Soil Shrinkage Characteristics as Affected by Solution Composition and Mineral Contents

Abstract

ABSTRACTSoil-shrinkage characteristics affect fluid transport and soil mechanical properties, with broad implications for environmental flows, crop production, and civil engineering designs. We quantified mild-saline-solutions effects on soil shrinkage curves and developed pedotransfer functions to predict curve parameters. Seven soil and soil mixes were equilibrated with solutions of 0.5-to-8 dS m−1 and 0-to-20 sodium adsorption ratios (SAR). Saturated paste rods were dried; water contents and isotropic shrinkage measured. Texture affected shape-forming factors when clay and smectite contents were >260 and 140 g kg−1, respectively. Solutions ≥2 dS m−1 affected the coefficient of linear extensibility for smectitic soils containing clay ≥300 g kg−1. Solution SAR affected only the highest clay content (530 g kg−1) and mixed mineralogy soils. However, the solution salinity levels were not high enough to affect shape factors of the shrinkage curves. Pedotransfer functions successfully described soil shrinkage with root-mean-squared-errors 1 to 4 magnitudes lower than the highest measured values.