Factors in Soil Formation
Factors in Soil Formation
1.
Climate: The two most important
climatic variables influencing soil formation are temperature and moisture.
·
Temperature has a direct influence on the weathering of bedrock to produce mineral particles. Rates of bedrock
weathering generally increase with higher temperatures. Temperature also
influences the activity of soil microorganisms, the frequency and magnitude of
soil chemical reactions, and the rate of plant growth.
·
Moisture levels in
most soils are primarily controlled by the addition of water via precipitation minus the losses due to evapotranspiration. High moisture availability in a soil promotes the
weathering of bedrock and sediments, chemical reactions, and plant growth. The
availability of moisture also has an influence on soil pH and the decomposition of organic matter.
2. Topography: This refers to the
landscape position and the slopes it has. Steep, long slopes mean water will
run down faster and potentially erode the surfaces of slopes. The effect will
be poor soils on the slopes, and richer deposits at the foot of the slopes.
Also, slopes may be exposed to more direct sunlight, which may dry out soil
moisture and render it less fertile. The steeper the surface slope, the
more likely any eroded material is to be transported out of the system.
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| Topographical Factor of Soil Formation |
3. Parent Material: Parent
Material refers to the rock and mineral materials from
which the soils develop. These materials can be derived from residual sediment
due to the weathering of bedrock or from sediment transported into an area by
way of the erosive forces of wind, water, or ice. Granites are more resistant
to weathering than gabbros. Sandstones are more resistant to weathering
than limestones in humid climates, but limestones are more resistant than
sandstones in arid climates.
4. Plant and Animal
activity: Plant and animal activity produces humic acids that are powerful
erosion agents. Plants can physically erode as well as chemically
erode. Plants stabilize soil profiles, Animals (including man) tend to
destabilize the soil profile, increasing erosion.
5. Time: Time influences
the temporal consequences of all of the factors described above . Reaction
rates are slow, the longer a rock unit has been exposed, the more likely it is
to be weathered.
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| Factors of Soil Formation |
