Characteristics of the Environment - Field Sampling: Principles and Practices in Environmental Analysis - page 37

FIGURE 2.5 Textural triangle used by soil scientists to assign textural names
to soils of different textures.
textural name of a soil can be determined. A soil containing 10% sand, 15% clay, and
75% silt would have a silt loam texture. The term loam is used for textures for which the
sand, silt, and clay fractions contribute equally to the characteristics of the soil. The
percentage of clay is lower than silt or sand in loam because it has much higher activity
and so it takes less to have an equal effect. Table 2.1 gives the relationship between the
soil scientist's and the engineer's definition of soil particle size. If appropriate, a soil's
textural name may be prefixed by an indication of larger components. Thus, there might
be a gravely silt loam. This would indicate that the soil has a large percentage of gravel-
sized material in it. For the soil scientist the particles larger than 2.00 mm in diameter are
not as important as the sand, silt, and clay.
In addition to the above names there are other common, nonscientific, less specific
terms in common usage, such as light, heavy, clayey, and sandy. Heavy soils are high in