Environment & Ecology : Terrestrial Ecosystems

Q 1 / 5

UPSC CSE Prelims 2023

Consider the following statements :
  1. Statement-I : The soil in tropical rain forests is rich in nutrients.
  2. Statement-II : The high temperature and moisture of tropical rain forests cause dead organic matter in the soil to decompose quickly.
Which one of the following is correct in respect of the above statements?

EXPLANATION

Correct Option (d)

Statement-I is incorrect, while Statement-II is correct.

Explanation

Explanation for Statement-I:

  • Tropical rainforest soils are generally poor in nutrients. Despite the lush vegetation, most nutrients are held within the living biomass (plants and decomposing organic matter) rather than accumulating in the soil itself.
  • Heavy rainfall leads to rapid leaching of soluble nutrients from the soil profile, further depleting its nutrient content.
  • The quick uptake of released nutrients by the dense vegetation also prevents nutrient accumulation in the soil.

Explanation for Statement-II:

  • The consistently high temperatures and abundant moisture characteristic of tropical rainforests create optimal conditions for decomposer organisms (bacteria, fungi).
  • This environment results in a very rapid decomposition of dead organic matter on the forest floor.
  • While decomposition is fast, the released nutrients are immediately absorbed by the dense vegetation or leached away by rainfall, preventing their long-term retention in the soil.

Incorrect Options

  • Options (a), (b), and (c) are incorrect because Statement-I, which asserts that the soil in tropical rainforests is rich in nutrients, is factually inaccurate. Tropical rainforest soils are characterized by low nutrient content.
SOURCENCERT Class 11 Geography Chapter 15: Life on the Earth, Environment by Shankar IAS, Chapter 3: Terrestrial Ecosystems