Question

The pH of optimum availability of Nitrogen is

• A. 6.5 - 7.5
• B. 5.5 - 6.5
• C. 7.5 - 8.5
• D. 8.5 - 9.5

Hint:

Nutrient availability and pH:
- Nitrogen: 6.5-7.5 (optimum).
- Phosphorus: 6.0-6.5.
- Micronutrients: More available at acidic pH.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
This question tests knowledge of nutrient availability in relation to soil pH.

Step 2: Detailed Explanation:
The pH of optimum availability of nitrogen is 6.5 - 7.5 (A).
Nitrogen availability is highest in this pH range because:
- Nitrification is optimal at pH 6.5-7.5.
- Nitrogen fixation is optimal at near-neutral pH.
Other ranges:
- 5.5 - 6.5 (B): Available, but not optimal.
- 7.5 - 8.5 (C): May cause loss of nitrogen as ammonia.
- 8.5 - 9.5 (D): Nitrogen availability is reduced.
Thus, nitrogen is most available at pH 6.5-7.5.

Step 3: Final Answer:
Thus, the pH of optimum availability of nitrogen is 6.5 - 7.5, which corresponds to option (A).
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