Estimation of saturated soil paste electrical conductivity, soluble cations and anions from different ratios of soil to water (1:1, 1:2.5, and 1:5) in non‐gypsiferous soils with various textures

Document Type : Research Paper

Authors

1 Department of Soil Science, Faculty of Agriculture, University of Tehran, Karaj, Iran

2 Agricultural Research, Education and Extension Organization (AREEO), Soil and Water Research Institute (SWRI), Karaj, Iran

Abstract

This research aims to determine and validate the relationship between the electrical conductivity (EC_e), cations and anions concentration in the extract of saturated soil paste and the relevant parameters in the extract of soil-to-water ratios namely 1:1, 1:2.5, and 1:5 in non‐gypsiferous soils with different textures. Accordingly, 64 soil samples from different regions of Iran were selected and EC, and cations and anions concentration in both saturated past extract and soil-to-water ratios extract were determined. Moreover, the soils were categorized into three texture classes: fine-, medium-, and coarse-textured. To develop and validate the overall relationships between EC_e and EC of different ratios, 43 soils were used for relationship development, and 21 soils were used for relationship validation. The results demonstrated that in the fine-textured soils, 〖 EC〗_e=2×EC_ (1:1) =4×EC_ (1:2.5) =8×EC_ (1:5); in the medium-textured soils, 〖 EC〗_e=2×EC_ (1:1) =5.5×EC_(1:2.5)=10×EC_(1:5); and in the coarse-textured soils, 〖 EC〗_e=2×EC_(1:1)=3×EC_(1:2.5)=6~8×EC_(1:5). Therefore, despite the limited number of soils, it can be recommended to use EC_ (1:1) for estimating 〖 EC〗_e since the regression relationship between these two methods remains constant and equal to two times of 〖 EC〗_e across three texture classes. Regardless of the soil texture, the following relationship was obtained for all studied soils; 〖 EC〗_e=2×EC_ (1:1) =5×EC_ (1:2.5) =10×EC_ (1:5). Also, the results of the validation of different relationships showed that the soil-to-water ratio of 1:1 due to lower errors, closer equation slope to 1:1 line and higher determination coefficient (R^2=0.99) gives a more accurate 〖 EC〗_e estimation compare to the other two ratios. Regarding the concentration of cations and anions, it can be recommended to use the 1:1 extract instead of saturated past extract, especially for non-saline soils, and provides a larger volume of extract.

Keywords

Main Subjects

EXTENDED ABSTRACT

 

Target:

This research aims to determine and validate the relationship between the electrical conductivity (EC_e), cations and anions concentration in the extract of saturated soil paste and the relevant parameters in the extract of soil-to-water ratios namely 1:1, 1:2.5, and 1:5 in non‐gypsiferous soils with fine, medium and coarse soil texture.

Research method:

In this study, a total of 300 soil samples were collected from various regions of Iran and analyzed regarding the general physiochemical properties including texture, electrical conductivity (EC), cation and anion concentrations in the saturated extract, and various soil-to-water ratios were measured. Based on the initial analysis, 64 non-gypsiferous samples with diverse physico-chemical properties were selected for further studies. The selected soils were classified into three texture categories: fine, medium, and course textured soils. To establish and validate the relationships between the ECₑ and EC at different ratios, we employed 64 samples for preliminary relationship development. Moreover, in another scenario, 43 samples were used for model development, and 21 samples were used for model validation. The relationships were assessed using statistical criteria including the coefficient of determination (R²), 1:1 line comparison, Root mean square error (RMSE), Mean absolute error (MAE), and Relative error percentage (%RE).

Findings:

In general, the slope of the regression equations increased with increasing the degree of dilution. The results demonstrated that in the fine-textured soils, EC_e=2×EC_(1:1)=4×EC_(1:2.5)=8×EC_(1:5). In the medium-textured soils, EC_e=2×EC_(1:1)=5.5×EC_(1:2.5)=10×EC_(1:5). In the coarse-textured soils, EC_e=2×EC_(1:1)=3×EC_(1:2.5)=6~8×EC_(1:5). Therefore, despite the limited number of soil samples, it is recommended to use the EC_(1:1) for estimating EC_e, since the regression relationship between these two methods remains constant and equal to two times of EC_(1:1) across all three soil texture classes. The results of developing relationships using 64 and 43 samples demonstrated that 〖EC〗_e=2×〖EC〗_(1:1)=5×〖EC〗_(1:2.5)=10×〖EC〗_(1:5). Also, the results of the validation of different relationships showed that the soil-to-water ratio of 1:1 due to the lower RMSE, lower MAE and lower RE, closer equation slope to 1:1 line, and higher determination coefficient (R^2=0.99) provides a more accurate estimate of EC_e compared to the other ratios. Therefore, EC_e can be estimated with acceptable accuracy by multiplying EC_(1:1) by two. In the case of cations and anions, similar relationships were observed between EC_e and EC of different soil-to-water ratios. The slope of the regression equations increased with the degree of dilution. The validation results for different relationships in all ions (cations and anions) showed that the soil-to-water ratio of 1:1 due to lower errors, closer equation slope to 1:1 line and higher R^2 that provides a more accurate estimate compared to other ratios. Regarding the concentration estimation of cations and anions, it is recommended to use the 1:1 soil-to-water ratio with a larger volume of extract (more than 10 ml) than saturated past extract, especially for non-saline soils

