scholarly journals Assessing the dynamics of soil salinity with time-lapse inversion of electromagnetic data guided by hydrological modelling

2021 ◽  
Vol 25 (3) ◽  
pp. 1509-1527
Author(s):  
Mohammad Farzamian ◽  
Dario Autovino ◽  
Angelo Basile ◽  
Roberto De Mascellis ◽  
Giovanna Dragonetti ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Soil Salinity ◽  
Electromagnetic Induction ◽  
Irrigation System ◽  
Time Lapse ◽  
Hydrological Modelling ◽  
Irrigated Agriculture ◽  
Field Assessment ◽  
Apparent Electrical Conductivity ◽  
Spatio Temporal

Abstract. Irrigated agriculture is threatened by soil salinity in numerous arid and semi-arid areas of the world, chiefly caused by the use of highly salinity irrigation water, compounded by excessive evapotranspiration. Given this threat, efficient field assessment methods are needed to monitor the dynamics of soil salinity in salt-affected irrigated lands and evaluate the performance of management strategies. In this study, we report on the results of an irrigation experiment with the main objective of evaluating time-lapse inversion of electromagnetic induction (EMI) data and hydrological modelling in field assessment of soil salinity dynamics. Four experimental plots were established and irrigated 12 times during a 2-month period, with water at four different salinity levels (1, 4, 8 and 12 dS m−1) using a drip irrigation system. Time-lapse apparent electrical conductivity (σa) data were collected four times during the experiment period using the CMD Mini-Explorer. Prior to inversion of time-lapse σa data, a numerical experiment was performed by 2D simulations of the water and solute infiltration and redistribution process in synthetic transects, generated by using the statistical distribution of the hydraulic properties in the study area. These simulations gave known spatio-temporal distribution of water contents and solute concentrations and thus of bulk electrical conductivity (σb), which in turn were used to obtain known structures of apparent electrical conductivity, σa. These synthetic distributions were used for a preliminary understanding of how the physical context may influence the EMI-based σa readings carried out in the monitored transects as well as being used to optimize the smoothing parameter to be used in the inversion of σa readings. With this prior information at hand, we inverted the time-lapse field σa data and interpreted the results in terms of concentration distributions over time. The proposed approach, using preliminary hydrological simulations to understand the potential role of the variability of the physical system to be monitored by EMI, may actually allow for a better choice of the inversion parameters and interpretation of EMI readings, thus increasing the potentiality of using the electromagnetic induction technique for rapid and non-invasive investigation of spatio-temporal variability in soil salinity over large areas.

scholarly journals Assessing the dynamics of soil salinity with time-lapse inversion of electromagnetic data guided by hydrological modelling

2020 ◽  
Author(s):  
Mohammad Farzamian ◽  
Dario Autovino ◽  
Angelo Basile ◽  
Roberto De Mascellis ◽  
Giovanna Dragonetti ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Water Content ◽  
Soil Salinity ◽  
Time Lapse ◽  
Solute Concentration ◽  
Hydrological Modelling ◽  
Irrigated Agriculture ◽  
Field Assessment ◽  
The World ◽  
Spatio Temporal

