Discussing briefly the factors affecting the soil formation, describe the characteristics of any one type of soil.| UP PCS Optional Geography Mains Paper 1 2019

Discussing briefly the factors affecting soil formation, describe the characteristics of any one type of soil.
( UPPSC / UPPCS, 2019, 15 Marks)
मिट्टी के निर्माण को प्रभावित करने वाले कारकों पर संक्षेप में व्याख्या करते हुए, किसी एक प्रकार की मिट्टी की विशेषताओं का वर्णन कीजिये।

  • Weathering,
  • Erosion,
  • Transportation,
  • Parent materials
  • Topography
  • Climate
  • Biological activities
  • Time


Soil is the result of interaction among the lithosphere, atmosphere, hydrosphere, and biosphere. The soil is a dynamic medium in which many chemicals, physical, and biological activities continuously make changes.

Process of soil formation:
Two processes of soil formation:
  • Weathering of parent rock
  • Weathered or transported mater are colonized by bacteria, mosses, and lichen leading to soil formation.
Factors affecting soil formation:

The following five basic factors control soil formation:

  • Parent materials
  • Topography
  • Climate
  • Biological activities
  • Time
The combination of the above five factors determines the types of soils in a particular area.
Parent materials:

  • Parent rock determines the characteristics of the soil such as chemical composition like pH value and physical properties like soil texture, soil structure, soil porosity, permeability, and soil color. For example, red soil is formed by the parent material of iron.


  • The soil will be thin on the steeper slope and thick over flat surfaces or on gentle slopes; this is because of favorable soil formation due to slow erosion and percolation of water into depth.

  • Climatic elements are involved in soil formation.
  • Moisture: in terms of intensity, frequency, duration of precipitation, evaporation, humidity.
  • Temperature: in terms of seasonal and diurnal variation. A larger variation of temperature leads to expansion and contraction of soil; as the result, rocks break.
  • Precipitation enhances chemical, biological activities, and erosion activities.
  • Excess waters help downward transportation of soil components and removal of silt from the soil. Laterite soil formed.
  • Dry region due to capillary action, groundwater brought up to surfaces. Soils become salty.

Biological activities:

  • Vegetation release acids that enhance chemical weathering. Flora and fauna, both are favorable for soil formation.


  • The length of time determines the maturity of soil profile( thickness) development.

Laterite Soil:

Laterite soil formed through the process of lateralization. The suitable climatic condition for the lateralization process is high temperature and heavy precipitation.
Distribution of laterite soil
Distribution of laterite soil

The following are the characteristics of laterite soil:

  • Fertility is nearly absent in the upper layer of soil profile as water-soluble minerals from the upper layer of soil get leached to the lower layer of soil due to heavy precipitation.
  • The Humus content of the soil is low due to high temperature and the precipitation decomposition rate is faster.
  • It has high fertility in the Lower profile of the soil.
  • Because of the above two features, the soil is not suitable for small plants and agriculture but highly suitable for larger plants.
  • Laterite soil is found in the equatorial region of the earth. The distribution of laterite soil is shown in the above figure.
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