THE DETERMINATION OF IONIC DIFFUSION COEFFICIENTS IN FIELD SOILS. I. DIFFUSION COEFFICIENTS IN SIEVED SOILS IN RELATION TO WATER CONTENT AND BULK DENSITY

1981 ◽  
Vol 32 (2) ◽  
pp. 225-236 ◽  
Author(s):  
P. B. BARRACLOUGH ◽  
P. B. TINKER
Keyword(s):  
Water Content ◽  
Bulk Density ◽  
Diffusion Coefficients ◽  
Ionic Diffusion ◽  
Field Soils

scholarly journals Mediate relation between electrical and thermal conductivity of soil

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Hans Schwarz ◽  
David Bertermann
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Water Content ◽  
Bulk Density ◽  
Geophysical Methods ◽  
Heat Extraction ◽  
Geothermal Systems ◽  
Corrective Factor ◽  
Thermal Conductivity Model

Abstract Thermal conductivity is a key parameter for many soil applications, especially for dimensioning shallow and very shallow geothermal systems based on the possible heat extraction rate and for modelling heat transfer processes around high voltage underground cables. Due to the limited purview of direct thermal conductivity measurements, for an investigation of extensive areas, usually other geophysical methods like electrical resistivity tomography measurements are applied. To derive thermal conductivity of soil from geoelectrical measurements a relation between electrical and thermal conductivity is needed. Until now only few approaches worked on a direct correlation between both conductivities. Due to the difficulties of a direct relation, within this study a modular approach of a mediate correlation between electrical and thermal conductivity was investigated. Therefore, a direct relationship between a corrected electrical conductivity and water content as well as the standard and simple thermal conductivity model of Kersten (Bull of the Univ Minnesota 28:1–227, 1949) was used. To develop this concept soil types of sand, silt loam and clay were investigated where different saturation steps and pressure loads were applied. For each configuration electrical and thermal conductivity as well as water content and bulk density was determined. To refine the results of the calculated water content a corrective factor was applied. Furthermore, bulk density as an inlet parameter of the Kersten equation was also derived based on electrical conductivity. The suggested proceeding enables the determination of thermal conductivity solely based on electrical conductivity without prior soil property information.

scholarly journals Penetration resistance in a latosol under different moisture and penetration speeds

Revista CERES ◽  
2013 ◽  
Vol 60 (5) ◽  
pp. 715-721 ◽  
Author(s):  
Walter Francisco Molina Jr ◽  
Sônia Maria Stefano Piedade ◽  
Juarez Rennó Amaral
Keyword(s):  
Water Content ◽  
Bulk Density ◽  
Soil Water ◽  
Soil Water Content ◽  
Penetration Resistance ◽  
Density Variation ◽  
Cone Penetration ◽  
Soil Penetration Resistance ◽  
Cone Index

The soil penetration resistance has been used to represent the compaction situation and several authors have attempted to relate the cone index (CI) with the bulk density. The importance of using the CI as source of information for decisions in agricultural activities, livestock and forestry manner, has become increasingly larger, which requires more knowledge about the penetrometers and penetrographs behavior. This study aimed to verify, in controlled laboratory conditions, the influence of soil water content and cone penetration rate to obtain the cone index, when density variation occurs. The soil was compacted by compression through a universal press cylinder which was specially designed to produce the test specimens. Bulk densities were determined from samples taken from the test specimens and their moisture content. The CI values obtained were between 0.258 and 4.776 MPa, measured in 4 moistures and 7 soil densities with 3 penetration speeds. It was concluded that the determination of IC is strongly influenced by the soil moisture but the penetration speed variation, used in this study, was not sufficient to influence the IC determination. However, the decrease in soil water content may increase the sensitiveness to detect a variation in bulk density by the use of cone index.

Phosphate Diffusion Coefficients in Soil as Affected by Bulk Density and Water Content

1991 ◽  
Vol 154 (1) ◽  
pp. 53-57 ◽  
Author(s):  
P. B. S. Bhadoria ◽  
J. Kaselowsky ◽  
N. Claassen ◽  
A. Jungk
Keyword(s):  
Water Content ◽  
Bulk Density ◽  
Diffusion Coefficients

A simple method for the determination of ionic diffusion coefficients in flooded soils

2001 ◽  
Vol 15 (3) ◽  
pp. 511-518 ◽  
Author(s):  
P. J. Gardner ◽  
N. Flynn ◽  
E. Maltby
Keyword(s):  
Diffusion Coefficients ◽  
Ionic Diffusion ◽  
Flooded Soils ◽  
Simple Method

The drainage component of the water balance equation

Soil Research ◽  
1965 ◽  
Vol 3 (2) ◽  
pp. 95 ◽  
Author(s):  
CW Rose ◽  
WR Stern
Keyword(s):  
Water Balance ◽  
Water Content ◽  
Bulk Density ◽  
Balance Equation ◽  
Clay Soils ◽  
Swelling Clay ◽  
Water Balance Equation ◽  
Field Crops

A method is presented for determining the drainage term in the water balance equation, which may then be used to solve for evaporation from field crops. Questions concerning accuracy in determination of the drainage term are considered. Two special problems that arise in this context with swelling clay soils are discussed, namely, the variation of bulk density with water content, and the inference of in situ soil water suction from volumetric water content measurement.

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