Read the following statements carefully regarding fertilizer amendments:
(A). 2-Chloro-6-trichloromethyl pyridine
(B). 2 Amino-4-chloro-6-methyl pyrimidine
(C). Phenyl phosphoro diamidate
(D). Dicyandiamide
Choose the correct answer from the options given below:
Show Hint
Nitrification inhibitors (Nitrapyrin, AM, DCD) keep nitrogen in the stable ammonium (\(\text{NH}_4^+\)) form, preventing leaching.
In contrast, Phenyl phosphoro diamidate (PPD) is a urease inhibitor designed to prevent gaseous ammonia volatilization from surface-applied urea.
Step 1: Understanding the Concept:
Nitrogen fertilizers applied to soils are subject to rapid leaching and volatilization losses.
To improve nitrogen-use efficiency, fertilizers are often mixed with inhibitors that slow down specific biochemical conversion steps in the soil.
Nitrification inhibitors selectively suppress the activity of Nitrosomonas bacteria, slowing the conversion of ammonium (\(\text{NH}_4^+\)) to nitrate (\(\text{NH}_3^-\)).
Urease inhibitors block the activity of the urease enzyme, slowing down the hydrolysis of urea to ammonia. Step 2: Detailed Explanation:
Let us analyze the chemical properties of each compound listed:
- (A) 2-Chloro-6-trichloromethyl pyridine (commonly known as Nitrapyrin or N-Serve): This is a highly effective, widely used commercial nitrification inhibitor.
- (B) 2-Amino-4-chloro-6-methyl pyrimidine (commonly known as AM): This is another established synthetic compound used specifically to inhibit the nitrification process in agricultural soils.
- (D) Dicyandiamide (commonly known as DCD): This is a water-soluble nitrification inhibitor that maintains nitrogen in the stable ammonium form for longer periods, reducing nitrate leaching.
- (C) Phenyl phosphoro diamidate (commonly known as PPD): This compound is a urease inhibitor, not a nitrification inhibitor. It blocks the active sites of the urease enzyme to slow down the hydrolysis of urea.
Since compounds (A), (B), and (D) belong to the class of nitrification inhibitors, they form a distinct grouping of nitrification-regulating amendments.
Therefore, Option (B) is the correct grouping of these agricultural amendments. Step 2: Final Answer:
The correct grouping of these amendments corresponds to (A), (B) and (D) only.
