Electrical Conductivity Of Saturated Paste Research Articles

Estimation of the electrical conductivity of saturated paste from soil–water extracts of coastal saline paddy soils using random forest and multiple regression models

Estimation of the electrical conductivity of saturated paste from soil–water extracts of coastal saline paddy soils using random forest and multiple regression models

Potassium and Brackish Water Irrigation Influence Electrical Conductivity, Potassium Dynamic, and Maize Yield in Coastal Saline Soil

ABSTRACT Brackish water irrigation builds up salinity in the root zone of crops resulting in osmotic stress, nutritional imbalance, and specific ion effect. The development of agro-technology to ameliorate the adverse effects of salt stress has received considerable attention. In this pot culture experiment, we used two types of irrigation water (SW0- normal water, EC- 0.5 dS m−1 and SW1-brackish water, EC- 4 dS m−1), two sources of potassium (K) fertilizers (F1-KCl and F2-K2SO4) and three doses of K (K1–0, K2–30, K3–60 mg kg−1) to study the effect of brackish water irrigation and K on soil saturated paste electrical conductivity (ECe), K dynamic and maize biomass yield in saline soil. The ECe in SW1 was increased significantly (P < .001) by 182% over SW0 but decreased with K application. The SW1 treatment significantly increased the release of non-exch.K by 27% over SW0 at 21 DASE (the day after seedling emergence). The addition of K3 significantly increased the water-soluble K (ws.K), exchangeable K (exch.K) and non-exch.K by 54, 93, and 9%, respectively over K1. The SW1K3 treatment significantly reduced ECe and increased maize biomass yield (24%) over SW1K1. The outcome of the study suggested that SW1 with K3 supports maize production in saline soil during winter.

Estimation of saturated paste electrical conductivity using three modelling approaches: Traditional dilution extracts; saturation percentage and artificial neural networks

Soil salinity is best estimated by saturated paste extract (ECe), the most reliable monitoring method to assess plant growth that is directly related to the field water content. However, this procedure is laborious and time-consuming, therefore, more convenient methods such as 1:5 soil: water extract is commonly used to estimate the ECe. Traditionally, a conversion factor (CF) based on a linear correlation between the diluted extract and ECe is employed for the estimation purposes. However, CF is affected by site-specific conditions. The objective of this research is to demonstrate a novel modelling approach that allows incorporating site-specific soil and irrigation water parameters to improve the accuracy of the ECe estimation. A total of 177 soil samples were collected from agricultural soils in the Jordan Valley representing different soil textures, crops and water qualities. ECe, EC1:5, clay and sand content, soil texture and saturation percentage (θSP) were determined. The collected data were used to construct models using three distinct approaches: traditional CF; incorporating θSP as a surrogate of soil texture to cater the CF to the site-conditions, and Artificial Neural Networks to incorporate site-specific parameters. The neural network model gave the most accurate estimates (R2 = 0.987, MSE = 2.39) and was able to handle the heteroscedasticity of the data. Meanwhile, the incorporation of θSP to estimate the CF that best represent the site has shown improved prediction quality over the traditional CF approach as it was more capable of handling the heteroscedasticity of the data. The neural network model allows for the incorporation of location-specific parameters and therefore offers a flexible tool for better management of agricultural soils. Although, this work used a case study location to demonstrate the concepts discussed, the approach is generalizable and can be easily adapted to other locations.

Establishing Relationship between Saturated Paste Electrical Conductivity (ECe) and Soil:Water Electrical Conductivity (EC1:2) in Some Swell-Shrink Soils of Nagpur District, Maharashtra

Soil salinity is a major environmental hazard which adversely affects plant growth, crop production, soil and water quality and agricultural productivity.Soil salinity is determined by measuring electrical conductivity of soil water suspension. Though saturation paste ECe closely relates with plant growth and development but its measurement is laborious and time-consuming specifically in clayey soils when large number of samples are analyzed. Measurement of EC1:2 (1:2 Soil: water suspension) is very quick and economical. Therefore, a need is felt to develop a relationship between ECe and EC1:2so that the values of EC1:2 could easily be related to ECe. For this, anexperiment was conducted on four soil series representing swell-shrink soils. Soils were artificially salinized with solutions (salt) of 0.2, 0.5, 1 and 2% of chloride salts (NaCl, CaCl2, MgCl2 and their mixture) and replicated three times. The results indicate that a significant relationship (r=0.96) exists between ECe and soil EC1:2and soil ECe can be reliably predicted from EC1:2 in swell-shrink soils.

