• Title/Summary/Keyword: Soil condition

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Effect of Soil Water Stress on Yield and Quality of Korean Wheat

  • Han-yong Jeong;Yulim Kim;Chuloh Cho;Jinhee Park;Chon-Sik Kang;Jong-Min Ko;Jiyoung Shon
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2022.10a
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    • pp.62-62
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    • 2022
  • Among annual precipitation in Korea (1306.3 mm), 54% of it falls intensively in summer, and only about 12.4% falls in April and May, when the water requirement of wheat is the highest. Korean wheat also could be damaged by soil water excess stress as frozen soil thaws after winter (late Feb-Mar). This study was conducted to evaluate effect of soil water stress on yield and quality of Korean wheat cultivar 'Saegeumgang'. Soil water treatments consisted of 4 treatments; water excess treatment in tilling stage (3.23-3.30), drought treatment in ripening stage (Apr-Jun), irrigation treatment in ripening stage (5.10) and standard condition. There was no significant difference between the treatment conditions for culm length, and the number of spike number was the highest in the order of irrigation in the ripening period (951)> standard cultivation (876)> excess water treatment in the tilling stage (752)> drought treatment in the ripening stage (767/m2). Test weight and Thousand grain weight were 548g/L and 22. lg respectively, which were lower than other treatments, and there was no significant difference between the other treatments. Abortive grain was 5.4kg/10a which was lower than other treatment, and there was no significant difference between the other treatment than other treatments. In drought treatment, protein content was 11.9% which is the highest among all treatments, and SDS-sedimentation value was 27.2ml under drought treatment which was very low compared to other treatments. Therefore, wheat yield and spike number were decreased in excess water condition at tilling stage and drought condition at ripening stage. Furthermore, wheat quality became deteriorate in drought condition at ripening stage.

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Comparison of Infiltration Rate of Slope in Model Test and Finite Element Analysis (모형시험과 유한요소해석에서 비탈면 강우의 침투량 비교)

  • Yu, Yong-Jae;Kim, Jae-Hong
    • Land and Housing Review
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    • v.9 no.2
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    • pp.51-57
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    • 2018
  • The causes of landslides are dependant on rainfall events and the soil characteristics of a slope. For the conventional slope stability, the slope stability analysis has been carried out assuming the saturated soil theory. But, in order to clearly explain a proper soil slope condition by rainfall, the research should be performed using the unsaturated soil mechanism suitable for a soil slope in the field. In the study, by using two major categories of soils in Korea, such as granite and gneiss weathered soils, landslide model test and finite element method have been compared with the difference of seepage and soil stability analysis. The hydraulic conductivity of gneiss weathered soil is slower than that of granite weathered soil, and the gneiss weathered soil contains much finer soils than the granite weathered soil. It was confirmed that the instability of the slope was progressing slowly due to the slow rate of volumetric water content of the surface layer.

A new way to design and construct a laminar box for studying structure-foundation-soil interaction

  • Qin, X.;Cheung, W.M.;Chouw, N.
    • Earthquakes and Structures
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    • v.17 no.5
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    • pp.521-532
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    • 2019
  • This paper describes the construction of a laminar box for simulating the earthquake response of soil and structures. The confinement of soil in the transverse direction does not rely on the laminar frame but is instead achieved by two acrylic glass walls. These walls allow the behaviour of soil during an earthquake to be directly observed in future study. The laminar box was used to study the response of soil with structure-footing-soil interaction (SFSI). A single degree-of-freedom (SDOF) structure and a rigid structure, both free standing on the soil, were utilised. The total mass and footing size of the SDOF and rigid structures were the same. The results show that SFSI considering the SDOF structure can affect the soil surface movements and acceleration of the soil at different depths. The acceleration developed at the footing of the SDOF structure is also different from the surface acceleration of free-field soil.

탈질 조건에서 투과매질 내 미생물 성장에 관한 연구

  • 최영화;오재일;배범한
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2002.09a
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    • pp.366-369
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    • 2002
  • Subsurface biobarrier technology has potential applications to contain contaminated groundwater and/or to degrade toxic pollutants in groundwater. Most biobarrier studies were conducted under aerobic condition, however there were several obstacles to make aerobic condition. Thus, In this study, we examined biobarrier formation under denitrifying condition by using nitrate as an electron acceptor. Experiments were performed with a sand column inoculated with activated sludge from the nearby WWTP. The substrate medium was pumped to the sand column in an upflow mode. During the low substrate loading rate period, the extent of reduction rate in hydraulic conductivity was found similar throughout the column, and permeability became relatively stable after couple of days. However, during the high substrate loading rate period, the column demonstrated a gradient of permeability reduction, with the greatest reduction in sections nearest the column inlet. Rapid growth of microorganisms near the column inlet resulted in the unbalanced reduction of hydraulic conductivity throughout the sand column. As a result, at this denitrifying condition the thickness of biobarrier could be controlled by adjusting the medium conditions of microbial growth.

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불포화 사질토 지반의 지반조건 및 침출수 오염도에 따른 전기비저항의 변화

  • 오명학;이주형;박준범;김형석
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2001.09a
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    • pp.47-50
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    • 2001
  • The laboratory tests were peformed to investigate the relationship between electrical resistivity and the unsaturated subsurface condition and to evaluate the contamination due to leachate based on measuring electrical resistivity. For weathered granite soil, the electrical resistivity of soil decreases as moisture density increases. The electrical resistivity of soil decreases as the concentration of leachate in pore fluid increases since leachate contains various ionic constituents. And the modified Archie's equation for applying to unsaturated sand is derived by regression analysis.

