Fundamental Soil forming Processes:

a. Humification:

• It is the process of transformation of raw organic matter into humus. It is extremely a complex process involving various organisms.
• Simple compounds.> sugars and starches.> proteins-> cellulose – >tannins-> dark coloured substance, known as humus, is formed.

b. Eluviation:

• It is the mobilization and iranslocation of certain constituent’s viz. Clay, Sesquioxides, Si02, humus, CaCO3 , other salts etc. from one point of soil body to another.
• Eluviation means washing out. It is the process of removal of constituents in suspension or solution by the percolating water from the upper to lower layers.
• The horizon formed by the process of eluviation is termed as eluvial horizon (A2 or E horizon).
• Translocation depends upon relative mobility of elements and depth of percolation.

c. Illuviation:

• The horizons formed by this process are termed as illuvial horizons (B-horizons, especially Bt)
• The process leads to textural contrast between E and Bt horizons, and higher fine: total clay ratio in the Bt horizon.

d. Horizonation:

• It is the process of differentiation of soil in different horizons along the depth of the soil body.
• The differentiation is due to the fundamental processes, humification, eluviation and illuviation.