Downward percolating water also causes the translocation of nutrients and complex chemical substances within the soil profile. Like the finest particles, these dissolved substances are removed from the surface layer and are either removed by groundwater outflow or deposited at a lower level in the soil. The complete chemical removal of these substances from the soil profile is known as leaching . The texture of a soil refers to the size distribution of the mineral particles composing the soil. Table 11d-1 describes the classification of soil particles according to size.
Particle size ranges for sand, silt, and clay.
Despite their small size, clay particles have a very large surface area relative to their volume. This large surface is highly reactive and has the ability to attract and hold positively charged nutrient ions. These nutrients are available to plant roots for nutrition. Clay particles are also somewhat flexible and plastic because of their lattice-like design. This feature allows clay particles to absorb water and other substances into their structure.