• Parasites, Hosts and Diseases
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• 제34권1호
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• pp.79-86
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• 1996

형태적으로 Aconaqmoebcusteuon리로 동정된 한국토양분리주 KA/S2의 일부 특성을 파악하여 A. castellanii로 알려진 4가지 reference 주(Castellani, Neff, fna 및 Chang주) 와 비교하였다 K4/s2주의 mitochondria(Mt) DNARFLP와 isoelectricforusing(IEF)로 분석한 동위효소 양상은 California 토양에서 분리된 Neff주의 그것과 동일하였으나 고 외의 주들 사이에는 심한 다양성이 과찰되었다. Chang주의 형태 및 전 단백질 양상은 다른 주에 비해 독특하였다. Aconamoeba app. 분리주의 동정 및 특성 파악에 Mt DNA RFLP 분석이 매우 유용할을 확인하였다. Aconamoebacasteunil의 우리말 학명을 카스텔라니가시아메바로 제안한다.

• 한국균학회지
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• 제45권1호
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• pp.83-89
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• 2017

전북 전주시 완산구의 토양으로부터 국내 미기록종인 균류를 분리하였다. 형태학적 특징 및 ITS영역, ${\beta}-tubulin$, $EF1-{\alpha}$ 유전자를 이용한 계통학적 분석 결과, 토양에서 분리한 균류는 Diaporthe tectonae인 것으로 확인되었으며, 본 연구를 통해 D. tectonae가 국내에 존재함을 최초로 보고하였다.

• 한국토양비료학회지
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• 제48권5호
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• pp.351-360
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• 2015

Human influence on soil formation has dramatically increased with human civilization and industry development. Increase of anthropogenic soils induced researches on the anthropogenic soils; classification, chemical and physical characteristics of anthropogenic soils and plant growth from anthropogenic soils. However there have been no comprehensive analyses on soil pore or physical properties of anthropogenic soils from 3 dimensional images in Korea. The objectives of this study were to characterize physical properties of anthropogenic paddy field soils by depth and to find differences between natural and anthropogenic paddy field soils. Soil samples were taken from two anthropogenic and natural paddy field soils; anthropogenic (A_c) and natural (N_c) paddy soils with topsoil of coarse texture and anthropogenic (A_f) and natural (N_f) paddy soils with topsoil of fine texture. The anthropogenic paddy fields were reestablished during the Arable Land Remodeling Project from 2011 to 2012 and continued rice farming after the project. Natural paddy fields had no artificial changes or disturbance in soil layers up to 1m depth. Samples were taken at three different depths and analyzed for routine physical properties (texture, bulk density, etc.) and pore properties with computer tomography (CT) scans. The CT scan provided 3 dimensional images at resolution of 0.01 mm to calculate pore radius size, length, and tortuosity of soil pores. Fractal and configuration entropy analyses were applied to quantify pore structure and analyze spatial distribution of pores within soil images. The results of measured physical properties showed no clear trend or significant differences across depths or sites from all samples, except the properties from topsoils. The results of pore morphology and spatial distribution analyses provided detailed information of pores affected by human influences. Pore length and size showed significant decrease in anthropogenic soils. Especially, pores of A_c had great decrease in length compared to N_c. Fractal and entropy analyses showed clear changes of pore distributions across sites. The topsoil layer of A_c showed more degradation of pore structure than that of N_c, while pores of A_f topsoil did not show significant degradation compared with those of N_f. These results concluded that anthropogenic soils with coarse texture may have more effects on pore properties than ones with fine texture. The reestablished paddy fields may need more fundamental remediation to improve physical conditions.

• 한국초지조사료학회지
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• 제20권2호
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• pp.131-138
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• 2000

