Predicting Soil Electrical Conductivity of Saturated Paste Extract Using Pedotransfer Functions in Northeastern Tunisia

Abstract

Soil electrical conductivity is a key indicator of soil salinity and sustainability, particularly in arid and semi-arid regions. Accurate estimation of EC is essential for managing soil salinity and ensuring crop productivity. Five pedotransfer functions (PTFs) were developed and evaluated for predicting electrical conductivity in a saturated paste extract using soil parameters, such as particle size analysis, pH, organic carbon, total nitrogen, cation exchange capacity, and electrical conductivity in a 1:5 soil-to-water extract, in agricultural soils of northern Tunisia. The accuracy of each PTF was systematically evaluated. PTF1 represented an R2 value of 0.85, PTF2 showed an R2 of 0.71 for the stepwise regression model, PTF3 achieved an R2 of 0.84, PTF4, based on Lasso/Ridge regression, reached an R2 of 0.89, and PTF5 reached an R2 of 0.83. Our findings revealed regional variations in soil salinity, with certain areas showing elevated salinity levels that could affect agricultural sustainability. This research emphasizes the importance of developing ad hoc PTFs as a reliable tool for predicting soil salinity and, consequently, assuring sustainable soil management in northeastern Tunisia.