How is lime requirement determined in turf management, and what is the primary effect of liming on soil chemistry?

• A. Lime requirement is determined by soil pH and buffering capacity from a soil test; liming raises pH and increases calcium and magnesium availability, reducing aluminum toxicity in acidic soils.
• B. Lime requirement is determined by turf species alone; liming lowers pH.
• C. Lime requirement determined by rainfall; liming increases sodium.
• D. Lime requirement determined by soil texture; liming reduces calcium.

Answer: (B)

The important idea is that lime requirement is determined from a soil test that examines soil pH and buffering capacity. A lime recommendation is based on how strongly the soil resists pH change and what pH is needed to reach a level where nutrients are available and toxicity is controlled. The primary effect of liming is to raise soil pH and supply calcium and magnesium. As pH increases, aluminum becomes less soluble and less toxic to plant roots, and the added Ca and Mg help replace acidic cations on soil exchange sites, improving nutrient availability and root health. Choices that tie lime need to turf species, rainfall, or soil texture, or that claim liming lowers pH or raises sodium, don’t reflect how lime interacts with soil chemistry.