• Journal of Ecology and Environment
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• 제30권2호
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• pp.151-159
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• 2007

We studied the optimal ranges of water and soil characteristics for wetland plants, particularly Scirpus tabernaemontani (softstem bulrush) and Typha latifolia (broadleaf cattail), which are dominant species with potential for restoration of Korean wetlands. We observed vegetation in S. tabernaemontani and T. latifolia communities from the mid to late June, 2005, and measured characteristics of water environments such as water depth (WD), temperature (WT), conductivity (WC), and concentration of several ions $(NO_3{^-}-N,\;Ca^{2+},\;Na^+,\;Mg^{2+},\;and\;K^+)$, and characteristics of soil environments such as soil texture, organic matter (loss on ignition, LOI), conductivity, and pH. The S. tabernaemontani community was accompanied by Zizania latifolia (Manchurian wildrice), Persicaria thunbergii (Korean persicary), Actinostemma lobatum (lobed actinostemma), and Beckmannia syzigachne (American slough grass), while the T. latifolia community was accompanied by P. thunbergii, T. angustifolia (narrowleaf cattail), and Glycine soja (wild soybean). We defined the optimal range for distribution (ORD) as the range that each plant was crowded. The optimal range of water characteristics for the S. tabernaemontani community was a $WD\;10{\sim}50cm,\;WT\;24.0{\sim}32.0^{\circ}C,\;WC\;100{\sim}500{\mu}S/cm,\;{NO_3}{^-}-N\;0{\sim}60ppb,\;K^+\;0.00{\sim}1.50ppm,\;Ca^{2+}\;7.50{\sim}17.50ppm,\; Na^+\;2.50{\sim}12.50ppm,\;and\;Mg^{2+}\;3.00{\sim}7.00ppm$. In addition, the optimal range of soil characteristics for the S. tabernaemontani community was a soil texture of loam, silty loam, and loamy sand, $LOI\;8.0{\sim}16.0%,\;pH\;5.25{\sim}6.25$, and conductivity $10{\sim}70{\mu}S/cm$. The optimal range of water characteristics for the T. latifolia community was a $WD\;10{\sim}30cm,\;WT\;22.5{\sim}27.5^{\circ}C,\;WC\;100{\sim}400{\mu}S/cm,\;{NO_3}{^-}-N\;0{\sim}60ppb,\;K^+\;0.00{\sim}1.50ppm,\;Ca^{2+}\;0.00{\sim}17.50ppm,\;Na^+\;0.00{\sim}12.50ppm,\;and\;Mg^{2+}\;0.00{\sim}5.00ppm$, and the optimal range of soil characteristics for the T. fatifolia community was a soil texture of loam, sandy loam, and silty loam, LOI $3.0{\sim}9.0%,\;pH\;5.25{\sim}7.25$, and conductivity $0{\sim}70{\mu}S/cm$.

• 한국CDE학회논문집
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• 제20권3호
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• pp.230-237
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• 2015

Soil deformation on the off-load ground is significantly affected by soil conditions, such as soil type, water content, and etc. Thus, the soil characteristics should be estimated for predicting vehicle movements on the off-load conditions. The plate-sinkage test, a widely-used experimental test for predicting the wheel-soil interaction, provides the soil characteristic parameters from the relationship between soil stress and plate sinkage. In this study, soil stress under the plate-sinkage situation is calculated by the DEM (Discrete Element Method) model. We developed a virtual soil bin with DEM to obtain the vertical reaction forces under the plate pressing the soil surface. Also parametric studies to investigate effects of DEM model parameters, such as, particle density, Young's modulus, dynamic friction, rolling friction, and adhesion, on the characteristic soil parameters were performed.

• 지질공학
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• 제17권2호
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• pp.205-215
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• 2007

이 연구는 산사태가 발생한 자연사면의 토층을 대상으로 여러 토질시험을 실시하여 산사태에 영향을 미치는 토질특성을 고찰하고, 산사태와의 관련성 및 각 물성간의 상관관계를 분석하였다. 연구지역은 지질조건이 다른 3개지역으로서 같은 시기에 집중호우로 인해 산사태들이 집중적으로 발생된 경기 장흥 편마암류지역, 경북 상주 화강암류지역 및 경북 포항 제3기퇴적암류지역이다. 지질별로 다소의 차이는 있으나 산사태발생지역의 토충은 미발생지역에 비해 세립자의 함유 비율이 더 높고 대체로 큰 간극율과 작은 밀도특성을 갖는다. 그리고 동일한 지질조건인 경우 투수성이 양호한 토층이 산사태에 더 취약한데, 투수성은 입도분포, 간극크기, 흙입자의 거칠기 및 구조 등의 토질특성과 풍화나 퇴적환경 등 지질성인에 영향을 받는다. 모든 지질조건에서 전단저항각이 큰 토층은 작은 토층에 비해 산사태에 더 안정한 지반으로 분류된다. 투수계수에 영향을 미치는 토질인자는 유효경, 균등계수, 곡률계수, 간극율 및 밀도 등이고 이들은 서로 상관관계에 있는 물성이다. 이러한 상관성은 3개지역 모두에서 유사한 경향성을 보였다. 한편, 간극비와 간극율이 크면 투수계수도 따라서 커지는 상호 비례적 관계를 갖는다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권6호
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• pp.119-128
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• 2012

