RAS question
Bhangar (old alluvium) differs from Khadar (new alluvium) in that Bhangar:
Correct answer: (D) Is higher in elevation, contains kankar (calcareous nodules), and is less fertile.
Bhangar is old alluvium that lies above the flood plain, has a higher concentration of kankar or calcareous nodules, and is less fertile than Khadar.
Explanation
Bhangar and Khadar are the age-based divisions of alluvial soil in the northern plains. NCERT identifies Bangar as old alluvium and Khadar as new alluvium, and notes that Bangar has a higher concentration of kankar nodules while Khadar has finer particles and is more fertile. The standard geomorphic distinction is clear: Bhangar forms the older, relatively elevated alluvial terraces above the active flood plain, so it is not renewed every year by floods. Khadar, by contrast, is the newer low-lying alluvium deposited in flood plains and refreshed by annual flooding, which makes it especially suitable for intensive agriculture. The Ganga-Yamuna doab shows both forms clearly.
Why the other options are wrong
- (A) Bhangar is not a coastal soil; it is an inland form of old alluvium associated with riverine alluvial plains such as the Ganga-Yamuna doab.
- (B) Annual flood deposition and higher fertility describe Khadar, the newer alluvium, not Bhangar.
- (C) Volcanic soil is not part of the Bhangar-Khadar distinction in the Indo-Gangetic alluvial plain; the distinction is based on age, position and kankar content.
Concept
Indian soils in RAS physical geography often require the age-based classification of alluvial soils. Bhangar-Khadar differences connect geomorphology, river plains and agricultural fertility in a single core concept.