In the standard representation of fertilizer composition (N-P-K), what does the second number indicate?

• A. The percentage of phosphorus (as P2O5)
• B. The percentage of potassium (as K2O)
• C. The percentage of nitrogen (as N)
• D. The percentage of calcium (as CaO)

Answer: (A)

Verified step by step guidance

1. Understand that the standard fertilizer composition is represented by three numbers in the format N-P-K.
2. Recognize that each number corresponds to the percentage by weight of a specific nutrient in the fertilizer.
3. Know that the first number (N) represents the percentage of nitrogen (N) in the fertilizer.
4. Know that the second number (P) represents the percentage of phosphorus, but specifically expressed as phosphorus pentoxide (P\_2O\_5).
5. Know that the third number (K) represents the percentage of potassium, expressed as potassium oxide (K\_2O).