scholarly journals Regional calibration and electromagnetic conductivity imaging for assessing the dynamics of soil salinity

2021 ◽  
Author(s):  
Maria Catarina Paz ◽  
Mohammad Farzamian ◽  
Ana Marta Paz ◽  
Nádia Luísa Castanheira ◽  
Maria Conceição Gonçalves ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Soil Salinity ◽  
Sea Water ◽  
Agricultural System ◽  
Soil Electrical Conductivity ◽  
Prediction Ability ◽  
Calibration Equation ◽  
Transient Nature ◽  
Salinity Levels ◽  
Conductivity Imaging

<p>Electromagnetic conductivity imaging (EMCI) is a state-of-the-art methodology for soil salinity assessment over large areas. It involves the following rationale: (1) use of the electromagnetic induction (EMI) geophysical technique to measure the soil apparent electrical conductivity (EC<sub>a</sub>, mS m<sup>−1</sup>) over an area; (2) inversion of EC<sub>a</sub> to obtain EMCI, which provides the spatial distribution of the soil electrical conductivity (σ, mS m<sup>−1</sup>); (3) calibration process consisting of a regression between σ and the electrical conductivity of the saturated soil paste extract (EC<sub>e</sub>, dS m<sup>−1</sup>), used as a proxy for soil salinity; and (4) conversion of EMCI into salinity maps using the obtained calibration equation.</p><p>In this study, we applied EMCI and a regional calibration in Lezíria Grande de Vila Franca de Xira, located in Portugal. The study area is an important agricultural system where soil faces the risk of salinization due to climate change, as the level and salinity of groundwater are likely to increase as a result of the rise of the sea water level and consequently of the estuary. These changes can also affect the salinity of the irrigation water which is collected upstream of the estuary.</p><p>EMI surveys and soil sampling were carried out between May 2017 and October 2018 at four locations with different salinity levels across the study area. A regional calibration was developed and its ability to predict EC<sub>e</sub> from EMCI was evaluated. The validation analysis showed that EC<sub>e</sub> was predicted with a root mean square error of 3.14 dS m<sup>−1</sup> in a range of 52.35 dS m<sup>−1</sup>, slightly overestimated (−1.23 dS m<sup>−1</sup>), with a strong Lin’s concordance correlation coefficient of 0.94 and high linearity between measured and predicted data (R<sup>2</sup> = 0.88). It was also observed that the prediction ability of the regional calibration is more influenced by spatial variability of data than temporal variability of data.</p><p>Because of the transient nature of data, it was also possible to perform a preliminary qualitative analysis of soil salinity dynamics in the study area, revealing salinity fluctuations related to the input of salts and water either through irrigation, precipitation, or level and salinity of groundwater.</p>

scholarly journals Assessing soil salinity dynamics using time-lapse electromagnetic conductivity imaging

SOIL ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 499-511
Author(s):  
Maria Catarina Paz ◽  
Mohammad Farzamian ◽  
Ana Marta Paz ◽  
Nádia Luísa Castanheira ◽  
Maria Conceição Gonçalves ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Cross Sections ◽  
Soil Salinity ◽  
Sea Water ◽  
Management Strategies ◽  
Time Lapse ◽  
Soil Salinization ◽  
Agricultural System ◽  
Prediction Ability ◽  
Conductivity Imaging

Abstract. Lezíria Grande de Vila Franca de Xira, located in Portugal, is an important agricultural system where soil faces the risk of salinization due to climate change, as the level and salinity of groundwater are likely to increase as a result of the rise of the sea water level and consequently of the estuary. These changes can also affect the salinity of the irrigation water which is collected upstream of the estuary. Soil salinity can be assessed over large areas by the following rationale: (1) use of electromagnetic induction (EMI) to measure the soil apparent electrical conductivity (ECa, mS m−1); (2) inversion of ECa to obtain electromagnetic conductivity imaging (EMCI) which provides the spatial distribution of the soil electrical conductivity (σ, mS m−1); (3) calibration process consisting of a regression between σ and the electrical conductivity of the saturated soil paste extract (ECe, dS m−1), used as a proxy for soil salinity; and (4) conversion of EMCI into salinity cross sections using the obtained calibration equation. In this study, EMI surveys and soil sampling were carried out between May 2017 and October 2018 at four locations with different salinity levels across the study area of Lezíria de Vila Franca. A previously developed regional calibration was used for predicting ECe from EMCI. Using time-lapse EMCI data, this study aims (1) to evaluate the ability of the regional calibration to predict soil salinity and (2) to perform a preliminary qualitative analysis of soil salinity dynamics in the study area. The validation analysis showed that ECe was predicted with a root mean square error (RMSE) of 3.14 dS m−1 in a range of 52.35 dS m−1, slightly overestimated (−1.23 dS m−1), with a strong Lin's concordance correlation coefficient (CCC) of 0.94 and high linearity between measured and predicted data (R2=0.88). It was also observed that the prediction ability of the regional calibration is more influenced by spatial variability of data than temporal variability of data. Soil salinity cross sections were generated for each date and location of data collection, revealing qualitative salinity fluctuations related to the input of salts and water either through irrigation, precipitation, or level and salinity of groundwater. Time-lapse EMCI is developing into a valid methodology for evaluating the risk of soil salinization, so it can further support the evaluation and adoption of proper agricultural management strategies, especially in irrigated areas, where continuous monitoring of soil salinity dynamics is required.

