Question

Arrange the following consequences of submergence in the soil in the correct sequence:
(A). Depletion of soil oxygen,
(B). Accumulation of toxic substances like hydrogen sulfide,
(C). Loss of beneficial soil organisms,
(D). Increased soil pH in acidic soil.

• A. (A), (C), (B), (D)
• B. (A), (B), (C), (D)
• C. (B), (A), (D), (C)
• D. (C), (B), (D), (A)

Hint:

Understand the biological and chemical changes occurring during waterlogging to answer sequence-based soil science questions.

Answer 1

The Correct Option is B

Step 1: Flooding first depletes free oxygen (A) via aerobic respiration.
Step 2: Anaerobic conditions then let sulfate-reducers build up toxic H2S and similar compounds (B).
Step 3: Toxicity and low oxygen next kill off beneficial aerobic soil organisms (C).
Step 4: Long-term reduction reactions finally raise pH in acidic soils (D).
Correct option: (A), (B), (C), (D).