In terms of fertilization, what does the number "10-10-10" represent?

The number "10-10-10" on a fertilizer bag indicates the percentages of three essential nutrients: nitrogen, phosphorus, and potassium. Each number corresponds to the percentage by weight of these macronutrients contained in the fertilizer. In this case, 10-10-10 means that the fertilizer has 10% nitrogen, 10% phosphorus, and 10% potassium. This balanced formulation is often referred to as a "complete fertilizer," as it provides equal amounts of these key nutrients, which are critical for plant growth and health.

Understanding this notation is crucial for selecting the right fertilizer for specific plant needs, as different plants may require different ratios of these nutrients. The other options do not accurately describe what "10-10-10" represents; for example, herbicide content, pH balance, and volume requirements are separate considerations unrelated to the specified nutrient percentages.