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A calibrated Four-Electrode Probe (FEP) was used for inexpensive and indirect determinations of salinity-sensor Electrical Conductivity (EC) in a plot at Cauto Valley, Cuba. Two transects were made in the North-South (N-S) and East-West (E-W) directions. Laboratory measurements of soil EC were also made from samples taken on a 50-m spaced square grid. A linear semivariogram was obtained for the salinity-sensor...
With the aim of estimating certain physico-chemical properties of soil-saturation extracts from electrical conductivity, we prepared saturation extracts from 67 soil samples having different quantitative and qualitative salt contents. The solution of each saturation extract was vacuum pumped, and used to determine the electrical conductivity (EC), electrical conductivity calculated (EC c ),...
Salt-affected soils could produce useful forages when irrigated with saline drainage water. To assess the productive potential and sustainability of using drainage water for forage production, a saline-sodic site (32.4 ha) in California's San Joaquin Valley was characterized for soil quality. The objectives were (1) to spatially characterize initial soil physicochemical properties relevant to maintaining...
Relative to montmorillonitic or kaolinitic soils, volcanic soils have atypical dielectric characteristics that interfere with the applicability of the Time Domain Reflectometry (TDR) technique for soil moisture (θ) determination when common, empirical calibration equations are used. This particular dielectric response affects estimation of salinity in volcanic soils. Six TDR-based methods to estimate...
The soil of a section of the farm Broodkraal, in the South Western Cape province of South Africa, was sampled on a 45 by 50.5 m grid to model spatial variation of salinity and predicts the amount of salts lost through irrigation. Sampling was done to a depth of 45 cm. The sampling included vineyards of different age that varied between 2 and 5 years since the first irrigation application. Salts mobilized...
This study evaluated the stability of water-suspended biosolid colloids fractionated from municipal and agricultural wastes and their transportability through undisturbed soil monoliths. The aim of the study was to assess potential risks posed by dispersed biosolid colloid particles as carriers of contaminants associated with organic waste amendments applied to soils. All biosolid colloids showed...
The performance of ground-penetrating radar (GPR) in soils strongly depends on soil electrical conductivity. Soils having high electrical conductivity rapidly attenuate radar energy, which restricts penetration depths and severely limits the effectiveness of GPR. Factors influencing the electrical conductivity of soils include the amount and type of salts in solution and the clay content. The Ground-Penetrating...
Time Domain Reflectometry (TDR) is a widespread technique for measurement of soil water content (SWC). The main assumption behind the use of Time Domain Reflectometry (TDR) is of negligible losses, therefore assuming that only the real part determines the value of the TDR-measured apparent dielectric permittivity. This assumption does not hold for soils where surfaces are conductive (clay soils) or...
Soil salinity is one of the limiting factors of agricultural productivity. It is essential to determine the soil salinity in a reliable and yet relatively easy method. This experimental study was carried out to assess the possibilities of measuring electrical conductivity as well as ion concentrations in the extracts of different soil to water ratios, (1:1, 1:2.5, 1:5), and to compare them with those...
Livestock manure application increases soil nutrient levels, enhancing their bioavailability, but potentially increasing environmental concerns. This study investigates the residual effects of long-term cattle feedlot manure applications to continuously cropped fields under semi-arid conditions on soil properties, crop yields and rate of soil recovery after manure application ceases. Solid cattle...
Accurate measurement of soil moisture (θ), bulk electrical conductivity (σ b ), and porewater electrical conductivity (σ w ) in the vadose zone is critical for a wide range of environmental monitoring applications. The use of combined dielectric probes allows for the automated collection of high-resolution, long-term data, however variation in probe response to different soil types...
Mining causes drastic disturbances in landscape and soil properties, and reclamation can restore soil quality over time. Thus, assessing changes in properties of reclaimed mine soils is essential to understanding the effects of the reclamation techniques. This study was aimed at quantifying the effects of mining and reclamation processes on physical and chemical properties of reclaimed soils for three...
Most soil properties sensed on-the-go (e.g., electrical conductivity, capacitance, optical reflectance, mechanical resistance and soluble ion activity) are not directly related to the agronomic parameters used to make management decisions. Nonetheless, these sensors provide an opportunity to obtain fine-resolution data about the spatial variability of soil in agricultural fields, rapidly and at a...
Conducting a 1:5 soil:water extract to measure electrical conductivity (EC) is an approach to assess salinity and has been the preferred method in Australia, but not commonly used in the United States where the 1:1 soil to water ratio is preferred. The objectives of this research were to 1) compare methods of agitation for determining EC 1:5 and 2) to determine optimal times for equilibration...
In this paper a comparison of two models predicting electrical conductivity of the soil pore water (σ p ) is attempted using data of soil dielectric permittivity ε and bulk soil electrical conductivity σ b , as these are obtained by two dielectric sensors the WET and the 5TE. These models are: The linear model by Hilhorst and the model of Rhoades. The evaluation of the models was performed...
Soil salinity is widespread in a variety of environments, and land managers need to map its severity and extent both laterally and vertically. In this research we explore the inversion of apparent electrical conductivity (EC a ) measured with an EM38 using a linear model and Tikhonov regularization to model electrical conductivity (σ) profiles in a saline paddy field in the Yangtze delta of...
Apparent soil electrical conductivity (EC a ), a widely used proximal soil sensing technology, is related to several important soil properties, including salinity, clay content, and bulk density. Particularly in layered soils, interpretation of EC a variations would be enhanced with better calibrations to depth-wise variations in these soil properties. Thus, the objective of this research...
The study investigated proximal sensor data fusion for topsoil clay mapping on a 22hectare agricultural field in southwest Sweden. Eight different predictor sets and two different prediction methods were tested in an orthogonal design. The predictor sets were different combinations of proximally measured gamma (γ) ray spectrometry and apparent electrical conductivity (ECa), four terrain attributes...
GEOPHILUS ELECTRICUS (nickname GEOPHILUS) is a novel system for mapping the complex electrical bulk resistivity of soils. Rolling electrodes simultaneously measure amplitude and phase data at frequencies ranging from 1mHz to 1kHz. The sensor's design and technical specifications allow for measuring these parameters at five depths of up to ca. 1.5m. Data inversion techniques can be employed to determine...
The archaeological evaluation of landscapes in the framework of developer-led archaeology is often based on extensive trenching programmes complemented with auger surveys in wetland environments. During the archaeological evaluation of a 90ha polder site in the north-west of Belgium, a mobile multi-receiver electromagnetic induction (EMI) survey was used as a main prospecting technique. The use of...
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