Managing salt affected soils: Issues and strategies

Abstract

Improper land and water management has amplified the degradation of soil across the world. In saline soil, high concentration of soluble salts results in high soil permeability, thus, making soil physical conditions favorable for leaching. But the presence of excess Na+ ions as in the sodic soil, makes the reclamation process more complex because of the poor hydraulic conductivity and infiltration rate. The problem in the sodic soil is for the swelled electric double layer on the clay surface. More monovalent ions are required to balance the fixed deficit charges on the clay surface than the multivalent ions. Hence, the thickness of electric double layer in sodic soil is more than the non-sodic soil where multivalent ions are dominant. Most of the previous studies on reclamation of salt affected soils are field studies. A few analytical models were attempted without involving the interaction of ions and geometry of soil, hence failed. The electric double layer has hardly been taken into account for solving the reclamation problem of the sodic soil. As Na+ and Ca2+ ions are ions of concern for reclamation of the sodic soil, the interactions among these ions need to be considered through the electric double layer theory.