Vertical section of horizon sequence is called soil profile. It starts from the uppermost horizon extends to parent material.
Definition of Soil Profile
A soil profile is a vertical section of the soil that depicts the various layers or horizons of the soil from the surface down to the parent material.
Vertical section of horizon sequence is called soil profile.
Horizon is a layer of soil parallel to upper surface and have different characteristic feature above and below it.
It starts from the uppermost horizon extends to parent material.
It is record of soil forming process.
Soil profile give the clear picture of soil.
Layers of Soil Profile :-
Soil profile Consists of 5 layers or horizon -
O = Organic Horizon of soil profile -
It is horizon lies above the minerals soil or M horizon.
Forms by the litter of dead plants and animals.
Occurs generally in forested soil not in grassland soils.
Forests has higher amount of organic matter due its rich plants parts and other faunal residue.
M = Mineral Horizon -
Top most mineral horizon.
Mixture of decomposed (humified) organic matter,
Gives darker color than that of the lower horizons.
E = Eluvial Horizon
It is a horizon of Eluviation.
Clay and sesquioxides are invariably leached out,
leaving a concentration of resistant minerals such as quartz.
Generally lighter in color,
Available below the ‘M’ horizon.
I = Illuvial Horizon -
Zone of Illuviation.
Eluviated materials form the above layers illuviated in this layer.
In humid regions, materials such as sesquioxides and silicate clays deposited in abundance.
In arid and semi-arid regions CaCO3, CaSO4 and other salts may accumulate in it.
P = Horizon -
It is the unconsolidated material underlying the ‘Solum’ (A & B).
Partially weathered parent material.
It may or may not be the same as the parent material from which the solum formed. The ‘P’ horizon is out side the zones of major biological activities and is generally little affected by the processes that formed the horizons above it
R= Rock Horizon -
Underlying consolidated rock, with little evidence of weathering or unweathered parent material or rocks.
Difference between surface soil and sub-surface soil -
UPSC Agriculture Optional Previous Year Question Soil profile. 2005 |
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