Conclusion:

Electrical conductivity (EC) is one of the important parameters for evaluating soil salinity for various purposes, including agriculture. Therefore, continuous monitoring of soil salinity using simple and affordable methods is necessary. This parameter is typically determined and reported in saturated paste extract as a standard method. However, due to various problems in preparing saturated paste, including time and cost, it can be difficult and cumbersome. Different researchers have tried to estimate soil EC using different ratios of soil to water. One of the factors affecting the estimation of EC_e using different ratios of soil to water is the presence of soluble salts, especially gypsum which buffers the calcium and sulfate ions in the solution. The results showed that EC_e of non-gypsiferous soils with different textures can be estimated by doubling the EC_(1:1) with acceptable accuracy, saving time and cost. The greater the dilution, the greater the deviation of the ionic ratios of the sample solution compared to the soil solution in field conditions. Moreover, the uncertainty in the estimations increased with increasing the soil-to-water ratio.

Author Contributions

Ayoub Avizhgan: Design, Analysis, and Interpretation of data Writing- Original draft preparation, Visualization. Karim Shahbazi: Conceptualization, Methodology, Design, Revision of the manuscript and Editing. Mostafa Marzi: Design, Revision of the manuscript and Editing. Arzhang Fathi-Gerdelidani: Revision of the manuscript and Editing.

Data Availability Statement

Data can be sent from the corresponding author by email upon request.

Acknowledgements

We are grateful to the Soil and Water Research Institute of Karaj for financial support.

Ethical considerations

The authors avoided data fabrication, falsification, plagiarism, and misconduct.

Conflict of interest

The author declares no conflict of interest.

