Geoscience Reference
In-Depth Information
Fig. 5.10
Textural soil classifi cation triangle used by soil scientists in the USA
fi ne-textured soils or vice versa? It is not a big point, but we know that dry sandy
soils are usually heavy not light and clayey soils, if dry, are light not heavy com-
pared to sandy soils. So as a result when someone talks about a heavy clay loam, it
is ambiguous. He may mean a loam with lots of sand or a loam with lots of clay. On
the other hand, because it takes more force to plow, break up, and turn over the
topsoil of a clay than do the same with a sand, clay soils are usually called heavy
soils and sandy soils are usually called light soils. Soils between light and heavy
soils are then named medium soils.
The textural classifi cation of soils was the fi rst attempt of soil scientists to
develop a useful jargon for identifying and naming soils on a regional basis. The
jargon became more objective as institutional cooperation in soil science was gradu-
ally established around the world. However, soil texture is nothing more than just
the fi rst prerequisite for further soil evolution. Since we like to use metaphors, soil
texture can be compared with the genes of animals. In other words, although soil
texture shows the limits of how and where a certain soil can be further developed,
the ultimate or slowly ever-changing characteristics and properties of a soil depend
upon the action of many other factors existing in the local climatic environment.
This was why we used the title “Soil's First Name” of this short chapter. The real
