Agronomy Degree Practice Exam

What type of plant nutrients are calcium, magnesium, and sulfur classified as?

1. Essential

2. Micro

3. Primary

4. Secondary

The correct answer is: Secondary

Calcium, magnesium, and sulfur are classified as secondary nutrients in plant nutrition. These nutrients, while essential for plant growth, are required in smaller quantities compared to primary nutrients, which are nitrogen, phosphorus, and potassium. Secondary nutrients play vital roles in various physiological processes. For instance, calcium is crucial for cell wall structure and stability, and it also helps in membrane function and enzyme activity. Magnesium is a central component of chlorophyll, which is essential for photosynthesis, and it also plays a role in enzyme activation. Sulfur is important for the synthesis of amino acids, vitamins, and other biomolecules. While all these nutrients are essential for healthy plant development, the classification into primary and secondary helps to prioritize nutrient management practices based on the amounts needed by plants. Micro nutrients, on the other hand, typically include elements like iron, manganese, and zinc, which plants require in even smaller amounts compared to secondary and primary nutrients.