Question

Given below are two statements
Statement I: Tectona grandis is a good example of nitrogen‐fixing tree
Statement II: Transfer of nutrients from trees to crops in the agroforestry system is through pruning, leaf drops or root decomposition
In light of the above statements, choose the correct answer from the options given below

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Hint:

Teak is a "Greedy" tree—it needs lot of nutrients (especially Calcium) to grow good wood. It never fixes nitrogen. Don't confuse it with Leucaena or Casuarina!

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks to validate statements about tree physiology (nitrogen fixation) and nutrient cycling mechanisms in agroforestry.

Step 2: Detailed Explanation:

• Nitrogen Fixation (Statement I): Tectona grandis (Teak) belongs to the Lamiaceae family. It is not a nitrogen-fixing species. Nitrogen-fixing trees are primarily legumes (Family Fabaceae, like Acacia or Leucaena) or actinorhizal trees (like Casuarina). Teak is a heavy nutrient demander, not a fixer. Thus, Statement I is false.

• Nutrient Transfer (Statement II): In agroforestry, trees act as biological fertilizer factories. When leaves fall (leaf drop) or are pruned and added to the soil as mulch, they decompose. Similarly, fine roots that die and decompose under the soil surface release nutrients directly into the crop root zone. This is the primary pathway for nutrient recycling. Thus, Statement II is true.

Step 3: Final Answer:
Statement I is incorrect, while Statement II correctly identifies nutrient cycling pathways.