Question

Match List-I with List-II. 

List-I (Soil Order)	List-II (Characteristics)
(A) Ultisols	(I) Deep soils with high organic matter content and more than 50% base saturation.
(B) Vertisols	(II) Clay-rich soils with swelling-shrinkage properties according to soil moisture content.
(C) Mollisols	(III) Base saturation \(< 35\%\) with argillic or kandic horizon.
(D) Alfisols	(IV) Soils that have argillic, kandic, or natric horizon and a base saturation of \(35\%\) or greater with ochric epipedon, but may have an umbric epipedon.

Choose the correct answer from the options given below.

• (A) - (I), (B) - (II), (C) - (III), (D) - (IV)
• (A) - (III), (B) - (II), (C) - (I), (D) - (IV)
• (A) - (I), (B) - (III), (C) - (IV), (D) - (III)
• (A) - (III), (B) - (IV), (C) - (I), (D) - (II)

Hint:

Remember: Ultisols and Alfisols are structurally similar, but Ultisols have low base saturation (\(\lt 35\%\)) due to more intense leaching, whereas Alfisols have high base saturation (\(\ge 35\%\)).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
USDA Soil Taxonomy classifies soils into 12 main soil orders based on diagnostic horizons, chemical properties, and moisture/temperature regimes.

Step 2: Detailed Explanation:
Let us match the characteristics of each soil order:
- (A) Ultisols are highly weathered, acidic forest soils with an argillic or kandic horizon and low base saturation (\(\lt 35\%\)), so (A) matches with (III).
- (B) Vertisols are dark, clay-rich soils dominated by swelling-shrinking clays (smectites) that form deep cracks when dry, so (B) matches with (II).
- (C) Mollisols are fertile grassland soils with a thick, dark surface layer (mollic epipedon) and high base saturation (\(\gt 50\%\)), so (C) matches with (I).
- (D) Alfisols are moderately weathered forest soils with an argillic/kandic/natric horizon and relatively high base saturation (\(\ge 35\%\)), so (D) matches with (IV).
The correct match combination is: (A)-(III), (B)-(II), (C)-(I), (D)-(IV).

Step 3: Final Answer:
Hence, the correct option is (B).