Which option is NOT a primary plant nutrient (NPK) essential for growth?

Which option is NOT a primary plant nutrient (NPK) essential for growth?

• A. Nitrogen
• B. Phosphorus
• C. Potassium
• D. Calcium

Answer: (D)

Primary nutrients are the elements plants need in the largest amounts to grow and develop, typically supplied as N, P, and K in fertilizers. Nitrogen supports leafy growth and proteins, phosphorus fuels energy transfer and root development, and potassium helps regulate water movement and enzyme activity. Calcium, while essential for sturdy cell walls and proper signaling, is categorized as a secondary nutrient because it is required in smaller amounts compared with the primary trio. So the nutrient shown that is not one of the primary plant nutrients is calcium.

Primary nutrients are the elements plants need in the largest amounts to grow and develop, typically supplied as N, P, and K in fertilizers. Nitrogen supports leafy growth and proteins, phosphorus fuels energy transfer and root development, and potassium helps regulate water movement and enzyme activity. Calcium, while essential for sturdy cell walls and proper signaling, is categorized as a secondary nutrient because it is required in smaller amounts compared with the primary trio. So the nutrient shown that is not one of the primary plant nutrients is calcium.