Question

Removal of lime in solution from upper to the lower part of the soil profile leads to the formation of -----

• A. Saline soils
• B. Regur
• C. Kari soils
• D. Kankar

Hint:

The formation of Kankar nodules is a diagnostic feature of soils in semi-arid climates, indicating incomplete leaching of calcium carbonate from the profile.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The translocation of calcium carbonate ($\text{CaCO}_3$, lime) within a soil profile is a major soil-forming process (calcification) in semi-arid and arid regions.

Step 2: Detailed Explanation:
- In semi-arid regions, limited rainfall dissolves calcium carbonate in the upper soil horizons and carries it downward in solution.
- As the water moves downward and evaporates, or as the $\text{CO}_2$ concentration changes, the calcium carbonate precipitates in the lower part of the profile.
- Over time, this accumulated lime aggregates into hard nodules or concretions known locally as "Kankar" (calcic horizon).
- Regur refers to black cotton soils (Vertisols).
- Kari soils are acid sulfate soils found in Kerala.

Step 3: Final Answer:
The translocation and accumulation of lime leads to the formation of Kankar.