• 한국토양비료학회지
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• 제44권6호
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• pp.1286-1294
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• 2011

This paper reviews the future directions and perspectives on the soil environmental researches in the 21 century. Previously, the principal emphasis of soil environmental researches had put on the enhancement of food and fiber productions. Beside the basic function of soil, however, the societal needs on soil resources in the 21st century have demands for several environmental and social challenges, occurring regionally or globally. Typical global issues with which soil science should deal include food security with increasing agronomic production to meet the exploding world population growth, adaptation and mitigation of climate change, increase of the carbon sequestration, supply of the biomass and bioenergy, securing the water resource and quality, protection of environmental pollution, enhancing the biodiversity and ecosystem health, and developing the sustainable farming/cropping system that improve the use efficiency of water and agricultural resources. These challenges can be solved through the sustainable crop production intensification (SCPI) or plant welfare concept in which soil plays a key role in solving the abovementioned global issues. Through implementation of either concept, soil science can fulfill the goal of the modern agriculture which is the sustainable production of crops while maintaining or enhancing the ecosystem function, quality and health. Therefore, directions of the future soil environmental researches should lie on valuing soil as an ecosystem services, translating research across both temporal and spatial scales, sharing and using data already available for other purposes, incorporating existing and new technologies from other disciplines, collaborating across discipline, and translating soil research into information for stakeholders and end users. Through the outcomes of these approaches, soil can enhance the productivity from the same confined land, increase profitability, conserve natural resource, reduce the negative impact on environment, enhance human nutrition and health, and enhance natural capital and the flow of ecosystem services. Soil is the central dogma, final frontier and new engine for the era of sustainability development in the $21^{st}$ century and thus soil environmental researches should be carried according to this main theme.

• Earthquakes and Structures
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• 제27권1호
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• pp.1-15
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• 2024

In order to enhance the seismic performance of base-isolated structures on soft foundations, the hybrid system of base-isolated system (BIS) and shape memory alloy inerter (SMAI), referred to as BIS+SMAI, is for the first time here proposed. Considering the nonlinear hysteretic relationships of both the isolation layer and SMA, and soil-structure interaction (SSI), the equivalent linearized state space equation is established of the structure-BIS+SMAI system. The displacement variance based on the H₂ norm is then formulated for the structure with BIS+SMAI. Employing the particle swarm optimization, the optimization design methodology of BIS+SMAI is presented in the frequency domain. The evolvement rules of BIS+SMAI in the effectiveness, robustness, SMA driving force, inertia force, stroke, and damping enhancement effect are revealed in the frequency domain through changing the inerter-mass ratio, structural height, aspect ratio, and relative stiffness ratio between the soil and structure. Meanwhile, the validation of BIS+SMAI is conducted using real earthquake records. Results demonstrate that BIS+SMAI can effectively reduce the isolation layer displacement. The inerter can significantly increase the hysteretic displacement of SMA and thus enhance its energy dissipation capacity, implying that BIS+SMAI has better effectiveness than BIS+SMA. Although BIS+SMAI and BIS+ tuned inerter damper (TID) have practically the same effectiveness, BIS+SMAI has the lower optimum damping, significantly smaller inertia force, and higher robustness to perturbations of the optimum parameters. Therefore, BIS+SMAI can be used as a more engineering realizable hybrid system for enhancing the performance of base-isolated structures in soft soil areas.

• The Plant Pathology Journal
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• 제22권4호
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• pp.364-368
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• 2006

Survival of biocontrol agents and their effective colonization of rhizhosphere are the essential components for successful disease suppression. The effects of hydrogel supplement on bacterial survival and disease control were evaluated in pot and in the field. Addition of 2% hydrogel material to potting soil resulted in significant enhancement of colonization of biocontrol agent Serratia plymuthica A21-4 both in soil and rhizosphere of pepper plants. Rhizosphere colonization of S. plymuthica A21-4 retrieved from 40 days old pepper seedlings indicated 100 times higher bacterial population in hydrogel treated soil than in ordinary pot soil. The pepper plants sown in hydrogelated potting soil showed higher seed germination rate and the better growth of pepper plant than those in ordinary commercial pot soil. Although the suppression of Phytophthora capsid density in the potting soil by treatment of biocontrol agent A21-4 was not significantly different between in hydrogelated soil and ordinary potting soil, the suppression of Phytophthora blight between two treatments was significantly different. A21-4 treatment in hydrogelated potting soil was completely disease-free while same treatment in ordinary potting soil revealed 36% disease incidence. Our field study under natural disease occurrence also showed significantly less disease incidence(12.3%) in the A21-4 treatment in the hydrogelated soil compared to other treatments. Yield promotion of pepper by the A21-4 treatment in the hydrogelated potting soil was also recognized. Our results indicated that hydrogel amendment with biocontrol agent in pot soil would be a good alternative to protect pepper seedlings and increase plant yield.

