What is the Mehlich 3 solution used for?

• A. To measure soil moisture.
• B. To extract phosphorus and potassium values from soil for testing.
• C. To adjust pH.
• D. To extract nitrogen.

Answer: (B)

Mehlich 3 is a soil testing extractant used to pull plant-available nutrients from the soil so labs can measure them. Its mild acidic solution dissolves phosphorus and potassium that are accessible to plants, giving a value that helps determine fertilizer needs. While it can release other nutrients as well, the main purpose in routine testing is to estimate the available phosphorus and potassium in the soil. It isn’t used to measure soil moisture or to adjust soil pH, and nitrogen is typically assessed by other methods.