The applicability and accuracy of Revised Universal Soil Loss Equation (RUSLE) model on the estimation of soil loss at impacted area of shooting range was tested to further the understanding of soil erosion at shooting ranges by using RUSLE. At a shooting range located in northern Kyunggi, the amount of soil loss was estimated by RUSLE model and compared with that estimated by Global Positioning System-Total Station survey. As results, the annual soil loss at a study site (202 m long by 79 m wide) was estimated to be 2,915 ton/ha/year by RUSLE and 3,058 ton/ha/year by GPS-TS survey, respectively. The error between two different estimations was less than 5%, however, information on site conditions should be collected more to adjust model coefficients accurately. At the study shooting range, sediments generated by rainfall was transported from the top to near the bottom of the sloping face through sheet erosion as well as rill erosion, forming a gully along the direction of the storm water flow. Coarser fractions of the sediments were redeposited in the limited area along the channel. Distribution characteristics of explosive compounds in soil before and after summer monsoon rainfall in the study area were compared with the erosion patterns. Soil sampling and analyses results showed that the dispersion of explosive compounds in surface soil was consistent with the characteristics of soil erosion and redeposition pattern of sediment movements after rainfalls.

• 한국농공학회지
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• 제34권4호
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• pp.69-79
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• 1992

To estimate soil behavior and structural characteristics under the conditions of cyclic loading, freezing & thawing and initial state, several testing was performed and obtained following results. 1.After repeated freezing and thawing processes, original soil structure was destroyed and changed to globular structure from honeycomb or tube in its structure types. Also above processes resulted increasing the soil compression strain while decreasing the failure stress in stress-strain relationship and reached the soil structure into the mode of brittle fracture. Under cyclic loading conditions, soil cluster which was originally dispersed structure colloided with each other, seperated, and finally the soil failed due to the effect of overcompaction. 2.Through the stabilization processes seperated by four steps, the structure of soil skeleton was changed to quite different globular type. The degree of compressibility of soil was decreased in the normally consolidated zone, while the strength against external load increased due to soil particle stabilization. 3.Soil stress-strain chracteristics were largely influenced by repeated up and down processes of temperature. The maximum deformation was obtained in the case of temperature between 0 10˚C by the reseon of particle cluster reformation. 4.Soil compressibility was largely influenced by the optimum moisture content. Under freezing process, swelling could be found and its magnitude was proportional to the density of soil. 5.Density of soil was decreased as increasing the number or repeated freezing and thawing processes and the largest decreasing rate was found at the first turning point from freezing to thawing cycle.

• 한국농공학회지
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• 제34권4호
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• pp.48-58
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• 1992

This study was conducted to investigate the consolidation characteristics of the marine clay, treated with predetermined ratios of lime and briquette ash. The standard consolidation test was performed for the sample of mixture remoulded under the condition of optimum moisture content. The results obtained were as follows ; 1.The increase of the consolidation coefficient due to load increament was larger in the lime treated soil and briquette ash treated soil than in the untreated soil. The decrease of the compression index due to admixing ratio of additives was smaller in the former than in the latter. 2.The increase of the secondary consolidation coefficient of the untreated soil due to load increment was minimal, while that of lime treated soil and the lime-briquette ash treated soil was conspicuous and that of briquette ash treated soil was slight. 3.The $C\alpha$/Cc relationship of untreated soil was represented by colsely distributed points. That of briquette ash treated soil, lime treated soil and the lime-briquette ash treated soil was represented by linear distribution. The $C\alpha$/Cc values of untreated soil, briquette ash treated soil and lime treated soil were approximately 0.049, 0.044 and 0.031, respectively. 4.The maximum consolidation coefficient was obtained with lime and briquette ash (lime : briquette .h 2 :1) mixture ratio of 15%. And the minimum secondary consolidation coefficient, compression index was obtained with same mixture ratio. The required quantity of lime could be reduced and the consolidation was accelerated by applying the above mixture ratio.

• 한국토양비료학회지
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• 제48권3호
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• pp.189-193
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• 2015

Bad drainage problems from paddy fields adjacent to roads are caused by higher constructed roads which change topography of paddy fields to concave topography and artificial pan to prevent road erosion when road constructions are occurred. This study investigated effects of topography changes on soils by road constructions. Soil samples were investigated by physico-chemical analyses and micromorphology analyses from representative soil profile of Sachon series and soil samples. The characteristics of Sachon series that were adjacent to roads were fewer redoximorphic features (RMF) and increase in grey layers than the original Sachon series. The characteristics of Yecheon Series were shown from Jeollanamdo - Suncheon > Chungchungnamdo - Cheonan > Gangwondo - Wonju. Mosaic speckles were shown from micromorphological analyses because of repeat of shrink and expansion by wetting and drying. The location of graying in soil clods were found from coarse stone blocks to fine stone blocks and color changes of composed particles were also found.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권1호
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• pp.7-18
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• 2015