scholarly journals Monitoring soil salinity using time-lapse electromagnetic conductivity imaging

2020 ◽  
Author(s):  
Maria Catarina Paz ◽  
Mohammad Farzamian ◽  
Ana Marta Paz ◽  
Nádia Luísa Castanheira ◽  
Maria Conceição Gonçalves ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Soil Salinity ◽  
Management Strategies ◽  
Time Lapse ◽  
Soil Salinization ◽  
Spatiotemporal Variability ◽  
Coefficient Of Determination ◽  
Agricultural System ◽  
Soil Electrical Conductivity ◽  
Salinity Levels

Abstract. Lezíria Grande of Vila Franca de Xira, located in Portugal, is an important agricultural system where soil faces the risk of salinization, being thus prone to desertification and land abandonment. Soil salinity can be assessed over large areas by the following rationale: (1) use of electromagnetic induction (EMI) to measure the soil apparent electrical conductivity (ECa, dS m−1); (2) inversion of ECa to obtain electromagnetic conductivity images (EMCI) which provide the spatial distribution of the soil electrical conductivity (σ, mS m−1); (3) calibration process consisting of a regression between σ and the electrical conductivity of the saturated soil paste extract (ECe, dS m−1), used as a proxy for soil salinity; and (4) conversion of EMCI into salinity maps using the obtained calibration equation. In this study, EMI surveys and soil sampling were carried out between May 2017 and October 2018 at four locations with different salinity levels across the study area of Lezíria de Vila Franca. A previously developed regional calibration was used for predicting ECe from EMCI. This study aims to evaluate the potential of time-lapse EMCI and the regional calibration to predict the spatiotemporal variability of soil salinity in the study area. The results showed that ECe was satisfactorily predicted, with a root mean square error (RMSE) of 3.22 dS m−1 in a range of 52.35 dS m−1 and a coefficient of determination (R2) of 0.89. Results also showed strong concordance with a Lin’s concordance correlation coefficient (CCC) of 0.93, although, ECe was slightly overestimated with a mean error (ME) of −1.30 dS m−1. Soil salinity maps for each location revealed salinity fluctuations related to the input of salts and water either through irrigation, precipitation or groundwater level and salinity. Time-lapse EMCI has proven to be a valid methodology for evaluating the risk of soil salinization, and can further support the evaluation and adoption of proper agricultural management strategies, especially in irrigated areas, where continuous monitoring of soil salinity dynamics is required.

scholarly journals METODOLOGIA PARA AVALIAÇÃO DA SALINIDADE DO SOLO EM AMBIENTE PROTEGIDO

Irriga ◽  
2009 ◽  
Vol 14 (3) ◽  
pp. 383-397 ◽  
Author(s):  
Sergio Oliveira Pinto de Queiroz ◽  
Roberto Testezlaf ◽  
Edson Eiji Matsura
Keyword(s):  
Electrical Conductivity ◽  
Electric Conductivity ◽  
Soil Salinity ◽  
Vacuum Solution ◽  
Irrigation Management ◽  
Saline Soils ◽  
Soil Electrical Conductivity ◽  
Saturation Extract ◽  
Productive Process ◽  
Salinity Levels