Spatial variability of soil electrical conductivity in a small watershed on the Loess Plateau of China

Knowledge of soil electrical conductivity of saturated paste extract (ECe) pattern is important to effectively managing farmland and improving crop productivity. The objectives of this study were (1) to characterize the spatial patterns of ECe and electrical conductivity of saturated paste (ECs) and (2) to determine the factors that affect significantly in the estimation of soil ECe. Soil samples were taken at various soil depths (0.1, 0.2, 0.4, 0.6, and 0.8m) of 124 locations in a small watershed. Besides ECe and ECs, various soil, topographical, and vegetation properties were measured. Geostatistical techniques were used to characterize the spatial patterns of ECe and ECs. Ordinary least squares (OLS) and generalized least squares (GLS) models were used to perform multiple regression analyses between ECe and other properties. The OLS model belongs to a non-spatial regression, whereas the GLS model is a spatial regression which considers the autocorrelation in the residuals. Results showed that both ECe and ECs presented moderate variability at the watershed scale. The ECe presented weak to moderate spatial dependency, whereas the ECs presented moderate to strong spatial dependency. The ratio of ECe to ECs differed with soil texture, and it was greater for sand texture than for loam texture. A fair to moderate spatial agreement existed between ECe and ECs at all depths except for 0.2m, where ECe presented a more random distribution. Heteroscedasticity in the residuals between two land uses (grass land and shrub land) and autocorrelation in the residuals only existed at 0.4m soil layer where the GLS model did not improve significantly over the OLS model in terms of explaining variations in ECe. Electrical conductivity of saturated paste was the dominant factor in explaining ECe variation for all depths, while soil separate significant affected the estimation of ECe at 0.1m as well. It is concluded that ECs may be used as a surrogate for ECe especially for homogeneous soil textures. This would greatly reduce the work involved in ECe measurement due to the easier availability of ECs. Our study implies that ECe can be used as an index of soil fertility condition in this area. In addition, OLS model can be accurate enough to describe the relationships between ECe and other properties due to the absence of strong spatial dependency of ECe in this area.

SOIL SALINITY AND SODICITY APPRAISAL BY ELECTROMAGNETIC INDUCTION IN SOILS IRRIGATED TO GROW COTTON

ABSTRACTIn the Far West Texas region in the USA, long‐term irrigation of fine‐textured valley soils with saline Rio Grande River water has led to soil salinity and sodicity problems. Soil salinity [measured by saturated paste electrical conductivity (ECe)] and sodicity [measured by sodium adsorption ratio (SAR)] in the irrigated areas have resulted in poor growing conditions, reduced crop yields, and declining farm profitability. Understanding the spatial distribution of ECe and SAR within the affected areas is necessary for developing management practices. Conventional methods of assessing ECe and SAR distribution at a high spatial resolution are expensive and time consuming. This study evaluated the accuracy of electromagnetic induction (EMI), which measures apparent electrical conductivity (ECa), to delineate ECe and SAR distribution in two cotton fields located in the Hudspeth and El Paso Counties of Texas, USA. Calibration equations for converting ECa into ECe and SAR were derived using the multiple linear regression (MLR) model included in the ECe Sampling Assessment and Prediction program package developed by the US Salinity Laboratory. Correlations between ECa and soil variables (clay content, ECe, SAR) were highly significant (p ≤ 0·05). This was further confirmed by significant (p ≤ 0·05) MLRs used for estimating ECe and SAR. The ECe and SAR determined by ECa closely matched the measured ECe and SAR values of the study site soils, which ranged from 0·47 to 9·87 dS m−1 and 2·27 to 27·4 mmol1/2 L−1/2, respectively. High R2 values between estimated and measured soil ECe and SAR values validated the MLR model results. Results of this study indicated that the EMI method can be used for rapid and accurate delineation of salinity and sodicity distribution within the affected area. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Edaphic Characterization, Water and Salt Translocation in Saline Marsh at Local Scale in Songnein Plain, Northeast China

