17. Parent Material
Parent material is the material from which the soil has formed. These deposits range in character from
organic peat to unconsolidated rock. Parent material can either form in place or be transported from
elsewhere. Residual, or parent materials formed in place,
include weathered igneous, sedimentary,
and metamorphic rocks. Transported parent materials are moved by wind, water, ice, or gravity.
Wind transported materials include ash, loess, and sand.
5
5
Water transported
materials include alluvial, lacustrine, marine, and beach deposits. Ice transported
materials, either directly by ice or by melt waters from the ice, all come under the heading glacial
drift. There is a detailed nomenclature for this large group of deposits, but their enumeration is not
warranted here. Gravity transported materials come under the heading of colluvium.
19. Erosion
The degree to which accelerated erosion, or that induced by man, has affected soil formation and
suitability for management is evaluated in a site description.
If possible, the properties of both the eroded and uneroded phase of a
particular soil should be
evaluated.
The effect of erosion can then be determined by a comparison. Soils are divided into erosion classes
based on the amount of material lost from the soil surface.
20. Soil Depth
Soil depth is determined by the total thickness of soil horizons that are significant to soil use and
management.
It is normally the depth to which plant roots develop. Soil depth
is described as either deep, moderate,
shallow, or very shallow to a restrictive layer.
Restrictive layers include cemented horizons, claypans, bedrock, and sometimes abrupt textural
changes.
21. Conclusion:
Soil morphology, characterized by soil structural analysis in topo
sequences, facilitates the
understanding of the topographic influence on the chemical, physical,
hydrological and
micromorphological attributes of soils. Micromorphology combined with other soil analyses helps in
the integration and synthesis of soil processes, covering several hierarchical levels , from the
landscape to the soil microstructure .
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