Abstract
Four undisturbed soil samples were collected differ in their textures representing Rashidiya, Mustah and Talseen 1&2 locations in Nineveh province / northern of Iraq, classified within great soil group Calciorthids. Samples were put in soil columns and leached by using distilled water (rain water), Tigris water, chlorine and sulfuric water to describe sodium leaching from calcareous soils via kinetic approaches. Results indicated that quantity of leached sodium up to 30th pore volumes of waters was ranged from 19.93 mmolc. liter-1 for sandy loam soil by using distilled water to 455.63 mmolc liter-1 for silty clay soil by using sulfuric water which reflect the role of water ionic strength in sodium leaching from soils. Leaching curves also referred that sodium was desorbed and leached via two stages. First rapid stage up to the 10th pore volumes indicating for of sodium salts solubility role, while second stage continued up to 30th pore volumes indicating for the role of ionic exchange. Mathematical description appeared a high harmony for 1st order equation in sodium leaching description and determination coefficient values R2 were ranged from (0.87 - 0.99), leaching rates were from (22× 10-3). Hr-1 for silty clay soil by using distilled water to (40 × 10-3). Hr-1 for sandy loam soil by using sulfuric water referring that sodium desorption and leaching to soil liquid phase was simple and spontaneous and leaching free energy ∆G values were ranged from -2.26 to -1.19 kjole. mole-1.