• 한국토양비료학회지
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• 제45권6호
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• pp.1237-1241
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• 2012

Heavy metal pollution in agricultural field has been a critical issue in worldwide. For this reason, remediation technologies for heavy metal polluted soil are applied especially near at the abandoned metal mine. Soil quality analysis is also an important factor for proper management in heavy metal polluted agricultural field. In this study, scoring function was utilized to evaluate soil quality in heavy metal polluted agricultural field. Among other soil properties, bulk density, soil pH, EC, $NH_4$-N, $NO_3$-N, and cation exchange capacity (CEC) were determined for minimum data set (MDS) with principal component analysis. Result showed that both upland and paddy soil contaminated with heavy metal were not suitable for crop growth except scoring of soil pH for paddy soil and CEC for upland soil. This result might indicate that chemical stabilization technology with chemical amendment could be adapted for remediation method for heavy metal polluted agiclutural field not only for heavy metal immobilization but also enhancement of soil condition for crop growth.

• Journal of Microbiology and Biotechnology
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• 제11권4호
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• pp.607-613
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• 2001

The biodegradation rates of diesel oil by a selected diesel-degrading bacterium, Pseudomonas stutzeri strain Y2G1, and microbial consortia composed of combinations of 5 selected diesel-degrading bacterial were determined in liquid and soil systems. The diesel degradation rate by strain Y2G1 linearly increased $(R^2=0.98)$ as the diesel concentration increased up to 12%, and a degradation rate as high as 5.64 g/l/day was obtained. The diesel degradation by strain Y2G1 was significantly affected by several environmental factors, and the optimal conditions for pH, temperature, and moisture content were at pH8, $25^{\circ}C$, and 10%, respectively. In the batch soil microcosm tests, inoculation, especially in the form of a consortium, and the addition of nutrients both significantly enhanced the diesel degradation by a factor of 1.5 and 4, respectively. Aeration of the soil columns effectively accelerated the diesel degradation, and the initial degradation rate was obviously stimulated with the addition of inorganic nutrients. Based on these results, it was concluded that the major rate-limiting factors in the tested diesel-contaminated soil were the presence of inorganic nutrients, oxygen, and diesel-degrading microorganisms. To resolve these limiting parameters, bioremediation strategies were specifically designed for the tested soil, and the successful mitigation of the limiting parameters resulted in an enhancement of the bioremediation efficiency by a factor of 11.

• 한국토양비료학회지
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• 제13권1호
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• pp.7-11
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• 1980

질소비료(窒素肥料)의 시용량(施用量)에 따른 암모니아의 휘산량(揮散量)을 밝히기 위하여 토양 25g에 요소태질소(尿素態窒素)를 3.75mg, 7.5mg, 11.25mg 씩 가(加)하여 7 주간(週間) $35{\sim}40^{\circ}C$로 보온 처리한 결과(結果)는 다음과 같다. 요소(尿素)의 시용량(施用量)이 증가함에 따라 암모니아의 휘산량(揮散量)이 증가하였는데 그 증가는 암모니아의 생성증가에 따른 토양반응의 상승(上昇)과 밀접(密接)한 관계가 있다. 2. 석회(石灰)의 과용(過用)은 요소(尿素)의 가수분해(加水分解)와 토양질소의 유효화를 휘제(揮制)하여 암모니아의 휘산량(揮散量)을 줄였다. 이 경향(傾向)은 토양의 pH가 8.0 이상(以上)이 되면 더욱 심(甚)해졌다.

• Journal of Biosystems Engineering
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• 제25권3호
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• pp.213-220
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• 2000

Grafting of fruit-bearing vegetables has been widely used to increase the resistance to soil-borne diseases, to increase the tolerance to low temperature or to soil salinity, to increase the plant vigor, and to extend the duration of economic harvest time. After grafting, it is important to control the environment around grafted seedlings for the robust joining of a scion and rootstock. Usually the shading materials and plastic films are used to keep the high relative humidity and low light intensity in greenhouse or tunnel. It is quite difficult to optimally control the environment for healing and acclimation of grafted seedlings under natural light. So the farmers or growers rely on their experience for the production of grafted seedling with high quality. If artificial light is used as a lighting source for graft-taking of grafted seedlings, the light intensity and photoperiod can be easily controlled. The purpose of this study was to develop a prototype system for the graft-taking enhancement of grafted seedlings using artificial lighting and to investigate the effect of air current speed on the distribution of air temperature and relative humidity in a graft-taking enhancement system. A prototype graft-taking system was consisted by polyurethane panels, air-conditioning unit, system controller and lighting unit. Three band fluorescent lamps (FL20SEX-D/18, Kumho Electric, Inc.) were used as a lighting source. Anemometer (Climomaster 6521, KANOMAX), T-type thermocouples and humidity sensors (CHS-UPS, TDK) were used to measure the air current speed, air temperature and relative humidity in a graft-taking system. In this system, air flow acted as a driving force for the diffusion of heat and water vapor. Air current speed, air temperature and relative humidity controlled by a programmable logic controller (UP750, Yokogawa Electric Co) and an inverter (MOSCON-G3, SAMSUNG) had an even distribution. Distribution of air temperature and relative humidity in a graft-taking enhancement system was fairly affected by air current speed. Air current speed higher than 0.1m/s was required to obtain the even distribution of environmental factors in this system. At low air current speed of 0.1m/s, the evapotranspiration rate of grafted seedlings would be suppressed and thus graft-taking would be enhanced. This system could be used to investigate the effects of air temperature, relative humidity, air current speed and light intensity on the evaportranspiration rate of grafted seedlings.

