Specific Soil Forming Processes

a. Calcification: precipitation and accumulation of calcium carbonate (CaCO3). Calcic horizon

b. Decalcification: It is the reverse of calcification that is the process of removal of CaCO3 or calcium ions from the soil by leaching.

c. Podzolization:

• Refers to formation of Podzols and Podzolic soils. The calcification process tends to concentrate calcium in the lower part of the B horizon, whereas podzolization leaches the entire solum of calcium carbonates.
• Apart from calcium, the other bases are also removed and the whole soil becomes distinctly acidic. In fact, the process is essentially one of acid leaching.
• The Russians used the term Podzols (pod means under, the zola means ash like i.e. ash-like horizon appearing beneath the surface horizon) for such soils.

d. SoloclizatIon or dealkallzation:

• The process refers to the removal of Na + from the exchange sites. This process involves dispersion of clay. Dispersion occurs when Na + ions become hydrated
• The Podzolization is a soil forming process which prevails in a cold and humid climate where coniferous and acid forming vegetations dominate. The humus and Sesquioxide become mobile and leached out from the upper horizons and deposited in the lower horizon.
• Removal of Fe and Al

e. Laterization: the word later meaning brick or tile cemented horizon when dried (in tropics)

• Massively impregnated with sesquioxides (iron and aluminium oxides) to extent of 70 to 80 per cent of the total mass, are called laterites or latosols (Oxisols).
• Removes silica, instead of sesquioxides from the upper layers and thereby leaving sesquioxides to concentrate in the solum.

f. Gleization:

• The term glei is of Russian origin means blue, grey or green clay. The Gleization is a process of soil formation resulting in the development of a glei (or gley horizon) in the lower part of the soil profile above the parent material due to poor drainage condition (lack of oxygen) and where waterlogged conditions prevail. Such soils are called hydromorphic soils.
• The reduction of iron under anaerobic (waterlogged) conditions with production of bluish to greenish grey colour with or without mottles or ferro-manganese concretion.

g. Salinization:

• It is the process of accumulation of soluble salts, such as sulphates and chlorides of calcium, magnesium, sodium and potassium, in soils in the form of a salty (salic) horizon.
• It is quite common in arid and semi arid regions.

h. Desalinization:

• It is the process of removal by leaching of excess soluble salts from horizons or soil profile.

i. Solonization or Alkalization:

• The process involves the accumulation of sodium ions on the exchange complex of the clay, resulting in the formation of sodic soils (Solonetz).

j. Pedoturbation:

• It is the process of mixing of the soil.

Types of pedoturbation are:

• Faunal pedoturbation: It is the mixing of soil by animals such as ants, earthworms, moles, rodents, and man himself
• Floral pedoturbation : It is the mixing of soil by plants as in tree tipping that forms pits and mounds
• Argillic pedoturbation: It is the mixing of materials in the solum by the churning process caused by swell shrink clays as observed in deep Black Cotton Soils.

k. Braunification/ Rubification/ Ferruginisation:

• Release of iron from primary minerals and their dispersal as coatings on soil particales or as complexes with organic matter/ clay or as discreate aggregates to impart a brown to red colour to the soil.

l. Regur Formation:

• Formation of intensely dark colour complex of smectitic clay and humus. Dominant in black cotton soils.