When adjusting soil pH with lime or sulfur, which guideline correctly guides product choice and timing?

• A. If pH is below target, lime to raise pH; if above target, sulfur to lower pH; consider buffering capacity, CEC, and re-testing after adjustment
• B. If pH is below target, sulfur; if above target, lime; apply lime and sulfur at once
• C. If pH is below target, apply lime gradually without re-testing
• D. Always apply both lime and sulfur regardless of pH

Answer: (A)

The main idea is to choose lime or sulfur based on where the soil pH currently sits relative to the target, and to verify the change with re-testing because soil pH changes are gradual and influenced by soil buffering and CEC. Lime is used to raise pH when the soil is too acidic (below target), while sulfur is used to lower pH when the soil is too alkaline (above target). Because soils have buffering capacity and different CEC, the amount needed can vary and the change can be slow, so re-testing after applying amendments is essential to avoid overshooting the target.

Applying sulfur when pH is already low would push pH further down, and applying lime when pH is already high would push it higher—both making the problem worse. Using both amendments at once ignores the actual need unless a specific, measured adjustment is required. Lime should not be added without re-testing, since you want to stop near the target pH rather than overshoot.