Which element is listed as the one needed in the greatest amount for turfgrass growth and metabolism?

• A. None of these elements
• B. Phosphorus
• C. Iron
• D. Calcium

Answer: (A)

The main idea here is understanding which nutrient turfgrass needs in the largest amount. In most plants, and especially in turfgrass, nitrogen is the element required in the greatest quantity because it fuels leaf growth, proteins, and chlorophyll, all of which drive metabolism and overall vigor. Phosphorus, iron, and calcium are essential too, but they are needed in smaller amounts relative to nitrogen (iron is a micronutrient, calcium supports cell walls and signaling, and phosphorus is crucial for energy transfer and root development). Since nitrogen isn’t listed among the options, the best pick is the one that says none of these elements—the true driver (nitrogen) isn’t provided.