Quantitative evaluation of the relative permittivity of artificial soil with altered soil types and water content

2021 ◽  
Author(s):  
Toshinori Kanemitsu ◽  
Yohei Morifuji ◽  
Kenji Kubota
Keyword(s):  
Water Content ◽  
Quantitative Evaluation ◽  
Relative Permittivity ◽  
Artificial Soil ◽  
Soil Types

scholarly journals Soil water retention curves for the major soil types of the Kruger National Park

Koedoe ◽  
2014 ◽  
Vol 56 (1) ◽  
Author(s):  
Robert Buitenwerf ◽  
Andrew Kulmatiski ◽  
Steven I. Higgins
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Water Content ◽  
Carbon Cycling ◽  
Soil Water ◽  
National Park ◽  
Soil Water Potential ◽  
Kruger National Park ◽  
Soil Types ◽  
Soil Moisture Retention

Soil water potential is crucial to plant transpiration and thus to carbon cycling and biosphere–atmosphere interactions, yet it is difficult to measure in the field. Volumetric and gravimetric water contents are easy and cheap to measure in the field, but can be a poor proxy of plant-available water. Soil water content can be transformed to water potential using soil moisture retention curves. We provide empirically derived soil moisture retention curves for seven soil types in the Kruger National Park, South Africa. Site-specific curves produced excellent estimates of soil water potential from soil water content values. Curves from soils derived from the same geological substrate were similar, potentially allowing for the use of one curve for basalt soils and another for granite soils. It is anticipated that this dataset will help hydrologists and ecophysiologists understand water dynamics, carbon cycling and biosphere–atmosphere interactions under current and changing climatic conditions in the region.

scholarly journals The dielectric calibration of capacitance probes for soil hydrology using an oscillation frequency response model

1998 ◽  
Vol 2 (1) ◽  
pp. 111-120 ◽  
Author(s):  
D. A. Robinson ◽  
C. M. K. Gardner ◽  
J. Evans ◽  
J. D. Cooper ◽  
M. G. Hodnett ◽  
...  
Keyword(s):  
Ionic Conductivity ◽  
Frequency Response ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Time Domain ◽  
Relative Permittivity ◽  
Time Domain Reflectometry ◽  
Physically Based ◽  
Capacitance Probe

Abstract. Capacitance probes are a fast, safe and relatively inexpensive means of measuring the relative permittivity of soils, which can then be used to estimate soil water content. Initial experiments with capacitance probes used empirical calibrations between the frequency response of the instrument and soil water content. This has the disadvantage that the calibrations are instrument-dependent. A twofold calibration strategy is described in this paper; the instrument frequency is turned into relative permittivity (dielectric constant) which can then be calibrated against soil water content. This approach offers the advantages of making the second calibration, from soil permittivity to soil water content. instrument-independent and allows comparison with other dielectric methods, such as time domain reflectometry. A physically based model, used to calibrate capacitance probes in terms of relative permittivity (εr) is presented. The model, which was developed from circuit analysis, predicts, successfully, the frequency response of the instrument in liquids with different relative permittivities, using only measurements in air and water. lt was used successfully to calibrate 10 prototype surface capacitance insertion probes (SCIPS) and a depth capacitance probe. The findings demonstrate that the geometric properties of the instrument electrodes were an important parameter in the model, the value of which could be fixed through measurement. The relationship between apparent soil permittivity and volumetric water content has been the subject of much research in the last 30 years. Two lines of investigation have developed, time domain reflectometry (TDR) and capacitance. Both methods claim to measure relative permittivity and should therefore be comparable. This paper demonstrates that the IH capacitance probe overestimates relative permittivity as the ionic conductivity of the medium increases. Electrically conducting ionic solutions were used to test the magnitude of this effect on the determination of relative permittivity. The response was modelled so that the relative permittivity, independent of ionic conductivity, could be determined in solutions with an electrical conductivity of up to 0.25 S m-1. It was found that a solution EC of less than 0.05 S m-1 had little impact on the permittivity measurement.

ANALYSIS OF EMPIRICAL COMPRESSION INDEX EQUATIONS USING THE WATER CONTENT

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Amir W. Al-Khafaji ◽  
Krishnanand Y. Maillacheruvu ◽  
Melissa Hoerber
Keyword(s):  
Water Content ◽  
Empirical Models ◽  
Soil Types ◽  
Data Sets ◽  
Regression Equations ◽  
Compression Index ◽  
Empirical Formulas ◽  
Wide Range ◽  
Compression Data ◽  
Water Contents

This paper proposes a new method to evaluate the reliability of published empirical formulas in terms of accuracy and applicability to different soil types. Different empirical models are proposed to properly approximate the compression index for a wide range of water contents and soil types. They were developed using a unique technique and a substantial number of published regression equations and compression data. Familiar empirical equations were examined for their reliability in predicting the compression index of clay for any water content. A comparison was made between available and newly-proposed empirical formulas using combined regression data sets compiled independently by several authors. The newly proposed empirical compression index equations are applicable to a wide range of clay soils, and in validating other published relationships. The degree of scatter and variations in the computed compression index values are minimized for any water content.

