What does SMP buffer pH method estimate?

• A. Measures soil salinity levels
• B. Estimates the lime requirement to raise soil pH to a target
• C. Predicts future rainfall
• D. Indicates organic matter content

Answer: (B)

SMP buffer pH is used to estimate how much lime a soil needs to raise its pH to a target level. The test uses a standardized buffer solution and soil sample to generate a buffer pH value that is then interpreted against a calibration relationship to determine the lime requirement. In practice, this helps determine the amount of lime—usually expressed as tons per acre or tons per hectare—that should be applied to reach the desired pH, improving nutrient availability and soil biology for rangeland plants. This method is specifically about correcting soil acidity, not about measuring salinity, predicting rainfall, or judging organic matter content, which require different tests.