The characteristics of As and heavy metals depend on the oxidation/reduction condition of the soil environment. The most heavy metals are immobilized by the reduction condition whereas As, Fe and Mn become more soluble. Therefore this study estimated the stabilization efficiency of the agricultural paddy soil in the vicinity of the abandoned mine using a flooded column test including analysis of the soil solution, contaminants fractionation and rice grain. Limestone and steelmaking slag were used as amendments for stabilization of the contaminated soil. In an analysis of the soil solution, the mobile characteristics of Fe and Mn, which were used as electron acceptors of the microorganisms, were controlled by increasing the pH by adding alkali amendments. This means that the contaminants combined with Fe and Mn can be stable under flooded reduction condition. However, the concentrations of cationic heavy metals (Cd, Pb, and Zn) were also decreased without amendments because the carbonates produced from microbial respiration increased the pH of the soil solution. In the amended soil, the specific sorbed fraction of As and carbonates fraction of heavy metals were increased when compared to the control soil at the end of the column test. Especially in heavy metals, the increase of carbonates fraction seems to be influenced by alkali amendments rather than microbial respiration. Because of the stabilization effect in the flooded paddy soil, the contents of As and Zn in rice grain from amended soil were lower than that of the control soil. But additional research is needed because of the relatively higher Pb content identified in the rice grain from the amended.

• 한국환경농학회:학술대회논문집
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• 한국환경농학회 2011년도 30주년 정기총회 및 국제심포지엄
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• pp.3-20
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• 2011

토양은 직 간접적으로 인간의 삶과 질에 영향을 미치게 된다. 일반적으로 비옥한 토양을 가진 지역은 척박한 지역에 비해 상대적으로 풍요한 삶을 누리게 되며 풍습, 관습, 문화 등이 달라진다. 제주지역은 육지부와 기후가 다르지만 토양은 더욱 다르다. 특히 좁은 제주도 내에서도 지역마다 자연비옥도와 토지생산성이 달라서 화학비료가 없었던 과거에는 토양의 성질이 마을의 형성, 풍습, 제사습관 등에 직접적으로 영향을 미쳤을 것으로 보고 있다. 제주해역은 대만에서부터 폭 60km의 구로시오(黑潮) 해류가 3노트의 속도로 흐르다가 나뉘어 지는 기점이다. 이 해류는 옛사람들이 육지에서 제주로 해류를 거슬러 오는 것을 매우 힘들게 하였으며, 제주만의 독자적인 문화와 풍습을 낳게 하는 원인이 되었다. 제주에서 고고학, 민속학을 연구하는 인문 사회학자들이 갖고 있는 의문은 동서 73km, 남부 31km, 면적 $1,825\;km^2$의 작은 섬에서 고인돌과 유적이 발견되는 지역이 한정되어 있고, 지역마다 풍습과 민요가 다르다는 것이다. 심지어 1 km 이내의 짧은 거리의 마을도 다른 것이 매우 많다. 필자는 우연히 '90년대 말 인문 사회학자와 유적, 풍습 등을 조사하는 과정에서 제주를 설명하는 데 토양학적인 접근이 인문 사회분야의 여러 가지 의문점을 풀어내는데 중요한 실마리를 제공하고 있다는 것을 알았다. 그 내용의 일부를 강의에 이용하였으며, 원고 작성방식도 인문학 방식을 많이 따랐다.

• 한국토양비료학회지
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• 제17권2호
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• pp.141-146
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• 1984

제주도(濟州道) 토양(土壤)의 약(約)93%에 해당(該當)하는 흑색토(黑色土), 농암갈색토(濃暗褐色土), 암갈색토(暗褐色土) 및 갈색토(褐色土)의 토양단면내(土壤斷面內) 변이성(變異性) 및 순수성(純粹性)을 분석(分析)하고 토색별(土色別) 토양특성(土壤特性)에 대한 특정(特定) 신뢰구간(信賴區間)에서 주어진 정도내(精度內)에 요구(要求)되는 표본(標本)크기를 결정(決定)하고자 수행(遂行)한 결과(結果)는 마음과 같다. 1. 대체(大體)로 토양화학성(土壤化學性)은 물리성(物理性)보다 변이성(變異性)이 컸으며 토심별(土深別)로는 심토(心土)가 표토(表土)보다 컸다. 2. 갈색토(褐色土)의 변이계수(變異係數)는 토양특성(土壤特性)에 관계(關係)없이 가장 낮았다. 3. 토양통(土壤統) 설정시(設定時) 순수성(純粹性)은 갈색토(褐色土) 74.1, 암갈색토(暗褐色土) 60.8, 흑색토(黑色土) 55. 6, 그리고 농암갈색토(濃暗褐色土) 46.9% 이었다. 4. 토양특성(土壤特性)을 유의수준(有意水準) 0.00에서 모평균(母平均)의 10% 정도(精度)로 추정(推定)하는데 요구(要求)되는 표본標本)크기를 결정(決定)하였다.