Question

Which one of the following soil types shows self-ploughing characteristics due to its expansion and contraction?

• A. Red Soil
• B. Black Soil
• C. Laterite Soil
• D. Arid Soil

Answer 1

Answer:

B. Black Soil

• Correct Answer: Option B - Black Soil

• Black soil, also known as regur soil or black cotton soil, is famous for its self-ploughing characteristics due to its significant expansion and contraction properties. These soils have a high content of expandable clay minerals, particularly montmorillonite, which gives them their distinctive behavior:

• During the dry season, black soils shrink and develop deep, wide cracks (sometimes up to 10-15 cm wide and 1 meter deep).

• During the rainy season, these soils absorb water, swell considerably, and the cracks close up.

• This continuous process of expansion when wet and contraction when dry creates an internal movement in the soil that turns it over naturally - hence the term "self-ploughing."

• This characteristic makes black soils fertile without requiring much external plowing, though it also causes engineering challenges for construction.

• Black soils are predominantly found in the Deccan Plateau region of India covering parts of Maharashtra, Gujarat, Madhya Pradesh, and parts of Tamil Nadu. They are highly suited for growing cotton, hence also called "black cotton soils."

• The other soil types listed (Red Soil, Laterite Soil, and Arid Soil) do not exhibit this distinctive expansion-contraction property to the same significant degree.