web soil survey

Soil Texture

The texture of a soil refers to the size distribution of the mineral particles found in a representative sample of soil. Particles are normally grouped into three main classes: sand, silt, and clay. Table 1 describes the classification of soil particles according to size.
Table 1: Particle size ranges for sand, silt, and clay.
Type of Mineral Particle Size Range
Sand 2.0 - 0.06 millimeters
Silt 0.06 - 0.002 millimeters
Clay less than 0.002 millimeters

Clay is probably the most important type of mineral particle found in a soil. 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.