Modeling soil salinity using conductometry

Soil salinity is one of the key issues contributing to land degradation, particularly in arid and irrigated regions of Central Asia and southern Kazakhstan. This study explores the applicability of the conductometric method as a rapid tool for assessing soil salinity levels based on electrical conductivity (EC) measurements of a water extract. The research focused on sierozem soils from the Shaulder massif in the Turkistan region, which are characterized by varying degrees of salt accumulation. A total of 76 soil samples were collected from depths up to 1 meter, and water extracts were prepared in a 1:5 soil-to-water ratio. Measurements were carried out using a calibrated FieldScout Direct Soil EC Meter (CTS 50C). Based on the obtained data, soil salinity classification was performed according to the international standards by Richards (1954) and FAO. EC values ranged from 0.254 to 15.420 mS/cm, covering the spectrum from non-saline to highly saline soils. Five types of regression models were developed and compared: linear, logarithmic, power, second-degree polynomial, and third-degree polynomial. The third-degree polynomial model demonstrated the highest accuracy (R² = 0.947; MSE = 0.034). ANOVA confirmed the statistical significance of the influence of EC on salt content (p < 0.001). The resulting models can be applied for rapid salinity diagnostics, soil zoning, and reclamation planning.

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