Question

Method suitable for managing rainwater in black soil is

• A. Bunding
• B. Broad bed and furrow
• C. Terracing
• D. Trenching

Hint:

Black soils (Vertisols) $\rightarrow$ Broad Bed and Furrow (BBF) system.
Light sandy/red soils $\rightarrow$ Contour bunding.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Deep black soils (Vertisols) have high swelling and shrinking montmorillonite clay content, resulting in very low saturated hydraulic conductivity, waterlogging during monsoons, and deep cracking in dry spells.

Step 2: Detailed Explanation:
In deep black soils (Vertisols):
- Traditional contour bunding fails because water stagnates behind bunds, leading to waterlogging and bund breaches due to soil swelling/slumping.
- The Broad Bed and Furrow (BBF) system (developed by ICRISAT) consists of broad raised beds (\(100\text{--}150\text{ cm}\) wide) separated by shallow graded furrows (\(30\text{--}50\text{ cm}\) wide on a \(0.4\text{ to } 0.8\%\) grade).
- BBF provides safe disposal of excess storm runoff without erosion, prevents waterlogging on the beds, and enhances in-situ moisture conservation.

Step 3: Final Answer:
Therefore, the method suitable for managing rainwater in black soil is Broad bed and furrow, matching option (B).