The degradation of saline marsh in Songnen plain was controlled by many factors. Based on in-situ observation and laboratory analysis, soil properties and matters translocation in Zhalong wetland at local scale as affected by freeze and thaw action was explored. Results show that within the study plot, 1500 m in distance, but varying only 80 cm in altitude, existed four types of soils i.e. Shallow-horizon Alkalic Halosols (SAH), Crust Alkalic Halosols (CAH) and Para-alkalic Dark-Aquic Cambosols (PDC) and Sodic Hapli-Orthic Gleyosols (SHG). High content total porosity with amounts to 62% in surface horizon in marsh would help to water conservation and wetland formation. In contrast, large rate of silt or clay in texture in alkali soil and meadow soil constrain the water content in topsoil, i.e. the saturated water content 0-30 cm horizon of meadow soil and alkali soil were merely 0.83 and 0.7 m3 m-3. Residues &amp; roots in surface layer of SHG expand the period of freezing phase as long as 9 months comparing to 7 months in SAH, and maximum freezing fringe in the former was 24 cm deeper than the latter (178 cm versus 154 cm). Seasonal freeze and thaw action has obvious influence on water storage in topsoil in saline marsh, leading different of soil succession therein. Soil moisture content in the surface layer of marsh increased from 2.05 to 2.62 m3 m-3(over-saturated), but no obvious change in PDC and Alkali soils. In contrast, electrical conductivity of saturated paste in SAH and CAH increased from 6.5 to above 10 dS m-1. Therefore, it did not accord with the practical situation of Northeast China as that of strong evaporation was the only cause that caused saline marsh alkalinization. Protecting the vegetation or restoring surface coverage by plant in saline land in spring may help land dealkalization in high latitude arid &amp; semiarid regions.

Delineating Salinity and Sodicity Distribution in Major Soil Map Units of El Paso, Texas, Using Electromagnetic Induction Technique

A majority of the irrigated area in the Trans-Pecos basin in the United States is affected by both salinity and sodicity that affect the long-term viability of irrigated agriculture in the region. Accurate information on spatial distribution of salinity and sodicity in the irrigated areas at a field scale is necessary for developing effective management practices. Currently, information on the amount and the distribution of salts within the irrigated areas of the Trans-Pecos basin is not available. Conventional method of soil salinity (saturated paste electrical conductivity) and sodicity (sodium adsorption ratio) assessment at a high spatial resolution is expensive, time consuming, and labor intensive. Electromagnetic induction technique can offer a low-cost, noninvasive, and rapid alternative for determining the spatial distribution of both salinity and sodicity. In this study, we evaluated the accuracy of EMI technique to delineate salt and sodicity distribution within a 12-ha study site that had all four dominant soil map units (Saneli-clayey over sandy or sandy-skeletal, montmorillonitic [calcareous], thermic Vertic Torrifluvents; Tigua-very fine, montmorillonitic (calcareous), thermic Vertic Torrifluvents; Harkey-coarse-silty, mixed [calcareous], thermic Typic Torrifluvents; Glendale-fine-silty, mixed [calcareous], thermic Typic Torrifluvents) of the Trans-Pecos basin. Salinity and sodicity values estimated by EMI technique ranged from 0.73 to 10.55 dS m−1 and sodium adsorption ratio ranged from 1.2 to 21.6 mmol1/2 L−1/2. Results of this project indicated that the EMI technique can produce accurate information on salinity distribution. Soil clay and moisture content at the time of the survey strongly influenced the accuracy of the EMI technique.

Estimation of Saturated Paste Extracts’ Electrical Conductivity from 1:5 Soil/Water Suspension and Gypsum

Texture and salt type influence the relationships between saturated paste electrical conductivity (ECe) and EC of other soil/water ratios. The objectives of this study were to develop and validate relationships between ECe and EC1:5 suspension for soils in Yazd Province and evaluate the effects of soil texture and gypsum on those relationships. Three hundred twenty-two soil samples were collected, of which 272 (all data) were used to develop the models and 50 were used to validate them. The soils were divided into two general textural categories of coarse and fine and two categories of with (G) and without gypsum (NG). Gypsum content had a stronger impact on the accuracy of the suspension method in predicting ECe than texture. The ECe = 5.60 EC1:5 − 4.37 and ECe = 5.37 EC1:5 + 0.57 models are recommended for soils with and without gypsum, respectively. The methodology can be implemented in other regions, particularly if gypsum is present.

