Which amendment is commonly used to lower soil pH?

Which amendment is commonly used to lower soil pH?

• A. Limestone
• B. Elemental sulfur
• C. Lime
• D. Potassium chloride

Answer: (B)

Lowering soil pH is achieved by adding an amendment that becomes acidic in the soil. Elemental sulfur is the standard choice because soil microbes oxidize it to sulfuric acid, which gradually increases hydrogen ion concentration and lowers pH. The rate of acidification depends on temperature, moisture, and soil biology, so it often takes months to years to reach the target pH. Limestone or lime are alkaline amendments that raise pH, not lower it, so they’re used when soil is too acidic, not when you want to make it more acidic. Potassium chloride is a fertilizer and does not meaningfully change soil pH; it’s used for potassium nutrition rather than pH adjustment.

Lowering soil pH is achieved by adding an amendment that becomes acidic in the soil. Elemental sulfur is the standard choice because soil microbes oxidize it to sulfuric acid, which gradually increases hydrogen ion concentration and lowers pH. The rate of acidification depends on temperature, moisture, and soil biology, so it often takes months to years to reach the target pH. Limestone or lime are alkaline amendments that raise pH, not lower it, so they’re used when soil is too acidic, not when you want to make it more acidic. Potassium chloride is a fertilizer and does not meaningfully change soil pH; it’s used for potassium nutrition rather than pH adjustment.