This experiment was carried out during the period from September, 1997 to October, 1998 to determine the effect of fermented saw-dust pig manure (FSP) application on the herbage production on a mixed pasture in the Cheju brown volcanic ash soil. Split plot design (main plot: 3 nitrogen application levels of 0, 150 and 300 kgiha; sub plot: 4 pig sawdust manure levels of 0, 3, 6 and 12 tonha) was used. Plant height and dry matter yield increased significantly with an increase of nitrogen and FSP level. There was no difference in the botanical composition of grasses as affected by FSP application level, but herbage yields of grass species were increased by nitrogen application compared to that without nitrogen application. Botanical composition of white clover decreased with an increase of nitrogen application, but increased with an increase of FSP application level. Percentages of weeds were not affected by application rates of chemical nitrogen fertilizer and swine manure in the mixed species pasture. Nitrogen, phosphorus, and potassium contents of species in the pasture significantly increased with increasing application rates of nitrogen fertilizer. In conclusion, it would be an optimum to apply 150 kgha of inorganic chemical fertilizer and plus either 3 or 6 toniha of fermented swine manure with sawdust for optimum production of mixed pasture on Cheju Island. (Key words : Herbage production, Botanical composition, Morphology, Plant mineral contents)

• Geomechanics and Engineering
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• 제14권4호
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• pp.307-314
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• 2018

Strength of loess that experienced cyclic freeze and thaw is of great significance for evaluating stability of slopes and foundations in loess regions. This paper takes the frequently encountered loess in the Northwestern China as the study object and carried out three kinds of laboratory tests including freeze-thaw test, direct shear test and SEM test to investigate the strength behaviors of loess after cyclic freeze and thaw, and the correlation with meso-level changes in soil structure. Results show that for loess specimens at four dry densities, the cohesion decreases with freeze-thaw cycles until a residual value is reached and thus an exponential equation is proposed. Besides, little change in the angle of internal friction was observed as freeze-thaw proceeds. This may depend on the varying of soil structure, based on which a clue can be found from the surface morphology and mesoscopic scanning of loess specimens. Clearly we observed significant changes in surface morphology of loess and it tends to aggravate at higher water contents or more cycles of freeze and thaw. Moreover, freeze-thaw cycling leads to obvious changes in the meso-structure of loess including lowering the particle aggregates and increasing both the proportion of fine particles and porosity area ratio. A damage variable dependent on the ratio of porosity area is introduced based on the continuum damage mechanics and its correlation with cohesion is discussed.

• 한국토양비료학회지
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• 제3권1호
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• pp.61-66
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• 1970

홍적(洪積)에 기인(基因)된 적황색토중(赤黃色土中) 생성년대(生成年代)가 오래다고 추정(推定)되는 창평통(昌平統)에 대한 형태(形態) 및 물리적(物理的) 화학적(化學的) 성질(性質)에 관(關)하여 조사(調査)한 결과(結果)를 요약(要約)하여 보면 다음과 같다. 형태적특성(形態的特性)에 있어 표토(表土)(A층(層))는 암갈색(暗褐色)의 미사질식양토(微砂質埴壤土)이며 심토(心土)(B층(層))는 암적색(暗赤色) 내지(乃至) 적색(赤色)의 미사질식토(微砂質埴土) 혹은 식토(埴土)로서 토괴표면(土塊表面)에 점토피막(粘土皮膜)이 형성(形成)되어 있다. 기층(基層)은 풍화(風化)된 석력(石礫)이 있는 홍적모재(洪積母材)이며 토양(土壤)의 깊이는 150cm 이상(以上)으로 매우 깊다. 물리적(物理的) 화학적(化學的) 특성(特性)에 있어서는 강산성(强酸性)(표토(表土) 4.5 심토(心土) 5.2~5.5)이며 유기물함량(有機物含量)(표토(表土) 0.84% 심토(心土) 0.15~0.8%)이 낮음과 동시(同時) 염기치환용량(鹽基置換容量)(표토(表土) 12me/100g 심토(心土) 8.9~23.5me/100g)도 낮다. 그러나 치환침출염류(置換浸出鹽類) 총량(總量)에 의(依)한 염기포화도(鹽基飽和度)(표토(表土) 55% 심토(心土) 48~85%)는 비교적(比較的) 높은 편(便)이다. 토양입자(土壤粒子)의 수직분포(垂直分布)에 있어서 표토(表土) 및 심토(心土)는 뚜렷한 변화(變化)가 없는 것으로 보아 심토(心土)에 있어 점토집적(粘土集積)은 Podzolization에 의(依)한 것이라기 보다 점토(粘土)의 기계적이동(機械的移動)에 의(依)한 것이라 추정(推定)된다. 창평통(昌平統)은 USDA 7차분류시안(次分類試案)에 의(依)하면 Typic Hapludalfs, FAO 분류방식(分類方式)에 의(依)하면 Brunic Luvisols 에 속(屬)한다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.145-152
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• 2005

Landslides triggered by rainfall produces severe effects on the serviceability and stability of railway operation. Since small amount of soil mass slipped on the rail can cause derailment which will cause severe danger on the human and trains, slope stability problem is one of the major concerns on the operation of railway. In this study we investigate the some of characteristics of rainfall driven landslide near railroad. A total of 23 sites were visited. From the results four types of landslides based upon the morphology of the slipped slope triggered by rainfall were classified. From the analysis dimensions of slopes (height, length and slope) do not show particular correlation with the types of landslides. In addition, morphological and geological features of slope influence on the occurrence of different types of landslides.