METODOLOGIA PARA AVALIAÇÃO DA SALINIDADE DO SOLO EM AMBIENTE PROTEGIDO  Sérgio Oliveira Pinto de Queiroz1; Roberto Testezlaf2; Edson Eiji Matsura21Departamento de Tecnologia e Ciências Sociais, Universidade do Estado da Bahia, Juazeiro, BA,  [email protected]. 2Faculdade de Engenharia Agrícola, Universidade Estadual de Campinas, Campinas, SP  1 RESUMO Em condições de ambiente protegido a irrigação é essencial e a fertirrigação um agente facilitador do manejo da água e fertilização do solo; todavia, o uso contínuo e nem sempre adequado pode elevar a salinidade do solo, comprometendo o processo produtivo. Este trabalho objetivou avaliar uma metodologia para caracterizar a ocorrência de salinização em cultivos protegidos, usando diferentes métodos para determinação da condutividade elétrica do solo. Em laboratório foram avaliados os equipamentos Sensor Sigma Probe EC1, da Delta-T e extratores de solução do solo à vácuo. Os equipamentos foram utilizados em três solos com diferentes texturas e sob cinco níveis de salinidade: 0, 2, 4, 8 e 12 dS. m-1 a 25° C. Os resultados obtidos pelos métodos avaliados foram comparados ao método do extrato de saturação. O equipamento Sigma Probe EC1, por apresentar melhor correlação com o método de referência na fase laboratorial, foi utilizado nas visitas as propriedades, sob produção em ambiente protegido, na macrorregião de Campinas, revelou ser mais eficiente. A aplicação do questionário associada às leituras de condutividade elétrica do solo com o sensor Sigma Probe permitiu diagnosticar a deficiência no manejo da água e condutividade elétrica nas propriedades avaliadas. Os valores obtidos de condutividade elétrica no extrato de saturação do solo para as propriedades visitadas, não caracterizam solos salinos, mas podem afetar a produção de flores e outras plantas sensíveis à salinidade. UNITERMOS: manejo da irrigação; fertirrigação.  QUEIROZ, S. O. P. de.; TESTEZLAF, R.; MATSURA, E. E. METHODOLOGY FOR SOIL SALINITY EVALUATION IN GREENHOUSE  2 ABSTRACT Under controlled environmental conditions, irrigation is essential and the use of fertigation becomes a facilitator agent for water and fertilization management. However, the intensive use of fertigation in this type of productive process can increase soil salinity, and affect productive process. This work objective was to evaluate a methodology in order to characterize the salinization process occurrence of in greenhouse farms using different methods to determine soil electric conductivity l. Sigma Probe EC1, manufactured by Delta-T and vacuum solution manufactured extractors were evaluated under laboratory conditions. The equipment was used in three different soil textures, under five salinity levels: 0, 2, 4, 8 and 12 dS. m-1 at 25° C. The obtained results of electric conductivity were compared to the saturation extract method. The Sigma Probe EC1 equipment was used in farm visits, with controlled environmental production inCampinas macro region. Among the used equipment in the laboratorial part, the sigma Probe EC1 presented the best results for soil electrical conductivity determination, when compared to saturation extract, in saline and non saline soils. Using the questionnaire for electric conductivity determinations using Sigma Probe sensor it was possible to verify the deficiency in the soil moisture and electrical conductivity management. The obtained results for electric conductivity using the saturation extract methods do not characterize saline soils on the visited farms, but they showed that the salinity levels in the soil could affect flower production and other crops sensitive to salinity. KEYWORDS: irrigation management, fertigation.

scholarly journals Spatial and Temporal Variability of Soil Salinity in the Yangtze River Estuary Using Electromagnetic Induction

2021 ◽  
Vol 13 (10) ◽  
pp. 1875
Author(s):  
Wenping Xie ◽  
Jingsong Yang ◽  
Rongjiang Yao ◽  
Xiangping Wang
Keyword(s):  
Electrical Conductivity ◽  
Spatial Distribution ◽  
Soil Salinity ◽  
Yangtze River ◽  
Laboratory Data ◽  
River Estuary ◽  
Yangtze River Estuary ◽  
Soil Electrical Conductivity ◽  
The Yangtze River ◽  
The Yangtze River Estuary

Soil salt-water dynamics in the Yangtze River Estuary (YRE) is complex and soil salinity is an obstacle to regional agricultural production and the ecological environment in the YRE. Runoff into the sea is reduced during the impoundment period as the result of the water-storing process of the Three Gorges Reservoir (TGR) in the upper reaches of the Yangtze River, which causes serious seawater intrusion. Soil salinity is a problem due to shallow and saline groundwater under serious seawater intrusion in the YRE. In this research, we focused on the temporal variation and spatial distribution characteristics of soil salinity in the YRE using geostatistics combined with proximally sensed information obtained by an electromagnetic induction (EM) survey method in typical years under the impoundment of the TGR. The EM survey with proximal sensing method was applied to perform soil salinity survey in field in the Yangtze River Estuary, allowing quick determination and quantitative assessment of spatial and temporal variation of soil salinity from 2006 to 2017. We developed regional soil salinity survey and mapping by coupling limited laboratory data with proximal sensed data obtained from EM. We interpreted the soil electrical conductivity by constructing a linear model between the apparent electrical conductivity data measured by an EM 38 device and the soil electrical conductivity (EC) of soil samples measured in laboratory. Then, soil electrical conductivity was converted to soil salt content (soil salinity g kg−1) through established linear regression model based on the laboratory data of soil salinity and soil EC. Semivariograms of regional soil salinity in the survey years were fitted and ordinary kriging interpolation was applied in interpolation and mapping of regional soil salinity. The cross-validation results showed that the prediction results were acceptable. The soil salinity distribution under different survey years was presented and the area of salt affected soil was calculated using geostatistics method. The results of spatial distribution of soil salinity showed that soil salinity near the riverbanks and coastlines was higher than that of inland. The spatial distribution of groundwater depth and salinity revealed that shallow groundwater and high groundwater salinity influenced the spatial distribution characteristics of soil salinity. Under long-term impoundment of the Three Gorges Reservoir, the variation of soil salinity in different hydrological years was analyzed. Results showed that the area affected by soil salinity gradually increased in different hydrological year types under the impoundment of the TGR.

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.

Determining Soil Salinity from Soil Electrical Conductivity using Different Models and Estimates

1990 ◽  
Vol 54 (1) ◽  
pp. 46-54 ◽  
Author(s):  
J. D. Rhoades ◽  
P. J. Shouse ◽  
W. J. Alves ◽  
Nahid A. Manteghi ◽  
S. M. Lesch
Keyword(s):  
Electrical Conductivity ◽  
Soil Salinity ◽  
Soil Electrical Conductivity
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