Iron oxides as a cause of GPR reflections

Geophysics ◽  
2002 ◽  
Vol 67 (2) ◽  
pp. 536-545 ◽  
Author(s):  
Remke L. Van Dam ◽  
Wolfgang Schlager ◽  
Mark J. Dekkers ◽  
Johan A. Huisman
Keyword(s):  
Electromagnetic Wave ◽  
Iron Oxide ◽  
Water Content ◽  
Iron Oxides ◽  
Wave Velocity ◽  
Relative Permittivity ◽  
Time Domain Reflectometry ◽  
Water Retention Capacity ◽  
Oxide Material ◽  
Retention Capacity

Iron oxides frequently occur as secondary precipitates in both modern and ancient sediments and may form bands or irregular patterns. We show from time-domain reflectometry (TDR) field studies that goethite iron-oxide precipitates significantly lower the electromagnetic wave velocity of sediments. Measured variations in magnetic permeability do not explain this decrease. The TDR measurements and a dielectric mixing model also show that neither electrical conductivity nor relative permittivity of the solid material are altered significantly by the iron-oxide material. From drying during all of the measurements, the amount of iron oxides appears to correlate with the volumetric water content, which is the result of differences in water retention capacity between goethite and quartz. These variations in water content control relative permittivity and explain the observed variation in electromagnetic wave velocity. Using 2-D synthetic radar sections, we show that the pattern of iron-oxide precipitation may have a profound influence on the GPR reflection configuration and can cause major difficulties in interpretation.

Quantitative Evaluation of Atopic Blepharitis by Scoring of Eyelid Conditions and Measuring the Water Content of the Skin and Evaporation from the Eyelid Surface

Cornea ◽  
2001 ◽  
Vol 20 (3) ◽  
pp. 255-259 ◽  
Author(s):  
Naoko Asano-Kato ◽  
Kazumi Fukagawa ◽  
Kazuo Tsubota ◽  
Kumiko Urayama ◽  
Shin-ichi Takahashi ◽  
...  
Keyword(s):  
Water Content ◽  
Quantitative Evaluation

scholarly journals Online appendix 2:Soil water retention curves for the major soil types of the Kruger National Park

Koedoe ◽  
2014 ◽  
Vol 56 (1) ◽  
Author(s):  
Robert Buitenwerf ◽  
Andrew Kulmatiski ◽  
Steven I. Higgins
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Water Content ◽  
Carbon Cycling ◽  
Soil Water ◽  
National Park ◽  
Soil Water Potential ◽  
Kruger National Park ◽  
Soil Types ◽  
Soil Moisture Retention

Soil water potential is crucial to plant transpiration and thus to carbon cycling and biosphere–atmosphere interactions, yet it is difficult to measure in the field. Volumetric and gravimetric water contents are easy and cheap to measure in the field, but can be a poor proxy of plant-available water. Soil water content can be transformed to water potential using soil moisture retention curves. We provide empirically derived soil moisture retention curves for seven soil types in the Kruger National Park, South Africa. Site-specific curves produced excellent estimates of soil water potential from soil water content values. Curves from soils derived from the same geological substrate were similar, potentially allowing for the use of one curve for basalt soils and another for granite soils. It is anticipated that this dataset will help hydrologists and ecophysiologists understand water dynamics, carbon cycling and biosphere–atmosphere interactions under current and changing climatic conditions in the region.

scholarly journals Effect of Soil Types on The Development of Matric Suction and Volumetric Water Content for Dike Embankment During Overtopping Tests

2018 ◽  
Vol 4 (3) ◽  
pp. 668 ◽  
Author(s):  
Marwan Adil Hassan ◽  
Mohd Ashraf Mohamad Ismail
Keyword(s):  
Water Content ◽  
Water Flow ◽  
Fine Particles ◽  
Side Wall ◽  
Matric Suction ◽  
Volumetric Water Content ◽  
Silty Sand ◽  
Soil Types ◽  
The Stability ◽  
The University

