• Korean Journal of Soil Science and Fertilizer
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• v.30 no.3
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• pp.234-241
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• 1997

The effects of bulk densities(${\rho}_b$) on saturated hydraulic conductivity (Ksat) and solute elution patterns were investigated from five different bulk densities ranging from $1.1Mg/m^3$ to $1.5Mg/m^3$ with each increment of $0.1Mg/m^3$. The hydraulic conductivities observed were divided into two stages: (1) a linearly decrease with increase in bulk density up to $1.4Mg/m^3$, (2) a steady state where the bulk density is greater than $1.4Mg/m^3$. Using the saturated hydraulic conductivity at the steady state, we figured out the equation describing the correlation between bulk densities(${\rho}_b$) and saturated hydraulic conductivity(Ksat) as follows: $Ksat=-19.2({\rho}_b{^2})+6{\rho}_b+15.5$, (r=0.985). Electrical conductivity(EC) measured from the leachate of the soil column showed that EC at the same pore volume were decreased with an increase in the bulk density from $1.2g/cm^3$, $1.5g/cm^3$, as shown in the time taken to collect the same pore volume at each respective bulk density. The maximum relative concentrations (C/Co=1) from the breakthrough curves for the anions of $Cl^-$, $NO_3{^-}$ and $SO_4{^{2-}}$, which are weakly adsorbed on the soil particles, moved to the right of the graph, while a distinctive retardation occurs at the bulk density between $1.3Mg/m^3$ and $1.4Mg/m^3$. The time taken to recover about 90% of indigenous sulphate was approximately twice as those of chloride and nitrate, resulting in slightly stronger adsorption characteristics for sorption sites on the soil surface. Thus, we can conclude that the salt accumulation in green house soil might be significantly influenced by it's bulk density at the soil depth, as well as the adsorption capacity of ions for the sorption sites in soils.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.1
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• pp.46-50
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• 1997

This study was conducted to find out the main soil physical properties to control the soil hardness in tamped condition. Sandy loam soil was taken and fill it up to wood cubes and then differently trampling experimental cubic lots which were mulched with various materials, such as, leaves, wood plates and bricks. Soil physical properties were measured 2" core and samples were taken at 250 sites with soil hardness. There were highly significant positive correlations between soil hardness and bulk density, and between bulk density and water content. Negative correlations were found between soil hardness and water content, and between soil hardness and gravel content. The correlation coefficients were increased by multiple correlation between soil hardness, bulk density, volumetric water and gravel content. Bulk density was the main factor to control the hardness, and volumetric water and gravel contents were less effected to soil hardness.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.3
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• pp.226-233
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• 1997

To investigate the salt accumulation in the plastic film house soils, bulk density, electrical conductivity(EC), exchangeable canons and water soluble anions were determined at different depths(0~60cm) in the salt-accumulated plastic film house soils in Yesan, Chungnam, Korea. Bulk density were increased from $1.2Mg/m^3$ to $1.5Mg/m^3$ as the depth changed from 0cm(top soil) to 30cm(subsoil) below the soil surface, whereas the bulk densities between 30cm to 60cm slightly decreased to $1.42Mg/m^3$. These changes of soil bulk densities might influence the porosity and pore size distribution, resulting in affecting the water flow throughout, soil layers. Electrical conductivity and Exchangeable sodium percentage(ESP) for 0 to 10cm soil layer were 5.08 dS/m and 6.4, respectively, while the EC was decreased to less than 1.63 dS/m in 20~30cm depth and about 0.7 dS/m. Salt accumulation patterns in the plastic film house soils might be influenced by the changes of the bulk densities in soil.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.3
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• pp.221-227
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• 1989

This study was conducted to understand the influence of soil compaction on root growth and nutrient uptake characteristics of the soybean roots grown in two soils with different texture. Tap root elongation was measured on young seedling grown in cores compacted to different bulk densities of 1.2, 1.4 and $1.6/cm^3$ with different soil water retention in laboratory. The soil used were Samgag sandy loam and Baegsan loam soils. The wet and dry weight, total length, average radius and total surface area of roots were measured on soybean plants grown in 1/5000 a Wagner pots compacted to different bulk density of 1.2 and $1.4g/cm^3$. The nutrient uptake of soybean shoot was measured and evaluated with the unit surface area of roots at the 7th, 17th and 27th days after germination. The results were as follows: 1. The tap root elongation rate was faster in the loam soil with low bulk density than in the sandy loam soil with high bulk density. The elongation rates were remarkedly decreased when soil water was lower than the retention of 4 bars in loam soil and that of 1 bars in sandy loam soil. 2. Tap root elongation rate sharply decreased as increased soil strength higher than $2kgf/cm^2$ measured by ELE penetrometer showing curvillinear regression. However, it was low regardless of soil strength when soil water retention was 10 bars in sandy loam soil. 3. From the pot experiment, the total length of roots were longer in loam soil than in sandy loam soil and was longer in the soils with lower bulk density. The average radius of fine roots grown in sandy loam soil was larger than that grown in loam soil. The total surface area of roots was greater in the loam soil with low bulk density than in the sandy loam soil with high bulk density as the total length of roots. 4. The amounts of nutrient uptake by soybean shoots were greater in loam soil primarily due to more production of dry matter than in sandy loam soil. The nitrogen influx rates through the unit surface area were 597 to $753nmoles/day-cm^2$ in loam soil and 222 to $365nmoles/day\;cm^2$ in sandy loam soilshowing higher value in higher bulk density. The potasium influx rates were 99 to $175nmoles/day-cm^2$, and those of phosphate were 26 to $46nmoles/day\;cm^2$. Those of Ca and Mg were 175 to 246 and 163 to $205nmoles/day\;cm^2$. The difference in nutrient influx rates between bulk densities of these elements were lower than that of nitrogen.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.24-27
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• 2006

