Question

The parameters of N use efficiency are
(A) Apparent N. recovery
(B) Agronomic efficiency
(C) Production efficiency
(D) Physiological N efficiency
Choose the correct answer from the options given below:

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

Hint:

Nitrogen use efficiency includes multiple measures like recovery, yield increase, and physiological response.

Answer 1

The Correct Option is C

All four parameters — Apparent N recovery, Agronomic efficiency, Production efficiency, and Physiological N efficiency — are recognized indicators to evaluate nitrogen use efficiency (NUE) in crop systems. Each reflects a different aspect of uptake, utilization, and yield benefit.

Answer 2

Defining each efficiency parameter: Apparent N recovery measures the fraction of applied nitrogen actually taken up by the crop; agronomic efficiency measures the yield increase per unit of nitrogen applied; physiological efficiency measures the yield increase per unit of nitrogen actually absorbed; and production efficiency relates total yield or biomass produced per unit of nitrogen present in the plant.
Each of these captures a distinct aspect of nitrogen use - uptake, yield response, internal utilisation, and overall productivity - none of them is redundant or invalid.
Since all four are legitimate, independently used indicators of nitrogen use efficiency, the option listing all four is correct.