What is buffer pH used for in soil testing?

• A. It measures soil moisture.
• B. It helps determine the amount of lime needed to neutralize hydrogen ions and adjust soil pH.
• C. It estimates nitrogen availability.
• D. It determines moisture holding capacity.

Answer: (B)

Buffer pH in soil testing is a measure used to estimate how much lime is needed to raise soil pH to a desired target. It works by using a standardized buffer solution that interacts with the soil’s acidity, reflecting the soil’s buffering capacity and the amount of hydrogen (and aluminum) that must be neutralized on the soil’s exchange sites. The result isn’t the exact current pH, but the amount of lime required to reach the target pH, guiding lime application decisions. This is different from measures of soil moisture, nitrogen availability, or moisture-holding capacity, which are not about counteracting soil acidity with lime.