Which one of the following is the soil order of old alluvial soils?

Correct option is A

The correct answer is (A) Inceptisols

Explanation:
• Alluvial soils in India are broadly divided into Khadar (new alluvium) and Bhangar (old alluvium).
• Entisols (B) are very young soils with no profile development, representing new alluvial soils (Khadar) that receive fresh deposits during floods.
• Inceptisols (A) are slightly more developed soils that show the beginning of horizonation (like a B horizon). These represent old alluvial soils (Bhangar) which have been in place long enough for some soil-forming processes to act on them.
• Inceptisols are the most widely distributed soil order in India, covering a large portion of the Indo-Gangetic plains.

Information Booster:
• There are 12 soil orders in the USDA Soil Taxonomy.
• Bhangar soils often contain 'Kankar' (calcareous nodules).
• The sequence of soil development is typically: Entisol $\rightarrow$ Inceptisol $\rightarrow$ Alfisol/Mollisol $\rightarrow$ Ultisol $\rightarrow$ Oxisol.

Additional Knowledge:
• Histosols (Option C): Organic soils (peat/muck soils) found in marshes and bogs.
• Mollisols (Option D): Highly fertile grassland soils with a thick, dark A-horizon; rare in India but common in the American Prairies or Russian Steppes.