Environmental Engineering Reference
In-Depth Information
Hot
Latosols
oxisols
and
inceptisols
Reddish-
brown
Reddish-
chestnut
Reddish-
prairie
Red desert
Ultisols
red-yellow podzolic
and
reddish-brown lateritic
Alfisols
Mollisols
Aridisols
Brown
desert
Alfisols
and
inceptisols
gray-brown podzolic
and
brown podzolic
Mollisols
Gray
desert
Chestnut
Chernozem
Brunizem
Spodosols
podzol
Alfisols
gray wooded
Cold
Tundra
Inceptisols
Tundra
Dry
Increasing mean annual precipitation
Wet
FIGURE 7.115
Diagram showing the relationship of the Great Soil Groups of the World and the classification terminology of
the Seventh Approximation. (From Zumberberg, J. H. and Nelson, C. A.,
Elements of Geology
, Wiley, New York,
1972. Reprinted with permission of John Wiley & Sons, Inc.)
7.8.3
Plant Indicators
Significance
There is a strong relationship between subsurface conditions and vegetation because the
various species of plants that inhabit a particular location differ in their requirements for
water and nutrients. A general relationship between climate, vegetation, and shallow sub-
surface conditions is given in
Figure 7.116.
Some Indicators
•
Trees growing in a line may be indicative of seepage along a terrace edge, or a
fault zone in an arid or semiarid climate.
•
Orchards are typically found in well-drained areas.
•
Willows and hemlocks require substantial amounts of moisture.
•
Poplars and scrub oaks are found in areas of low moisture (sandy soils above the
water table in a moist climate).
•
Banana trees prefer colluvial soils to residual soils on slopes in tropical climates.
•
Thin vegetative cover in moist climates indicates either a free-draining soil or a
rock formation with little or no soil cover, a deep water table that can occur in
sands, “porous clays,” or weathered foliated rocks.
Some Geographic Relationships
•
In the Rocky Mountains, stands of aspen seem to favor damp ground underlain
by colluvium with much organic matter.
•
In New Jersey, good farms and forests grow in the coastal plain region where the
Cretaceous clays containing the potassium-rich glaconite outcrop, whereas only
scrub oak and pines grow in neighboring sandy soils.