The resistance of dike materials has a great effect on the development of hydraulic engineering around the world. It helps to understand the mechanism of dike failure occurred due to the influence of hydraulics and Geotechnical parameters. The overtopping moment is one of the main failures that reduces the stability of the dike embankment through initiating the breach channel inside dike crest as a result of water flow above the downstream slope of the dike. Two spatial overtopping tests were conducted at in Hydraulic Geotechnical laboratories at the University Sains of Malaysia to observe the evolution of matric suction and volumetric water content for two soil types of sand and very silty sand soils. A pilot channel was cut in dike crest along the side wall of the small flume channel to represent the transition water flow from upstream into downstream slopes during overtopping test. The results indicated that the matric suction decreases due to the increase of volumetric water content during the saturation of dike body. The proportion increasing and decreasing of volumetric water content and matric suction is lower in very silty sand than those in sand soil due to the presence of fine particles in previous soil.

scholarly journals Online appendix 1: Soil water retention curves for the major soil types of the Kruger National Park

Koedoe ◽  
2014 ◽  
Vol 56 (1) ◽  
Author(s):  
Robert Buitenwerf ◽  
Andrew Kulmatiski ◽  
Steven I. Higgins
Keyword(s):  
Soil Moisture ◽  
Water Potential ◽  
Water Content ◽  
Carbon Cycling ◽  
Soil Water ◽  
National Park ◽  
Soil Water Potential ◽  
Kruger National Park ◽  
Soil Types ◽  
Soil Moisture Retention

Soil water potential is crucial to plant transpiration and thus to carbon cycling and biosphere–atmosphere interactions, yet it is difficult to measure in the field. Volumetric and gravimetric water contents are easy and cheap to measure in the field, but can be a poor proxy of plant-available water. Soil water content can be transformed to water potential using soil moisture retention curves. We provide empirically derived soil moisture retention curves for seven soil types in the Kruger National Park, South Africa. Site-specific curves produced excellent estimates of soil water potential from soil water content values. Curves from soils derived from the same geological substrate were similar, potentially allowing for the use of one curve for basalt soils and another for granite soils. It is anticipated that this dataset will help hydrologists and ecophysiologists understand water dynamics, carbon cycling and biosphere–atmosphere interactions under current and changing climatic conditions in the region.

Soil water changes under fallow-crop treatments in relation to soil type, rainfall and yield of wheat

1971 ◽  
Vol 11 (49) ◽  
pp. 236 ◽  
Author(s):  
JE Schultz
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Storage ◽  
South Australia ◽  
Soil Types ◽  
Soil Water Storage ◽  
Fallow Period ◽  
One Year ◽  
Water Contents ◽  
Soil Water Contents

Soil water changes under fallow (initial cultivation in spring), grassland (initial cultivation in autumn) and the succeeding wheat crops were recorded at two to three weekly intervals in three consecutive seasons in three soil types representing the range of wheat-growing soils in South Australia. Differences in water content between the two treatments developed soon after the start of fallowing due to the greater loss of water from grassland in spring. Rainfall during the fallow period contributed little to soil water storage except in one year when heavy spring rains were recorded. In some instances the water content in the fallowed soils at seeding was less than at the start of fallowing, but the fallowed soils consistently retained more water than the grassland soils. Soil water contents decreased after August of the crop year (end of tillering) and by harvest the wheat crops had commonly dried the soil to a depth of 150 cm. Fallow crops used more water and produced significantly higher wheat yields with a greater efficiency of water use in all trials.

scholarly journals Performance Evaluation of Volumetric Water Content and Relative Permittivity Models

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Muhammad Mukhlisin ◽  
Almushfi Saputra
Keyword(s):  
Performance Evaluation ◽  
Water Content ◽  
Bulk Density ◽  
Soil Water ◽  
Soil Water Content ◽  
Relative Permittivity ◽  
Secondary Data ◽  
Data Errors ◽  
Two Parameters ◽  
Soil And Water

In recent years many models have been proposed for measuring soil water content (θ) based on the permittivity (ε) value. Permittivity is one of the properties used to determineθin measurements using the electromagnetic method. This method is widely used due to quite substantial differences in values ofεfor air, soil, and water, as it allows theθvalue to be measured accurately. The performance of six proposed models with one parameter (i.e., permittivity) and five proposed models with two or more parameters (i.e., permittivity, porosity, and dry bulk density of soil) is discussed and evaluated. Secondary data obtained from previous studies are used for comparison to calibrate and evaluate the models. The results show that the models with one parameter proposed by Roth et al. (1992) and Topp et al. (1980) have the greatestR2data errors, while for the model with two parameters, the model proposed by Malicki et al. (1996) agrees very well with the data compared with other models.

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