Question

An increase in growth takes place in a grassy field where phosphorus has been added as compared to no growth in the second area where nitrogen has been added. The limiting nutrient for this ecosystem is

• A. Nitrogen, because addition of this nutrient did not affect plant growth.
• B. Phosphorus, because addition of this nutrient did not affect plant growth.
• C. Nitrogen, because addition of this nutrient resulted in increased plant growth.
• D. Phosphorus, because addition of this nutrient resulted in increased plant growth.
• E. Both nitrogen and phosphorus, because addition of one nutrient increased plant growth.

Answer 1

Answer: (D)

Phosphorus, because addition of this nutrient resulted in increased plant growth.

The limiting nutrient is the one which is present in the limited quantity at the time and thus determines the growth and development of the vegetation. In the given example, an addition of nitrogen does not increase the growth of grassy field while the addition of phosphorus does. This means nitrogen is already present in ample quantities in the field but phosphorus availability is limited i.e., phosphorus is limiting nutrient of the field.

Therefore, the correct answer is option D.