The fertilizer element most related to root growth in plants is

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

Answer: (D)

The nutrient that most directly supports root growth is potassium. It helps regulate water balance and turgor in root cells, enabling easier cell expansion and root elongation. It also activates enzymes involved in energy use and sugar transport, so energy produced in the leaves can be efficiently delivered to and used by roots to grow and develop a strong root system. While nitrogen mainly drives leafy, upright growth and phosphorus supports early root establishment and energy transfer, potassium has the strongest influence on ongoing root development and root health. Calcium strengthens cell walls but is less about promoting root elongation, so potassium remains the most closely linked to root growth.