Macronutrients are required by the plant in large quantities for basic plant growth and development. The macronutrients include: nitrogen, phosphorus and potassium. Secondary nutrients are required in moderate amounts and are less likely to limit crop growth. These nutrients include: calcium, magnesium and sulphur. 1  Nitrogen. 2  Phosphorus. 3  Potassium. 4  Calcium. 5  Magnesium. 6  Sulfur.