Question

Which of followings are classified as nitrification inhibitor
(A). AM
(B). CDU
(C). IBDU
(D). N-serve
(E). Nitrapyrin
Choose the correct answer from the options given below:

• A. (A), (B) and (D) only.
• B. (A), (D) and (E) only.
• C. (A), (C) and (D) only.
• D. (B), (C) and (E) only.

Hint:

Be careful to distinguish between ______Nitrification Inhibitors______ (like Nitrapyrin/N-Serve, AM, DCD, and Neem cake) and ______Slow-Release Fertilizers______ (like IBDU, CDU, SCU).
Inhibitors alter soil microbial processes, while slow-release fertilizers release nutrients via slow physical or chemical breakdown.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Nitrification inhibitors are chemical compounds that temporarily delay the biological oxidation of ammonium (NH$_4^+$) to nitrite (NO$_2^-$) by depressing the activity of Nitrosomonas bacteria in the soil.
This helps reduce nitrogen losses through nitrate leaching and denitrification, thereby improving fertilizer-use efficiency.

Step 2: Detailed Explanation:
Let us analyze each of the given chemical compounds:
- (A) AM (2-amino-4-chloro-6-methylpyrimidine): This is a well-known synthetic ______nitrification inhibitor______ used to suppress Nitrosomonas activity.
- (B) CDU (Crotonylidene diurea): This is a ______slow-release nitrogen fertilizer______, not a nitrification inhibitor. It releases nitrogen slowly through chemical hydrolysis.
- (C) IBDU (Isobutylidene diurea): This is also a ______slow-release nitrogen fertilizer______ whose nitrogen release depends on its particle size and rate of dissolution in soil water.
- (D) N-serve:______ This is the commercial trade name for ______Nitrapyrin______. It is a highly effective, widely used ______nitrification inhibitor______.
- {(E) Nitrapyrin (2-chloro-6-(trichloromethyl)pyridine): This is the chemical name of the active ingredient in N-serve. It acts by inactivating the ammonia monooxygenase enzyme in Nitrosomonas bacteria.
Thus, (A), (D), and (E) are classified as nitrification inhibitors, while (B) and (C) are slow-release fertilizers.

Step 3: Final Answer:
The correct combination is (A), (D), and (E) only, which corresponds to option (B).