Texas FFA Nursery Landscape Practice Exam

A 50-pound bag of 5-10-15 fertilizer contains how many pounds of nitrogen?

1. A. 5

2. B. 10

3. C. 15

4. D. 2.5

The correct answer is: D. 2.5

To determine how many pounds of nitrogen are in a 50-pound bag of fertilizer labeled 5-10-15, it is essential to understand the meaning of the numbers in the fertilizer grade. The numbers represent the percentage by weight of nitrogen, phosphorus, and potassium, respectively; in this case, 5% nitrogen, 10% phosphorus (P2O5), and 15% potassium (K2O). To find the amount of nitrogen in the bag, you would calculate 5% of the total weight of the fertilizer. This can be done by multiplying the total weight of the bag (50 pounds) by the percentage of nitrogen (5% or 0.05): 50 pounds × 0.05 = 2.5 pounds. Thus, the bag contains 2.5 pounds of nitrogen. This demonstrates the significance of knowing how to interpret fertilizer grades and perform basic percentage calculations to determine the composition of the fertilizer.