Explanation: In the Upper and Middle Ganga plain, two different types of alluvial soils have developed, viz. Khadar and Bhangar.

• Khadar is the new alluvium and is deposited by floods annually, which enriches the soil by depositing fine silts.
• Bhangar represents a system of older alluvium, deposited away from the flood plains.
• Both the Khadar and Bhangar soils contain calcareous concretions (Kankars).

Source: NCERT – Fundamental of Physical Geography