among benthic circulation of nitrogen, phosphorus, iron, and sulfur were investigated in a preset sediment/water column. Profiles of pH, ORP, sulfur, iron, nitrogen, phosphorus pools were determined in the sediment and three different layers of overlying water. Variety types of sulfur in the sediments plays a significant role on nutrients transfer into overlying water. Dissimilatory nitrate reduction and various sulfur species interaction are predominantly embodied by the enhancing effects of sulfide on nitrogen reduction. Contaminant sediment take on high organic matter, which is decomposed by bacteria, as a result promote bacterial sulfate reduction and generate sulfide in the sediment. The sulfur and iron interactions had also influence on phosphorus cycling and released from sediment into overlying water may ensue over the dissolution of ferric iron intercede by iron-reducing bacteria. The nutrients release rate was calculated followed by release rate equation. The results showed that the sediments released large-scale quantity of ammonium nitrogen and phosphate, which are main inner source of overlying water pollution. A mechanical migration of key nutrients such as ammonia and inorganic phosphate was depicted numerically with Fick's diffusion law, which showed a fair agreement to most of the experimental data.

• 한국물환경학회지
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• 제37권6호
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• pp.442-448
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• 2021

Seawater desalination is a technology through which salt and other constituents are removed from seawater to produce fresh water. While a significant amount of fresh water is produced, the desalination process is limited by the generation of concentrated brine with a higher salinity than seawater; this imposes environmental and economic problems. In this study, characteristics of seawater from three different locations in South Korea were analyzed to evaluate the feasibility of crystallization to seawater desalination. Organic and inorganic substances participating in crystal formation during concentration were identified. Then, prediction and economic feasibility analysis were conducted on the actual water flux and obtainable salt resources (i.e. Na2SO4) using membrane distillation and energy-saving crystallizer based on multi-stage flash (MSF-Cr). The seawater showed a rather low salinity (29.9~34.4 g/L) and different composition ratios depending on the location. At high concentrations, it was possible to observe the participation of dissolved organic matter and various ionic substances in crystalization. When crystallized, materials capable of forming various crystals are expected. However, it seems that different salt concentrations should be considered for each location. When the model developed using the Aspen Plus modular was applied in Korean seawater conditions, relatively high economic feasibility was confirmed in the MSF-Cr. The results of this study will help solve the environmental and economic problems of concentrated brine from seawater desalination.

• 아시안잔디학회지
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• 제18권3호
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• pp.149-163
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• 2004

Putting green을 골프장 전체 면적의 $2\%$로 작은 면적이지만 green의 건강한 상태는 골프장의 성공여부를 좌우한다. 이 실험은 University of Missouri-Columbia, Turfgrass Research Center에서 어느 putting green root zone 구조와 토양 개량제가 가장 건강하고 최적의 putting green조건을 유지하는가를 비교하기 위하여 1999년 6월부터 2002년 12월까지 실행되어졌다. California putting green root zone system(30츠의 $100\%$ 모래층 밑에 13cm silt loam 토양층)은 특히 putting green을 가격을 줄일 수 있으며 배수가 잘되고 공기 순환에 있어서는 좋은 조건이지만 낮은 수분 보존량과 잔디에 공급되어지는 영양분이 낮은 것으로 조사 되어지고 있다. USGA(United States Golf Association) putting green root zone system [30cm의 $90\%$ 모래와 $10\%$ Peatmoss (organic material; 유기물) 혼합물층 밑에 13cm 자갈층]은 California system($100\%$ 모래)의 단점을 보완할 수 있지만 년수가 지남에 따라 문제점이 발견되어졌다. 시간의 흐름에 따른 organic matter의 축적과 분해 그리고 잦은 잔디관리 장비의 운행과 player들의 발자국에 의한 green compaction(압축)의 증가가 putting green에서의 수분 침투량(Infiltration rate)과 공기순환을 방해하며 이로인해 잔디의 생장을 저해하며 green의 질은 낮게 만든다. Putting green root zone mixtures에서의 유기물질인 peatmoss사용에 비해 Zeolite와 같은 무기물질의 사용이 토양 물리적, 생리적 특성에 있어 우수함이 조사되어지고 있다. 년수가 지날수록 증가하는 USGA green($10\%$ Peatmoss)의 단점 (organic matter의 축적과 분해 증가, 수분 침투력과 공기순환 감소, 높은 수분함량)에 비해 $10-15\%$ Zeolite(무기물)의 사용이 보다나은 putting green 물리적, 생리적 조건들을 오래토록 유지할 수 있으며 건강한 잔디상태를 보존할 수 있을 것이다. 이 시험은 수정된 Modified California putting green root zone system [25cm의 $85\%$ 모래와 $15\%$ Zeolite(inorganic material ; 무기물) 혼합물층 밑에 18cm silt loam 토양층]이 California와 USGA green system과 비교할 때 보다나은 putting green 조건을 유지하는가를 위해 조사되어졌다. 수정된 Modified California green system이 건강한 putting green을 유지하기 위한 우수한 물리적 조건(높은 수분 침투력과 수분 함량, 낮은 토양밀도)과 생리적 조건(높은 양이온 교환력과 유효 식물영양분 함량)을 가지고 있음이 조사되어졌다. 또한 우수한 putting green 잔디품질을 이 실험 기간동안 유지하였다. 결론적으로 California system($100\%$ 모래)에 $15\%$의 무기물질(Zeolite)이 첨가되어진 Modified California putting green system이 최적의 putting green 조건과 우수한 Bentgrass 잔디품질을 4년 동안 유지하였음을 이 실험을 통해 조사되어졌다.