Abstract. Irrigated agriculture is threatened by soil salinity in numerous arid and semiarid areas of the world, chiefly caused by the use of highly salinity irrigation water, compounded by excessive evapotranspiration. Given this threat, efficient field assessment methods are needed to monitor the dynamics of soil salinity in salt-affected irrigated lands and evaluate the performance of management strategies. In this study, we report on the results of an irrigation experiment with the main objective of evaluating time-lapse inversion of electromagnetic induction (EMI) data and hydrological modelling in field assessment of soil salinity dynamics. Four experimental plots were established and irrigated 12 times during a two-month period, with water at four different salinity levels (1, 4, 8 and 12 dS m−1) using a drip irrigation system. Time-lapse apparent electrical conductivity (σa) data were collected 6 times during the experiment period using a CMD Mini-Explorer. Prior to inversion of time-lapse σa data, a numerical experiment was performed by 2D simulations of the water and solute infiltration and redistribution process. The obtained potential spatio-temporal distributions of water content, solute concentration and bulk electrical conductivity (σb) assisted in understanding of how solute concentration and water content changes during the experiment influence σb distribution as well as optimizing the time-lapse inversion parameters for resolving σb changes in this experiment. Finally, we inverted the time-lapse field σa data and interpreted the results in terms of concentration distributions over time. Our investigation shows that EMI measurements and suitable modelling techniques allow for rapid and non-invasive investigation of spatio-temporal variability in soil salinity over large areas. Their effectiveness and relatively low cost make them appealing for management of water irrigation in salinity-threatened regions of the world.

scholarly journals Field-Scale Characterization of Spatio-Temporal Variability of Soil Salinity in Three Dimensions

2020 ◽  
Vol 12 (24) ◽  
pp. 4043
Author(s):  
Hongyi Li ◽  
Xinlu Liu ◽  
Bifeng Hu ◽  
Asim Biswas ◽  
Qingsong Jiang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Soil Salinity ◽  
Three Dimensions ◽  
Soil Core ◽  
Arid Areas ◽  
Field Scale ◽  
Natural Factors ◽  
Secondary Salinity ◽  
Spatio Temporal ◽  
Semi Arid

Information on spatial, temporal, and depth variability of soil salinity at field and landscape scales is important for a variety of agronomic and environment concerns including irrigation in arid and semi-arid areas. However, challenges remain in characterizing and monitoring soil secondary salinity as it can largely be impacted by managements including irrigation and mulching in addition to natural factors. The objective of this study is to evaluate apparent electrical conductivity (ECa)-directed soil sampling as a basis for monitoring management-induced spatio-temporal change in soil salinity in three dimensions. A field experiment was conducted on an 18-ha saline-sodic field from Alar’s Agricultural Science and Technology Park, China between March, and November 2018. Soil ECa was measured using an electromagnetic induction (EMI) sensor for four times over the growing season and soil core samples were collected from 18 locations (each time) selected using EMI survey data as a-priori information. A multi-variate regression-based predictive relationship between ECa and laboratory-measured electrical conductivity (ECe) was used to predict EC with confidence (R2 between 0.82 and 0.99). A three-dimensional inverse distance weighing (3D-IDW) interpolation clearly showed a strong variability in space and time and with depths within the study field which were mainly attributed to the human management factors including irrigation, mulching, and uncovering of soils and natural factors including air temperature, evaporation, and groundwater level. This study lays a foundation of characterizing secondary salinity at a field scale for precision and sustainable management of agricultural lands in arid and semi-arid areas.

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

1986 ◽  
Vol 66 (2) ◽  
pp. 315-321 ◽  
Author(s):  
N. C. WOLLENHAUPT ◽  
J. L. RICHARDSON ◽  
J. E. FOSS ◽  
E. C. DOLL
Keyword(s):  
Electrical Conductivity ◽  
Soil Salinity ◽  
Electrical Resistance ◽  
Electromagnetic Induction ◽  
Soil Depth ◽  
Soil Survey ◽  
Soil Electrical Conductivity ◽  
Simple Linear Regression ◽  
Survey Area ◽  
Parent Materials

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

scholarly journals Electromagnetic Induction Measurements for Investigating Soil Salinization Caused by Saline Reclaimed Water

Atmosphere ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 73
Author(s):  
Lorenzo De Carlo ◽  
Gaetano Alessandro Vivaldi ◽  
Maria Clementina Caputo
Keyword(s):  
Electrical Conductivity ◽  
Soil Salinity ◽  
Electromagnetic Induction ◽  
Reclaimed Water ◽  
Soil Salinization ◽  
Repeated Measurements ◽  
Soil Electrical Conductivity ◽  
Geophysical Research ◽  
Soil Response ◽  
Short Period