16개 기상관측소에서 채취한 토양 시료에 대한 토양 물성 및 열특성를 측정하였으며 이를 통하여 공극률, 함수비, 충적밀도, 입도 분포, 유기물 함량, 토양구성광물의 종류 및 함량이 열전도도에 미치는 영향을 파악하였다. 상관성 분석결과 입도분포, 유기물함량 및 토양 구성광물의 종류 및 함량은 낮은 상관성을 보였으며 용적밀도 $(R^2=0.60)$, 함수비$(R^2=0.54)$와 공극률$(R^2=0.56)$은 높은 상관성을 보였다. 또한 함수비(2%)와 토양의 종류에 따른 다중회귀 분석을 통하여 토양의 열전도도를 추정할 수 있는 회귀식을 제시하였다.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.6
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• pp.50-59
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• 2014

This experiment was performed in order to study the relationship between physical properties of soil and the growth characteristics of Sedum reflexum. A correlation analysis and multiple regression analysis were performed using SPSS Ver 19.0 for Windows. The multiple regression analysis results of soil physical properties and growth characteristics were as follows. The regression equation: The length=$.993-14.070^*$(soil bulk density)+$.233^*$(solid phase)+$.038^*$(liquid phase)+$.068^*$(permeability). The significance of soil bulk density and solid phase was great. The width=$2.931-33.925^*$(soil bulk density)+$.566^*$(solid phase)+$.206^*$(liquid phase)+$.027^*$(permeability). The significance of soil bulk density and solid phase was great. The wet weight and dry weight of the upper and lower and soil physical properties did not have a direct relationship.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.344-352
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• 2012

Soil physical properties determine soil quality in aspect of root growth, infiltration, water and nutrient holding capacity. Although the monitoring of soil physical properties is important for sustainable agricultural production, there were few studies. This study was conducted to investigate the condition of soil physical properties of arable land according to land use across the country. The work was investigated on plastic film house soils, upland soils, orchard soils, and paddy soils from 2008 to 2011, including depth of topsoil, bulk density, hardness, soil texture, and organic matter. The average physical properties were following; In plastic film house soils, the depth of topsoil was 16.2 cm. For the topsoils, hardness was 9.0 mm, bulk density was 1.09 Mg $m^{-3}$, and organic matter content was 29.0 g $kg^{-1}$. For the subsoils, hardness was 19.8 mm, bulk density was 1.32 Mg $m^{-3}$, and organic matter content was 29.5 g $kg^{-1}$; In upland soils, depth of topsoil was 13.3 cm. For the topsoils, hardness was 11.3 mm, bulk density was 1.33 Mg $m^{-3}$, and organic matter content was 20.6 g $kg^{-1}$. For the subsoils, hardness was 18.8 mm, bulk density was 1.52 Mg $m^{-3}$, and organic matter content was 13.0 g $kg^{-1}$. Classified by the types of crop, soil physical properties were high value in a group of deep-rooted vegetables and a group of short-rooted vegetables soil, but low value in a group of leafy vegetables soil; In orchard soils, the depth of topsoil was 15.4 cm. For the topsoils, hardness was 16.1 mm, bulk density was 1.25 Mg $m^{-3}$, and organic matter content was 28.5 g $kg^{-1}$. For the subsoils, hardness was 19.8 mm, bulk density was 1.41 Mg $m^{-3}$, and organic matter content was 15.9 g $kg^{-1}$; In paddy soils, the depth of topsoil was 17.5 cm. For the topsoils, hardness was 15.3 mm, bulk density was 1.22 Mg $m^{-3}$, and organic matter content was 23.5 g $kg^{-1}$. For the subsoils, hardness was 20.3 mm, bulk density was 1.47 Mg $m^{-3}$, and organic matter content was 17.5 g $kg^{-1}$. The average of bulk density was plastic film house soils < paddy soils < orchard soils < upland soils in order, according to land use. The bulk density value of topsoils is mainly distributed in 1.0~1.25 Mg $m^{-3}$. The bulk density value of subsoils is mostly distributed in more than 1.50, 1.35~1.50, and 1.0~1.50 Mg $m^{-3}$ for upland and paddy soils, orchard soils, and plastic film house soils, respectively. Classified by soil textural family, there was lower bulk density in clayey soil, and higher bulk density in fine silty and sandy soil. Soil physical properties and distribution of topography were different classified by the types of land use and growing crops. Therefore, we need to consider the types of land use and crop for appropriate soil management.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.220-230
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• 1992