• 한국의류산업학회지
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• 제15권2호
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• pp.302-308
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• 2013

This study is a preliminary investigation of the influence of surface characteristics of substrates on detergency of particulate soil. The surface of PET film was modified with NaOH and NaOH+ethylene diamine on different times. The surface morphology of the film was scanned by AFM and surface energies were calculated from measured contact angles between several solutions and film based on the geometric mean and a Lewis acid base method. The surface morphology of PET film treated with NaOH and NaOH+ethylene diamine became more etched, and the surface area, surface roughness and the coefficient of friction of film increased with treatment of NaOH and NaOH+ethylene diamine. The contact angle of film treated with NaOH and NaOH+ethylene diamine decreased in water and surfactant solution; in addition, the surface energy increased was largely attributed to the increased portion on the polar surface energy of film. However, the effect of the diamine addition to the NaOH treatment solution on surface characteristics of PET film was insignificant.

• Geomechanics and Engineering
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• 제31권3호
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• pp.281-289
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• 2022

Bio-CaCO₃ is a blowout environment-friendly materials for soil improvement and sealing of rock fissures. To evaluate the chemical characteristics, shape, size and productivity of soybean urease induced CaCO₃ precipitates (SUICP), experimental studies were conducted via EDS, XRD, FT-IR, TGA, BET, and SEM. Also, the conversion rate of SUICP reaction at different time were determined and analyzed. The Bio-CaCO₃ product obtained by SUICP is comprehensively judged as calcite based on the results of EDS, XRD and FT-IR. The SUICP calcite precipitates are detected as spherical or ellipsoidal particles 3-6 ㎛ in diameter with nanoscale pores on their surface, and this morphology is novel. The median secondary particle size d₅₀ is 39-88 ㎛, indicating the agglomeration of the primary calcite particles. The Bio-calcite decomposes at 650-780℃, representing a medium thermal stability. The conversion rate of SUICP reaction can reach 80% in 24h, which is much more efficient than microbially induced CaCO₃ precipitation. These results reveal the knowledges of SUICP, and further direct its engineering applications. Moreover, we show an economic channel to obtain porous spherical calcite.

• Journal of Biosystems Engineering
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• 제39권4호
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• pp.377-388
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• 2014

Purpose: Determining the spatial structure of data is important in understanding within-field variability for site-specific crop management. An understanding of the spatial structures present in the data may help illuminate interrelationships that are important in subsequent explanatory analyses, especially when site variables are correlated or are a combined response to multiple causative factors. Methods: In this study, correlation, principal component analysis, and single and nested variogram models were applied to soil electrical conductivity and chemical property data of two fields in central Missouri, USA. Results: Some variables that were highly correlated, or were strongly expressed in the same principal component, exhibited similar spatial ranges when fitted with a single variogram model. However, single variogram results were dependent on the active lag distance used, with short distances (30 m) required to fit short-range variability. Longer active lag distances only revealed long-range spatial components. Nested models generally yielded a better fit than single models for sensor-based conductivity data, where multiple scales of spatial structure were apparent. Gaussian-spherical nested models fit well to the data at both short (30 m) and long (300 m) active lag distances, generally capturing both short-range and long-range spatial components. As soil conductivity relates strongly to profile texture, we hypothesize that the short-range components may relate to the scale of erosion processes, while the long-range components are indicative of the scale of landscape morphology. Conclusion: In this study, we investigated the effect of changing active lag distance on the calculation of the range parameter. Future work investigating scale effects on other variogram parameters, including nugget and sill variances, may lead to better model selection and interpretation. Once this is achieved, separation of nested spatial components by factorial kriging may help to better define the correlations existing between spatial datasets.