Usage of sewage effluent in irrigation of some woody tree seedlings. Part 3: Swietenia mahagoni (L.) Jacq.

A pot experiment was investigated to study the effect of sewage irrigation treatments (primary and secondary effluents) compared with tap water on the growth and chemical constituents of mahogany seedlings ( Swietenia mahagoni (L.) Jacq.) as well as soil chemical properties. The experiment was conducted at a greenhouse in the nursery of Timber Trees Research Department of Sabahia, Horticultural Research Station in Alexandria, Egypt, from June 2003 to December 2004 for three irrigation periods (6, 12 and 18 months). The sewage effluent waters were taken from oxidation ponds located in New Borg EL-Arab city and used directly for irrigation. The primary effluent treatment was superior than other treatments in improving the growth parameters (plant height, stem diameter, leaf area, leaves number, fresh and dry weights of leaves, shoots and roots and shoot/root ratio) and showed the highest concentration and total uptake of N, P, K, Cd, Ni, Pb and Fe in plant parts, followed by secondary effluent then tap water. The data revealed that soil salinity in terms of electrical conductivity of saturated paste (EC), CaCO 3%, organic matter% and soluble anions and cations were influenced significantly by primary or secondary effluent treatment. The data also showed that the use of sewage effluent for irrigation increased N, P, K and DTPA-extractable-heavy metals (Cd, Cu, Ni, Pb, Fe, Mn and Zn). The effects of sewage effluent on growth parameters and elements content in plant parts and treated soil were more pronounced as water treatments were used for long period. The results suggested that the use of sewage effluent in irrigating mahogany trees grown on calcareous sandy loam soil was an important agriculture practice for improving soil properties, increasing fuel and timber production, and is an economic and safe way to dispose wastewaters.

Assessment of different soil to water ratios (1:1, 1:2.5, 1:5) in soil salinity studies

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 measured in saturated paste extract. Sandy, loamy, and clay textured soils were artificially salinized for one month by capillarity with different saline water of 0.02 (de-ionized water), 0. 4 (tap water), 2, 4, 8 and 16 dS/m. The saline waters were prepared by adding various amounts of NaCl, KCl, and CaCl 2 into tap water for each level of salinity to obtain desired salinity level. Having measured electrical conductivity, the extracts were analyzed for Na +, K +, Ca 2+, Mg 2+, Cl −, CO 3 2−, and HCO 3 −. The results showed that highly significant correlation exists between values measured in saturated paste extracts and in extracts of different soil to water ratios for electrical conductivity and ion concentrations. Based on the results obtained, it was concluded that extracts of (1:1), (1:2.5) or (1:5) soil to water ratios can be used to estimate saturated paste electrical conductivity and ion concentrations of soils.

Gypsum and Texture Effects on the Estimation of Saturated Paste Electrical Conductivity by Two Extraction Methods

Texture and salt type can influence the relationships between saturated paste electrical conductivity (ECe) and EC of other soil/water ratios. The objectives of this study were to develop and validate relationships among ECe, EC1∶2, and EC1∶5 for soils in Yazd Province, and evaluate the effects of texture and gypsum on those relationships. Two hundred thirty‐six soil samples were collected, of which 200 were used to develop and 36 were used to validate the models. The soils were divided into two textural categories, coarse and fine, and two categories, with and without gypsum. The 1∶2 procedure predicted ECe of slightly more than 1∶5. Gypsum content had stronger impact on the accuracy of models in predicting ECe than texture. The ECe=4.0723EC1∶2−5.7135 and ECe=3.5142EC1∶2+0.7615 models are recommended for soil with and without gypsum, respectively. The methodology can be implemented in any other region, particularly if gypsum is present.