References

Aboukila, E., & Abdelaty, E. (2017). Assessment of saturated soil paste salinity from 1: 2.5 and 1: 5 soil-water extracts for coarse textured soils. Alexandria Science Exchange Journal, 38(October-December), 722-732.
Biswas, A., & Biswas, A. (2014). Comprehensive approaches in rehabilitating salt affected soils: a review on Indian perspective. Open transactions on geosciences, 1(1), 13-24.
Corwin, D. L., & Yemoto, K. (2017). Salinity: Electrical conductivity and total dissolved solids. Methods of soil analysis, 2(1).
Etemadi, H., Goli, E., & Shahabi, M. (2018). Relationship between electrical conductivity of saturation past extract and different soil:water ratios. The 13th National Conference on Watershed Management Science & Engineering of Iran and The 3rd National Conference on Conservation of Natural Resources and Environment, Ardebil, Iran, (in Persian).
Farahmand, A., Oustan, S., Jafarzadeh, A., & Aliasgharzad, N. (2012). Salinity and Sodicity Parameters in Some Salt-Effected Soils of Tabriz Plain. Water and Soil Science, 22(1), 1-15 (in Persian).
Franzen, D. (2003). Managing saline soils in North Dakota.
Gee, G. W., & Or, D. (2002). 2.4 Particle-size analysis. Methods of soil analysis. Part, 4(598), 255-293.
Gharaibeh, M. A., Albalasmeh, A. A., & El Hanandeh, A. (2021). Estimation of saturated paste electrical conductivity using three modelling approaches: Traditional dilution extracts; saturation percentage and artificial neural networks. Catena, 200, 105141.
Hammam, A., & Mohamed, E. (2020). Mapping soil salinity in the East Nile Delta using several methodological approaches of salinity assessment. The Egyptian Journal of Remote Sensing and Space Science, 23(2), 125-131.
He, Y., DeSutter, T., Hopkins, D., Jia, X., & Wysocki, D. A. (2013). Predicting ECe of the saturated paste extract from value of EC1: 5. Canadian Journal of Soil Science, 93(5), 585-594.
He, Y., DeSutter, T., Prunty, L., Hopkins, D., Jia, X., & Wysocki, D. A. (2012). Evaluation of 1: 5 soil to water extract electrical conductivity methods. Geoderma, 185, 12-17.
Hogg, T., & Henry, J. (1984). Comparison of 1: 1 and 1: 2 suspensions and extracts with the saturation extract in estimating salinity in Saskatchewan soils. Canadian Journal of Soil Science, 64(4), 699-704.
Hopmans, J. W., Qureshi, A., Kisekka, I., Munns, R., Grattan, S., Rengasamy, P., . . . Minhas, P. (2021). Critical knowledge gaps and research priorities in global soil salinity. Advances in agronomy, 169, 1-191.
Hossain, M. S., Rahman, G. M., Solaiman, A., Alam, M. S., Rahman, M. M., & Mia, M. B. (2020). Estimating electrical conductivity for soil salinity monitoring using various soil-water ratios depending on soil texture. Communications in Soil Science and Plant Analysis, 51(5), 635-644.
Isdory, D., Massawe, B., & Msanya, B. (2021). Predicting soil ECe based on values of EC1: 2.5 as an indicator of soil salinity at Magozi Irrigation Scheme, Iringa, Tanzania. Tanzania Journal of Agricultural Sciences, 20(1), 63-71.
Kargas, G., Chatzigiakoumis, I., Kollias, A., Spiliotis, D., & Kerkides, P. (2018a). An Investigation of the relationship between the electrical conductivity of the soil saturated paste extract ECe with the respective values of the mass soil/water ratios 1: 1 and 1: 5 (EC1: 1 and EC1: 5). Paper presented at the Multidisciplinary Digital Publishing Institute Proceedings.
Kargas, G., Chatzigiakoumis, I., Kollias, A., Spiliotis, D., & Kerkides, P. (2018b). An Investigation of the relationship between the electrical conductivity of the soil saturated paste extract ECe with the respective values of the mass soil/water ratios 1: 1 and 1: 5 (EC1: 1 and EC1: 5). Paper presented at the Proceedings.
Kargas, G., Londra, P., & Sgoubopoulou, A. (2020). Comparison of soil EC values from methods based on 1: 1 and 1: 5 soil to water ratios and ECe from saturated paste extract based method. Water, 12(4), 1010.
Kargas, G., Londra, P. A., Koka, D., & Sgoubopoulou, A. (2023). Relationships between saturated paste and 1: 1 or 1: 5 soil/water extract sodium adsorption ratios. Irrigation and Drainage, 72(2), 503-514.
Khorsandi, F., & Yazdi, F. A. (2007). Gypsum and texture effects on the estimation of saturated paste electrical conductivity by two extraction methods. Communications in Soil Science and Plant Analysis, 38(7-8), 1105-1117.
Khorsandi, F., & Yazdi, F. A. (2011). Estimation of saturated paste extracts’ electrical conductivity from 1: 5 soil/water suspension and gypsum. Communications in Soil Science and Plant Analysis, 42(3), 315-321.
Lesch, S. M., Strauss, D. J., & Rhoades, J. D. (1995). Spatial prediction of soil salinity using electromagnetic induction techniques: 1. Statistical prediction models: A comparison of multiple linear regression and cokriging. Water Resources Research, 31(2), 373-386.
Libutti, A., Cammerino, A. R. B., & Monteleone, M. (2018). Risk assessment of soil salinization due to tomato cultivation in mediterranean climate conditions. Water, 10(11), 1503.
