Geoscience Reference
In-Depth Information
Global distribution of Entisols
(a)
(b)
Figure 11.33 Entisols.
(a) Generalized map of Entisols on
Earth. These soils occur on about 16% of Earth's ice-free land
area. (
Source:
U.S. Department of Agriculture.) (b) An Entisol
in southern Idaho. Note the very thin, if existent, A horizon in
this soil. (c) An Entisol landscape in Michigan. The vegetation
is growing on a recent deposit of windblown sand along Lake
Michigan.
(c)
easily yield nutrients through weathering; or (3) the parent
material has recently been transported, resulting in little time
for a soil to develop (Figure 11.33c). Given that this range of
soil-forming factors can occur just about anywhere, Entisols
appear at all latitudes.
a step in formation above Entisols, which have limited ho-
rizon development. The primary soil-forming factor associ-
ated with Inceptisols is time. On the one hand, these soils are
better developed than Entisols because they have had more
time to develop. Thus, Inceptisols may have a weak E hori-
zon (Figure 11.34c). On the other hand, insufficient time has
elapsed for the soil to develop horizons that meet the specific
criteria of a better-developed soil order such as Mollisols,
Spodosols, or Ultisols. Another important soil-forming fac-
tor associated with Inceptisols is parent material because
most of these soils form in sediments that have been recently
transported, but not so recently that the soil shows no sign
of development. As in the case of Entisols, the soil-forming
factors that contribute to the formation of Inceptisols can oc-
cur just about anywhere.
Inceptisols
Inceptisols
are soils with weakly developed
horizons. These soils are found on about 10% of Earth's
ice-free land area (Figure 11.34a), and can occur just about
anywhere, even in places like the Appalachian Mountains
(Figure 11.34b). It is useful to think of Inceptisols as being
Inceptisols
Soils that have one or more weakly developed
horizons due to some alteration and removal of soluble minerals.