Revegetation of waste fly ash landfills in a semiarid environment

This study investigated vegetation strategies for a fly ash landfill in a semi-arid environment. Ten plant species adapted to the local climate were initially evaluated for their germination characteristics in various mixtures of Tivoli fine sand, fly ash, and cattle manure. Alkali sacaton (native, Sporobolus airoides (Torr.) Torr.), blue grama (native, Bouteloua gracilis (H.B.K.) Lag. Ex Griffiths), a forage sorghum (variety Canex, Sorghum bicolor (L.) Moench), sand bluestem (variety Woodward, Andropogon hallii Hack.), and sideoats grama variety El Reno, Bouteloua curtipendula (michx.) Torr.) were selected for further evaluation. Concurrently, mixtures were evaluated to determine the effects of the soil amendments on soil saturated paste electrical conductivity (EC) and pH. The addition of even 50 g kg−1 fly ash increased EC values above 4.0 dS m−1, indicating salt tolerant species may be needed. Six mixtures were selected for use in a greenhouse study and for further study of moisture retention characteristics. Using an X/Y format, where X is fly ash content and Y is manure content (g kg−1) and the balance of the mixture was Tivoli fine sand, those mixtures were 0/0, 200/0, 200/100, 200/200, 100/100, and 300/100. The addition of manure provided ample quantities of plant nutrients. Alkali sacaton was the only plant specie not adversely affected by the addition of fly ash. For biomass production, height, vigor and leaf tip burn, all remaining species had significantly better growth or ratings with 0/0 as compared to any other mixture. Soil moisture retention characteristics of the Tivoli fine sand can be significantly changed through amendment with fly ash or manure. Sixty cm of Tivoli sand was estimated to have the same available water holding capacity as 45 cm of 200/0, 39 cm of 200/100, 34 cm of 200/200, 47 cm of 100/100, and 33 cm of 300/100.

Revegetation of waste fly ash landfills in a semiarid environment

This study investigated vegetation strategies for a fly ash landfill in a semi-arid environment. Ten plant species adapted to the local climate were initially evaluated for their germination characteristics in various mixtures of Tivoli fine sand, fly ash, and cattle manure. Alkali sacaton (native, Sporobolus airoides (Torr.) Torr.), blue grama (native, Bouteloua gracilis (H.B.K.) Lag. Ex Griffiths), a forage sorghum (variety Canex, Sorghum bicolor (L.) Moench), sand bluestem (variety Woodward, Andropogon hallii Hack.), and sideoats grama variety El Reno, Bouteloua curtipendula (michx.) Torr.) were selected for further evaluation. Concurrently, mixtures were evaluated to determine the effects of the soil amendments on soil saturated paste electrical conductivity (EC) and pH. The addition of even 50 g kg-1 fly ash increased EC values above 4.0 dS m-1, indicating salt tolerant species may be needed. Six mixtures were selected for use in a greenhouse study and for further study of moisture retention characteristics. Using an X/Y format, where X is fly ash content and Y is manure content (g kg-1) and the balance of the mixture was Tivoli fine sand, those mixtures were 0/0, 200/0, 200/100, 200/200, 100/100, and 300/100. The addition of manure provided ample quantities of plant nutrients. Alkali sacaton was the only plant specie not adversely affected by the addition of fly ash. For biomass production, height, vigor and leaf tip burn, all remaining species had significantly better growth or ratings with 0/0 as compared to any other mixture. Soil moisture retention characteristics of the Tivoli fine sand can be significantly changed through amendment with fly ash or manure. Sixty cm of Tivoli sand was estimated to have the same available water holding capacity as 45 cm of 200/0, 39 cm of 200/100, 34 cm of 200/200, 47 cm of 100/100, and 33 cm of 300/100.

Soil and groundwater chemistry and vegetation distribution in a desert playa, Owens Lake, California

Generation of fine particulate dust (PM10)from the Owens Lake play a creates a severe air pollution hazard in the western Great Basin of the United States. One proposed mitigation strategy involves establishment of native vegetation to stabilize and trap fugitive sand. This study investigated soil and groundwater chemistry and the distribution of native plant species in relation to salts and toxic ions in the soil and groundwater along four transects from vegetated dunes or shorelines to nonvegetated playa surfaces. Soluble salts in soil extracts along all four transects were dominated by Na+(mole fraction = 0.43–0.47), HCO3/CO3 2‐ (020–026), and Cl‐ (0.15–022). Distichlis spicata (L.) E. Greene and Atriplex parryi S. Watson were found at locations with very high salt concentrations (44–77 dS m‐1 saturated paste electrical conductivity EC). The ultimate limitation to plant distribution, however, appears to result from shallow anoxic groundwater restricting rooting depth. Groundwater chemistry was characterized by high pH (93–10), EC (3–54 dS m‐1), and sodium adsorption ratio (46–1223), and low redox potential (Eh = 7 to ‐240 mV). Shallow anoxic groundwater restricted the rooting zone of both D. spicata and A. parryi, and no vegetation was found when anoxic conditions were within 70 cm of the surface. An oxidized rooting zone greater than ∼1.5 m depth was present where cover of D. spicata and A. parryi was adequate for sand stabilization. Artificial dunes created with sand fences appear to be a substrate from which salts and borate‐B could be leached to levels tolerable by these species, and at the same time these raised microsites would provide a rooting zone of adequate depth for persistence of either naturally or artificially established native species.