This paper focused on the use of electromagnetic induction measurements in order to investigate soil salinization caused by irrigation with saline reclaimed water. An experimental activity was carried out during the growing season of tomato crop in order to evaluate expected soil salinization effects caused by different saline agro-industrial wastewaters used as irrigation sources. Soil electrical conductivity, strictly related to the soil salinity, has been monitored for three months by means of Electromagnetic Induction (EMI) measurements, and evident differences in the soil response have been observed. The study highlighted two aspects that can improve soil investigation due to the utilization of geophysical tools. First, EMI data can map large areas in a short period of time with an unprecedented level of detail by overcoming practical difficulties in order to massively sample soil. At the same time, repeated measurements over time allow updating real-time soil salinity maps by using accurate correlations with soil electrical conductivity. This application points out how integrated agro-geophysical research approaches can play a strategic role in agricultural saline water management in order to prevent soil salinization risks in medium to long-term periods.

scholarly journals Field Comparison of Electrical Resistance, Electromagnetic Induction, and Frequency Domain Reflectometry for Soil Salinity Appraisal

Soil Systems ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 61
Author(s):  
Fernando Visconti ◽  
José Miguel de Paz
Keyword(s):  
Electrical Conductivity ◽  
Frequency Domain ◽  
Soil Salinity ◽  
Electrical Resistance ◽  
Electromagnetic Induction ◽  
Linear Regression Models ◽  
Bulk Electrical Conductivity ◽  
Mass Fractions ◽  
Frequency Domain Reflectometry ◽  
Different Depths

By using different physical foundations and technologies, many probes have been developed for on-site soil salinity appraisal in the last forty years. In order to better understand their respective technical and practical advantages and constraints, comparisons among probes are needed. In this study, three different probes, based on electrical resistance (ER), electromagnetic induction (EMI), and frequency domain reflectometry (FDR), were compared during a field survey carried out in a large salt-threatened agricultural area. Information about the soil bulk electrical conductivity (σb) at different depths was obtained with each of the probes and, additionally, other soil properties were also measured depending on the specifications of each instrument and, moreover, determined in samples. On average, the EMI and FDR techniques could be regarded as equivalent for σb measurement, whereas ER gave higher σb values. Whatever the case, EMI, and also ER, had to be supplemented with information about soil clay, organic matter, and water mass fractions to attain, despite this effort, poor soil salinity estimations by means of multiple linear regression models (R2 < 0.5). On the contrary, FDR needed only probe data to achieve R2 of 0.7, though root mean standard error (RMSE) was still 1.5 dS m−1. The extra measurements and calculations that modern electrical conductivity contact probes integrate, specifically, those based on FDR, remarkably increase their ability for soil salinity appraisal, although there is still room for improvement.

Electromagnetic Induction Techniques - Part 8

1998 ◽  
Author(s):  
PG Cook ◽  
BG Williams
Keyword(s):  
Electrical Conductivity ◽  
Case Studies ◽  
Electromagnetic Induction ◽  
Soil Profiles ◽  
Apparent Electrical Conductivity

Electromagnetic induction (EM) techniques are used in recharge/discharge studies by providing measurements of the apparent electrical conductivity of soil profiles. This booklet provides a summary of EM techniques that are most widely used. A number of case studies are presented which demonstrate the applications of the techniques to field problems.

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

1989 ◽  
Vol 69 (1) ◽  
pp. 25-32 ◽  
Author(s):  
R. C. McKENZIE ◽  
W. CHOMISTEK ◽  
N. F. CLARK
Keyword(s):  
Electrical Conductivity ◽  
Soil Moisture ◽  
Soil Temperature ◽  
Key Words ◽  
Soil Salinity ◽  
Electromagnetic Induction ◽  
Linear Equations ◽  
Temperature Correction ◽  
Available Soil Moisture ◽  
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

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