Different type of Soils

Type of soils :-

1. Aeolian soils :-

- The soils transported by wind from one place to another is called as Aeolian soils.

2. Alluvial soils :-

- The soils transported by water from one place to another is called as Alluvial soils.

- Found in river valleys, floodplains etc.

- It is more fertile because it is uniformly graded soil which contain sand, silt and clay (loam) moreover alluvial soil contains potash, phosphoric acid and lime which is ideal for the paddy, wheat and maize.

- Its PH value is nearly between 6.6 to 8.

3. Bentonite :-

- Very high percentage of clay mineral Montmorillonite.

- It usually forms from weathering of volcanic ash in seawater.

- Highly water absorbent.

- Highly plastic clay.

- High shrinkage and swelling characteristics.

4. Black cotton soils :-

- Black in Colour.

- Suitable for growing cottons.

- Formed from Basalt or Trap rocks. [ Residual deposits ]

- soil contain essential Clay minerals as Montmorillonite.

- Engineering properties :-

a) High plasticity

b) High Compressibility

c) Low bearing capacity

d) Low shearing strength

e) High shrinkage and swelling characteristics.

- very difficult to work with this soil.

5. Boulders :-

- Rock Fragments more than 300mm in size.

6. Calcareous soils :-

- Contain large quantity of calcium carbonate (CaCO₃).

- Such soils effervesce when tested with HCL (Hydrochloric acid).

7. Caliche :-

- Contain gravel, sand and silt.

- The particles are cemented by calcium carbonate.

8. Clay :-

- Fine-grained soil

- Particle size less than 0.002mm (2µ). [1µ = 1micron = 10⁻³mm = 10⁻⁶mm = 10⁻⁴mm].

9. Cobbles :-

- Size range between 80mm to 300mm.

10. Cohesive soils :-

- Soils in which the adsorbed water and particle attraction act such that it deforms plastically at varying water content are known as cohesive soils. Examples :- silt, clay, loam, etc.

- Fine-grained soils.

- Easily deformable soils.

- Sticky soil.

11. Cohesionless soils (Non-Cohesive soils) :-

- Any free running type soil, such as sand, gravel, etc.

- Coarse-grained soils.

- Cohesionless soil is soil that contains elements that do not stick together.

12. Collapsible soils :-

- The soils which cannot be converted into any shape and the deposit has less stability.

- Examples :- Loess and Sand Dunes

13. Colluvial soils :-

- Soils which are transported under the action of gravity.

14. Cummulose Soils :-

- mixture of peat and much soil is termed as cummulose Soil.

15. Desert Soils [ arid soil ] :-

- This soil is formed from arid condition with practically negligible rainfall.

- Highly previous and have a low density.

- Requires densification to increase its bearing capacity and shearing strength.

- plants that grow in these soils are Cacti.

16. Expansive clays :-

- These are prone to large volume changes as the water content is changed.

- Contain → Mineral Montmorillonite.

17. Forest soils :-

- Regions of high rainfall.

- Humus content is less and thus the soil is acidic.

18. Gravel :-

- Coarse-grained soils

- Size between 4.75mm to 80mm.

19. Gumbo soils :-

- Black Colour

- Sticky

- Highly plastic soils

20. Humus :-

- Humus is a dark, organic material that forms in soil when plant and animal matter decays. ( organic amorphous earth of the topsoil )

- Consists of partly decomposed vegetal matter

- Not suitable for Engineering works.

21. Kankar :-

- Impure form of lime stone

- Contain calcium carbonate mixed with some siliceous material.

22. Lateritic soils :-

- Residual soils formed in tropical regions.

- Very soft when freshly cut but become hard after long exposure.

23. Loam :-

- Mixture of Sand, Silt and Clay.

- the term loam is generally used in Agronomy

→ Agronomy :- Agronomy is the science and technology of producing and using plants in agriculture for food, fuel, fiber, and land restoration.

- Loam soils is well suited to tilling operation.

→ Tillage :- Tillage is the agricultural preparation of soil by mechanical agitation of various types, such as digging, stirring, and overturning.

24. Loess :-

- Wind blow deposit of silt.

25. Marl :-

- It is stiff, marine calcareous clay of greenish colour.

26. Moorum :-

- The word moorum is derived from a Tamil word, meaning powdered rock.

- Consists of small pieces of disintegrated rock or shale, with or without boulders.

27. Muck :-

- Mixture of fine soil particles and highly decomposed organic matter.

- Black in colour and extremely soft consistency.

- Not used for Engineering work.

- Organic matter is in an advanced stage of decomposition.

28. Peat :-

- Formed from vegetal matter under condition of excess moisture, such as in swamps.

- Highly compressible and not suitable for foundation.

29. Red soils :-

- seen mainly in low rainfall area.

- Red colour due to ferric oxide. The lower layer is reddish yellow or yellow.

- Red soils are generally derived from crystalline rock.

- They are usually poor growing soils, low in nutrients and humus and difficult to cultivate because of its low water holding capacity.

30. Sand :-

- Coarse-grained soil

- size between 0.075mm to 4.75mm.

31. Silt :-