Soil Solution a solution is a liquid made up of a mixture of several substances, of which one, generally more abundant, is called the solvent, and the others, the dissolved substances. In the soil, the solvent is water and the substances dissolved are ions, most of which are found in plant ash. The soil solution can be collected in the laboratory by slow watering or in the field by drainage of lysimeters. It constantly varies with climate and biological phenomena. A permanent exchange exists between the ions retained by the adsorption complex and the ions existing in the soil solution. Soil solution is in general concentrated in arid and semiarid regions due to low rainfall. As a sub-humid sub-tropical country, the concentration of soil solution in Bangladesh is generally low. [Sirajul Hoque]