Loeppert, R. H., & Suarez, D. L. (1996). Carbonate and gypsum. Methods of soil analysis: Part 3 Chemical methods, 5, 437-474.
Marzi, M., Shahbazi, K., Esmaeilzadeh, L., & Beheshti, M. (2022a). The effect of contact time, extractant type, and soil/extractant ratio on gypsum determination by Acetone method. Iranian Journal of Soil and Water Research, 53(4), 701-713. doi:10.22059/ijswr.2022.332920.669111
Marzi, M., Shahbazi, K., Esmaeilzadeh, L., & Beheshti, M. (2022b). The effect of contact time, extractant type, and soil/extractant ratio on gypsum determination by Acetone method. Iranian Journal of Soil and Water Research, 53(4), 701-713 (In Persian).
Matthees, H. L., He, Y., Owen, R. K., Hopkins, D., Deutsch, B., Lee, J., . . . DeSutter, T. M. (2017). Predicting soil electrical conductivity of the saturation extract from a 1: 1 soil to water ratio. Communications in Soil Science and Plant Analysis, 48(18), 2148-2154.
Mirzaee, S., Ghorbani-Dashtaki, S., & Kerry, R. (2020). Comparison of a spatial, spatial and hybrid methods for predicting inter-rill and rill soil sensitivity to erosion at the field scale. Catena, 188, 104439.
Momeni, A. (2011). Geographical Distribution and Salinity Levels of Soils Resources of Iran. Iranian Jornal of Soil Research, 24(3), 203-215 doi:10.22092/IJSR.2011.126633 (in Persian)
Ozcan, H., Ekinci, H., Yigini, Y., & Yuksel, O. (2006). Comparison of four soil salinity extraction methods. Paper presented at the Proceedings of 18th International Soil Meeting of" Soil Sustaining Life on Earth, Managing Soil and Technology.
Pittman, J., Kress, M., & Zhang, H. (2001). Comparison of two soil salinity extraction methods. Paper presented at the Proceedings of the 8th international petroleum environment conference, Houston, Texas.
Rayment, G., & Lyons, D. (2011). Soil Chemical Analysis Methods-Australia. In: CSIRO Publishing: Collingwood, Australia.
Rhoades, J., Manteghi, N. A., Shouse, P., & Alves, W. (1989). Estimating soil salinity from saturated soil‐paste electrical conductivity. Soil Science Society of America Journal, 53(2), 428-433.
Richards, L. A. (1954). Diagnosis and improvement of saline and alkali soils (Vol. 78): LWW.
Seo, B.-S., Jeong, Y.-J., Lee, K.-S., & Choi, W.-J. (2021). Effects of equilibrium time on electrical conductivity measurements using soil-water extracts and soil saturated paste. Korean Journal of Soil Science and Fertilizer, 54(2), 257-263.
Shahbazi, K., Marzi, M., Mohammadi, M. H., Asadi, H., Fathi-Gerdelidani, A., Hasheminasab Zavareh, K. S., . . . Cheraghi, M. (2024). Methods of Soil Analysis: Sampling, Chemical and Physical Methods. First edition. Karaj. Soil and Water Research Institute (in Persian).
Shaw, R. (1994). Estimation of electrical conductivity of saturation extracts from the electrical conductivity of 1: 5 soil: water suspensions and various soil properties (No. Project report QO94025). Department of Primary Industries, Queensland.
Singh, A. (2018). Alternative management options for irrigation-induced salinization and waterlogging under different climatic conditions. Ecological Indicators, 90, 184-192.
Singh, A. (2022). Soil salinity: A global threat to sustainable development. Soil Use and Management, 38(1), 39-67.
Slavich, P., & Petterson, G. (1993). Estimating the electrical conductivity of saturated paste extracts from 1: 5 soil, water suspensions and texture. Soil Research, 31(1), 73-81.
Sonmez, S., Buyuktas, D., Okturen, F., & Citak, S. (2008). Assessment of different soil to water ratios (1: 1, 1: 2.5, 1: 5) in soil salinity studies. Geoderma, 144(1-2), 361-369.
Sultan, K. (2006). Clay mineralogy of central Victorian (Creswick) soils: clay mineral contents as a possible tool of environmental indicator. Soil and Sediment Contamination: An International Journal, 15(4), 339-356.
Tian, F., Hou, M., Qiu, Y., Zhang, T., & Yuan, Y. (2020). Salinity stress effects on transpiration and plant growth under different salinity soil levels based on thermal infrared remote (TIR) technique. Geoderma, 357, 113961.
Visconti, F., de Paz, J. M., & Rubio, J. L. (2010). What information does the electrical conductivity of soil water extracts of 1 to 5 ratio (w/v) provide for soil salinity assessment of agricultural irrigated lands? Geoderma, 154(3-4), 387-397.
Walkley, A., & Black, I. A. (1934). An examination of the Degtjareff method for determining soil organic matter, and a proposed modification of the chromic acid titration method. Soil Science, 37(1), 29-38.
Wang, Y., Wang, Z.-x., LIAN, X.-j., XIAO, H., WANG, L.-y., & HE, H.-d. (2011). Measurement of soil electric conductivity and relationship between soluble salt content and electrical conductivity in Tianjin coastal area. Tianjin Agricultural Sciences, 2(8).
Zhang, H., Schroder, J., Pittman, J., Wang, J., & Payton, M. (2005). Soil salinity using saturated paste and 1: 1 soil to water extracts. Soil Science Society of America Journal, 69(4), 1146-1151.
Iranian Journal of Soil and Water Research
Volume 56, Issue 1
April 2025
Pages 247-263

Files

Share

How to cite

Statistics