In the context of soil fertility, what is meant by a limiting nutrient for plant growth?

• A. A nutrient in shortest supply relative to plant demand that restricts growth even if other nutrients are abundant
• B. A nutrient that increases plant growth regardless of its concentration in the soil
• C. Any nutrient that is toxic to plants at low concentrations and therefore prevents growth
• D. A nutrient that plants never need because it is always supplied by the atmosphere

Answer: (A)