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

Articles in Press

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 saturated soil paste extract electrical conductivity ECe, and cation and anion concentration and those of different soil-to-water ratios of 1:1, 1:2.5, and 1:5 in non‐gypsiferous soils with different textures. 64 soil samples from different regions of Iran were selected and their texture, and EC and concentration of cations and anions of the saturated past extract, and different soil-to-water ratios were measured. The soils were categorized into three texture classes: fine-, medium-, and coarse-textured. To develop and validate the overall relationships between ECe 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, ECe=2EC1:1=4 EC1:2.5=8EC1:5; in the medium-textured soils, ECe=2EC1:1=5.5EC1:2.5=10EC1:5; and in the coarse-textured soils, ECe=2EC1:1=3EC1:2.5=6-8EC1:5. Therefore, despite the limited number of soil samples, it is recommended to use EC1:1for estimating ECe since the regression relationship between these two methods remains constant and equal to two across three texture classes. The following relationship was obtained for all studied soils ECe=2EC1:1=5EC1:2.5=10EC1:5. 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 (R2=0.99) gives a more accurate ECe estimate compared to the other two ratios. Regarding the concentration estimation of cations and anions, it is recommended to use 1:1 soil-to-water ratio with a larger volume of extract than saturated past extract, especially for non-saline soils.

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Iranian Journal of Soil and Water Research

Articles in Press, Accepted Manuscript
Available Online from 01 December 2024

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