If Bray P1 value is 20, what is the Mehlich 3 value approximately?

• A. 27
• B. 14
• C. 20
• D. 40

Answer: (A)

Mehlich-3 values tend to be higher than Bray P1 values for the same soil because Mehlich-3 is a stronger, more universal extractant that pulls P from a wider range of soil fractions. In many Ohio soil-test guidelines, a rough conversion is that Mehlich-3 P is about 1.3 times the Bray P1 P value. So with a Bray P1 value of 20, the Mehlich-3 value would be around 26–27. Among the options, 27 is the closest estimate. The other numbers are either notably lower (14), the same (20), or much higher (40) than what the typical conversion would give.