The black cotton soil of India has been formed due to the weathering of
[UPSC Civil Services Exam – 2021 Prelims]
(a) brown forest soil
(b) fissure volcanic rock
(c) granite and schist
(d) shale and limestone
Answer: (b)
Explanation:
- Black soil, also known as regur soil, is predominantly composed of volcanic rocks that formed in the Deccan Plateau, particularly the Deccan and Rajmahal traps.
- It has a high clay content, with at least 62% clay, giving it a highly argillaceous nature.
- Black soils located in valleys are more fertile than those found in uplands.
- The black color of the soil is attributed to the presence of titaniferous magnetite or iron and black constituents from the parent rock.
- Due to its high moisture retention capacity, black soil swells significantly when moist. It is particularly challenging to work with during the rainy season as it becomes very sticky.
Therefore, option (b) is the correct answer.