Soil temperature is one of the important environmental factors which control all the physical, chemical and biological processes in soil including germination and root growth of plants and other organisms living in the soil ecosystem. Soil water and nutrient availability and mobility are temperature dependent. Soil temperature change is depended primarily upon energy exchange in soil surface, meteorological variance and physical properties of the soils which are closely related to heat transfer mechanism. In this study physical properties including bulk density, soil texture and organic matter content were measured and thermal diffusivity on the soils was calculated. Soil samples from the 66 meteorological stations under the Korea Meteorology were collected and the physical parameters were measured. To obtain relationship between thermal diffusivity and soil water content a heat probe thermal diffusivity measurement apparatus was designed and used in this experiment. According to the survey on soil physicsal properties on the 66 meteorological stations, the 52% of the surface soil texture were sandy loam and laomy sand or sand, 38% were loam and silty loam, and 10% were clay loam and silty clay loam. The bulk density which was closely related with thermal properties showed average of $1.41g/cm^3$ for sandy soils, $1.33g/cm^3$ for loam and silty loam soils, and $1.21g/cm^3$ for clay loam and silty clay loam soils. The apparent thermal diffusivity of the upper layer from 0 to 30cm ranged from 1.16 to $8.40{\times}10^{-3}cm^3/sec$ with average of $3.53{\times}10^{-3}cm^3/sec$. The apparent thermal diffusivities of the Jeju soils of which organic matter contents were high and the bulk densities were low were near $2{\times}10^{-3}cm^3/sec$. The thermal diffusivity of snow measured in Chuncheon ranged from 0.822 to $2.237{\times}10^{-3}cm^3/sec$. The damping depth calculated from the thermal diffusivity ranged from 5.92 to 13.65cm for daily basis and 124 to 342cm for yearly basis. The significant regression equation to estimate thermal diffusivity with bulk density and soil water content was obtained by the heat probe in laboratory.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.3
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• pp.155-159
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• 1993

This study was initiated to obtain the scientific information for the improvement of paddy soil. Mean values and mutual relationships of bulk density, pH values and the content of organic matter were investigated at the 124 field sites shown to be nationwide high-yielding, young seedling field s and their neighboring fields under the different soil textures and depths. The soil samples were collected and those samples were analyzed in the laboratory of Agricultural Sciences Institute. Mean values among the different soil textures and depths were estimated with loam-textured. Bulk density were significantly correlated with sand and silt in topsoil, and that were appeared to be correlated to sand, silt + clay, pH and content of organic matter highly significant in 1% level. Regression equation of soil bulk density(Y) to clay(C), orgnic matter (OM) and content of silt + clay(S+C) were as follows for the topsoil, Y=1.365+0.006C-0.003(S+C)~0.034OM (R=0.067*), and for the subsoil, Y=1.548 -0.002C-0.0007 (S+C) -0.036OM (R=0.122**).

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1548-1552
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• 2007

최근 유역단위의 수자원 계획 및 관리를 비롯하여 물 배분 문제 등에 관심이 집중되면서 장기유출모의 또한 국내에 많이 적용되고 있는 실정이다. 장기유출 모의시 가장 중요시 되는 부분 중 하나는 정확한 토양 수분 모의이며 이는 다양한 토양특성인자와 매우 밀접한 관계가 있을 뿐 아니라 지표면 유출량, 중간 유출량, 지하수 유출량 및 증발산량에도 큰 영향을 주게 된다. 통상 토양수분 함양량을 비롯하여 수문성분 발생량에 영향을 주는 대표적인 토양 매개변수는 토양의 깊이, 용적밀도, 포화수리전도도, 가용토양수분량, 포장용수량, 영구위조점 등이 있다. 본 연구에서는 이러한 토양 특성인자의 변화에 따른 수문성분의 변동성을 정량적으로 평가하기 위해 토양 매개변수들을 물리적으로 고려할 수 있으며 최근 국내에 많이 활용되고 있는 SWAT 모형을 이용하여 토양 매개변수 변화에 따른 수문성분 변화량을 분석하고자 한다.