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Degradation of the Herbicide, Alachlor, by Soil Microorganisms -III. Degradation under an Upland Soil Condition- (제초제 Alachlor의 토양미생물에 의한 분해 -제 3 보. 밭토양 조건에서의 분해-)

  • Lee, Jae-Koo
    • Applied Biological Chemistry
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    • v.29 no.2
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    • pp.182-189
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    • 1986
  • Alachlor, 2-chloro-2',6'-diethyl-N-(methoxymethyl) acetanilide produced four major degradation products, when incubated under an upland soil condition for 80 days. They include 8-ethyl-2-hydroxy-N-(methoxymethyl)-1,2,3,4-tetrahydroquinoline (m/z 221), N-hydroxyacetyl-2,3-dihydro-7-ethylindole (m/z 205), 2-hydroxy-2',6'-diethyl-N-(methoxymethyl) acetanilide (m/z 251), and 9-ethyl-1,5-dihydrol-(methoxymethyl)-5-methyl-4,1-benzoxazepin-2 (3H)-one (m/z 249). The products turned out to be a little different from those obtained under the flooded paddy soil condition used in the previous paper. The plausible pathways for the degradation were proposed.

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Reduction of Hydraulic Conductivity by Soil Injection of Bacteria (Bacteria 토양주입을 통한 투수계수 감소)

  • 송영우;김건하;구동영
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.03b
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    • pp.331-337
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    • 2000
  • When microorganism is injected into porous medium such as soils, biomass retained in the pore. Bacteria within these microcolonies produced large amounts of exopolysaccharides and formed a plugging biofilm. Soil pore size and shape are varied from the initial condition as a result of biofilm formation, which make hydraulic conductivity reduced and friction rate between soil aggregates increased. In this research, hydraulic conductivity reduction was measured after microorganism are inoculated and cultured with synthetic substrate and nutrient. Also, pore sand of before and after biofilm formation compared with scanning electron microscopy. Hydraulic conductivity of Sand and Poorly Graded Sand was decreased approximately 1/10∼1/100 after biomass inoculation and cultivation. Biofilm attached on soil aggregates is resistant to acidic or basic condition.

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Effects of Seabed Soil Parameters on Wave Dispersion Relationship (해저지반의 지반상수가 분산관계식에 미치는 영향)

  • Yang, Soonbo;Kim, Namhyeong;Ko, Yongsu
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2014.06a
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    • pp.258-259
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    • 2014
  • It is needed the introduction of a new wave dispersion relationship considering the condition of seabed to examine closely the interaction between wave and seabed. In this study, a wave dispersion relationship is newly developed considering the condition of seabed such as permeability and displacement. Wave damping rates are compared and analysed according to the various soil parameters such as seabed soil thickness, elastic modulus, saturation, permeability, and porosity.

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Assessement of Consolidation Characteristics by Field Instrumentation (현장계측사례를 통한 압밀특성 평가)

  • Song, Jeong-Rak;Baek, Seung-Hun;O, Da-Yeong
    • Proceedings of the Korean Geotechical Society Conference
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    • 1992.10a
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    • pp.121-130
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    • 1992
  • Assessement of comsolidation characteristics of soft soil is very important in the project of soft soil improvement. In the design step, the consolidation characteristics of soil is determined by the laboratory tests (typically oedometer test), generally. But there is big differences between the condition of laboratory test and the condition of field(in situ). the differences results in the considerable difference between the predicted and measured consolidation behavior. This article analyzed the consolidation data of the "SOFT SOIL IMPROVEMENT PROJECT of the 2nd Namdong Industrial Complex at Inchon". The project was improving the road way net work in the 2nd Namdong Industrial Complex by preloading and sand pile method. Field instrumentation was performed at 10 points which consist of pneumatic piezometers, magnetic probe extensometers, inclinometers and electronic dipmeter. The results showed that there is big difference in the laboratory predicted consolidation behavior and field consolidadion behavior. Also there was big difference in the settlement behavior and pore pressure behavior. This article investigated the above factors by comparing the settlement, pore pressure and strength at different conditions.onditions.

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Remediation of Insecticides (Parathion, Diazinon) Contaminated Soil by Washing Process (토양 세척을 통한 살충제 (파라티온, 다이아지논)로 오염된 토양의 정화)

  • 현재혁;백정선;조미영
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 1999.10a
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    • pp.3-6
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    • 1999
  • Several chemical washing procedures were applied to Parathion and Diazinon contaminated soil. Batch and column tests were performed to determine the insecticides extraction efficiency as a function of pH. Washing efficiency of methanol is more higher than that of water and HCl when washed parathion and diazinon are. Those are completely miscible with most organic solvents. For parathion, release trend is increased as pH is increased because it is hydrolyzed easily at the condition of alkali. But diazinon shows reverse because diazinon is decomposed rapidly at the condition of acidic So, diazinon is more released than parathion is because this experiment is peformed in acidic and weak acidic conditions. Generally, parathion and diazinon are classified as having low mobility, so they can be easily controlled if the proper washing process are applied.

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