• 한국토양비료학회지
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• 제46권5호
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• pp.399-407
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• 2013

Organic grape was generally produced in rainshield or plastic greenhouse culture while most of fruits were produced in open field. But little attention has been given to soil properties with different culture facilities in organic grape cultivation. This study was conducted to investigate soil physico-chemical properties of organic grapes farms with different culture facilities and soil management practices. Organic fertilizer was main resource to manage soil at organic grapes farms. Organic grapes farms were applied with total amount of organic fertilizer at one time, either at basal or additional fertilization, whereas conventional grapes farms applied with split fertilization. Bulk density and penetration resistance of soil were lower at both rainshield and green manure-applied plastic greenhouse cultures than those at clean plastic greenhouse culture. Especially, in plastic greenhouse, sod culture with natural weed after green manure application was more effective than general sod culture in improving physical properties of the rhizosphere. The contents of organic matter, available phosphate and exchangeable potassium tended to increase in the soils applied with green manure, and the difference of soil chemical properties were significant between rainshield and plastic greenhouse cultures. The optimum soil management was required in plastic greenhouse because pH, available phosphate and exchangeable cations reached over optimum range. Consequently, the ground cover management is the key factor to affect the chemical properties as well as soil physical properties extensively in plastic greenhouse. It is found that sod culture with natural weed after green manure application resulted in enhancement of utilization efficiency of nitrogen, phosphoric acid and potassium in soil in comparison with general sod culture.

• 한국지하수토양환경학회지:지하수토양환경
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• 제29권1호
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• pp.51-62
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• 2024

A study was performed to investigate the positive impacts of humic substances (HS) on the growth of green barley, a type of green manure plant. The study was conducted in a pot culture using two different types of reclaimed soils that had been treated by land farming (DDC) and thermal desorption (YJ) methods, respectively. The experimental conditions consisted of three treatments: plant only (P), plant plus 2% HS, and no plant (control). After 89 days of culture in a controlled growth chamber, the growth of spring barley and activity of seven soil enzymes were measured. The results indicated that the addition of HS had a substantial (p<0.10) positive effect on shoot biomass in both types of soil. Furthermore, the addition of HS notably (p<0.05) enhanced all seven soil enzyme activities in both soils. Both the aboveground and belowground parts of barley plants were returned to soil and aged for 10 weeks in the same growth chamber, which resulted in notable enhancement in soil health indicators. These improvements included an increase in organic matter, a drop in bulk density, and an increase in the activity of seven different soil enzymes. When lentil seeds were planted in the aged soils, the development of the seedlings was more vigorous than that in the control in both soils, although allelopathy of barley suppressed lentil germination in soil with pH 7.0 but not in soil with pH 8.5.

• 한국산학기술학회논문지
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• 제16권5호
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• pp.3596-3601
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• 2015

진동해머에 의해 시공되는 말뚝의 거동을 분석할 목적으로 개발된 기존의 프로그램을 개선하고자 하였다. 진동해머-말뚝-지반으로 구성되는 진동시스템의 기존 지배방정식에 지반저항의 댐핑효과와 클러치마찰력을 추가하였다. 또한, 개발된 해석기법의 하중전이곡선을 모사하는 수정 Ramberg-Osgood 모델의 매개변수를 재산정하여 해석기법을 개선하고자 하였다. 수정된 프로그램에 의한 해석결과를 현장시험결과와 비교해 볼 때 시간에 따른 말뚝의 변위 및 하중전이거동이 현장시험결과에 좀 더 유사하였다. 개발된 프로그램에 의한 말뚝 관입깊이별 관입속도를 상용 프로그램에 의한 결과 및 현장시험결과와 비교해 볼 때 상용프로그램보다 훨씬 더 현장시험결과에 가까웠다.