Soil is a complex physical-biological system. It is the means of support and plant nutrition, it is the basis of agricultural production, the natural filter and the protective layer of underground water reserves, as well as the living space of a large amount of organisms. Contains granules of various sizes. Its mechanical properties depend on its texture and structure.The mechanical structure of the soil defined by the volume occupied by the solid components, organic and inorganic, and of the spaces containing gas and a dilute aqueous solution of inorganics, mainly salts.
The distribution in volume of these components is approximately:
• 45% inorganic solid components
• 5% organic solid components
• 50% gases and aqueous solution