Physical and Chemical Properties of Coal Refuse from Southwest Virginia

AbstractCoal refuse is difficult to reclaim due to high potential acidity, very coarse texture, low water retention, and fertility. This study was undertaken to determine the physical and chemical properties and the reclamation potential of samples from 27 coal refuse piles of varying age. Selected physical and chemical properties varied widely across this sample set. The &gt;2 mm fragment content was 60%, and the average texture of the &lt;2 mm fraction was a sandy loam with 15% clay. The mean water retention difference, (−1.50 to −0.030 MPa), on a whole sample basis was 0.08 kg water/kg refuse. The pH varied from 3.0 to 8.3 due to differences in the amounts and reactivity of pyritic minerals in refuse. Older piles generally had lower pH values than more recent piles. The saturated paste electrical conductivity (EC) was higher in the younger refuse due to active pyrite oxidation. A 5:1 water to soil (w/w) extract shows promise as an effective screen for samples with potentially high EC values. Coal refuse was generally low in available P and B. Total elemental analysis revealed that Si, Al, Fe, and K were the most abundant elements. The physical factor most limiting to plant growth is likely to be low water holding capacity, while low pH was found to be the chemical factor most limiting to plant survival. These findings indicate that some refuse piles may be suitable for direct seeding, but many will require heavy lime and/or organic treatments for successful reclamation.

CONVERSION OF ELECTROMAGNETIC INDUCTANCE READINGS TO SATURATED PASTE EXTRACT VALUES IN SOILS FOR DIFFERENT TEMPERATURE, TEXTURE, AND MOISTURE CONDITIONS

Linear equations were developed for converting electromagnetic induction readings (ECa) from EM38 meters to saturated paste electrical conductivity values (ECc). To correlate EM38 readings with measured ECe values, field sites representing a range of salinity conditions were sampled in 0.30-m increments to a depth of 1.5 m. Adapting a weighting procedure based on the EM38 meter's response to depth, ECe values were condensed into a single weighted value. The weighted ECe values were linearly correlated with temperature-corrected ECa readings. Equations were designed for soils of various textures under varying temperature and moisture conditions. For accurate ECa to ECe conversions, soil temperature correction of ECa is essential. When a frozen layer is present, EM38 readings are unreliable. EM38 horizontal and vertical modes show different ECa readings for the same depth-weighted ECe. Variability of ECa to ECe conversion was greater on coarse-textured than medium- or fine-textured soils. Available soil moisture should be above 30% for accurate ECe determinations from ECa readings. Key words: Salinity methods, soil salinity, saturated paste extract method, electromagnetic inductance meters, soil temperature

A RAPID METHOD FOR ESTIMATING WEIGHTED SOIL SALINITY FROM APPARENT SOIL ELECTRICAL CONDUCTIVITY MEASURED WITH AN ABOVEGROUND ELECTROMAGNETIC INDUCTION METER

This study presents a method for calibrating electromagnetic induction instrument readings with saturated paste electrical conductivity (ECe) for field mapping purposes. Each meter reading represents an integration of the apparent soil electrical conductivity (ECa) over the meter’s response depth. To correlate the meter readings with measured ECe within soil depth increments, several pedons representing a range of soil salinity for the survey area were sampled in 30-cm increments to a depth corresponding to the meter response. A weighting procedure based on the meter response-depth function was developed to condense the multiple ECe by depth measurements into a single weighted area specific value. These values were correlated with the apparent soil electric conductivity from the electromagnetic induction instrument by simple linear regression. This technique is designed for soil association of similar parent materials. The resulting regression equation yields a quick reliable equation that avoids complex mathematics and converts the instrument readings into weighted forms of commonly used saturated paste electrical conductivity values. Key words: Soil survey, electrical resistance