Consider the following statements regarding soils :

1. Soils having a very high content of sodium and calcium and pH of more than 7.0 are alkaline soils.

2. Black cotton soil had developed on the Deccan basaltic lava under hot and humid conditions.

3. Laterite soils are characterised by a deep weathered layer from which silica has been leached.

Which of the statements given above is/are correct?

The correct answer is 2 and 3 only.

Key PointsSoils Characteristics

• Alkaline Soils:
  • Alkaline soils are typically characterized by a high pH level, usually above 7.0.
  • They often contain a high concentration of salts, particularly sodium and sometimes calcium.
  • However, the presence of both sodium and calcium in very high concentrations is uncommon together in alkaline soils.
  • Generally, soils with high sodium content are referred to as sodic soils.
  Hence, statement 1 is incorrect.
• Black Cotton Soil:
  • Black cotton soil, also known as Regur soil, is predominantly found in the Deccan Plateau region of India.
  • It is formed from the weathering of basaltic lava under specific climatic conditions that include hot and humid weather.
  • This soil is rich in clay minerals and has high moisture retention properties, making it suitable for cotton cultivation.
  Hence, statement 2 is correct.
• Laterite Soils:
  • Laterite soils are heavily leached soils found in tropical and subtropical regions with high rainfall.
  • They are characterized by a deep weathered layer from which silica and other soluble minerals have been leached out.
  • These soils are rich in iron and aluminum oxides, which give them a distinctive red or yellow color.
  Hence, statement 3 is correct.

Additional Information

• Soil pH:
  • The pH of soil is a measure of its acidity or alkalinity.
  • A pH below 7 indicates acidic soil, while a pH above 7 indicates alkaline soil.
  • Soil pH affects nutrient availability and microbial activity, which are crucial for plant growth.
• Deccan Basaltic Lava:
  • The Deccan Plateau in India is known for its extensive basaltic lava flows that date back to the Cretaceous period.
  • These lava flows have weathered over time to form fertile soils like black cotton soil.
• Laterite Soil Uses:
  • Laterite soils are used for building materials and road construction due to their hardness and ability to withstand weathering.
  • In agriculture, they are less fertile but can be improved with proper management and fertilization.
• Soil Management:
  • Understanding the characteristics of different soils is crucial for effective soil management and sustainable agriculture.
  • Soil amendments, crop rotation, and proper irrigation are some techniques used to manage soil health.