How does soil pH influence the availability of major nutrients to turfgrasses, and what pH range optimizes most turf species?

• A. pH affects only micronutrients, not major nutrients.
• B. Most turf nutrients are most available around pH 6.0–7.0; P becomes less available below 6.0; iron and manganese availability increase in more acidic soils, while calcium and magnesium availability improves near neutral pH.
• C. pH has no effect on nutrient availability.
• D. When pH is high, all nutrients become more available.

Answer: (B)

Soil pH controls how nutrients exist and move in the soil solution. Nutrients aren’t just present or absent; their chemical forms change with pH, which affects how easily roots can take them up. For most turfgrasses, a pH around 6.0 to 7.0 provides the best balance where major nutrients are reasonably soluble and accessible.

Phosphorus, crucial for root development and energy transfer, is most available near this range and becomes less available when the soil is more acidic (below about 6.0) because it tends to fix with iron and aluminum. In more acidic soils, iron and manganese become more soluble, so they are more readily taken up. Calcium and magnesium, important for structure and metabolism, are more readily available near neutral pH, where their minerals stay soluble enough for roots to absorb.

That’s why aiming for a pH in roughly 6.0–7.0 helps most turf species access the major nutrients they need. If tests show the soil is too acidic or too alkaline, adjusting with lime or sulfur moves the pH toward that range, improving nutrient availability and turf health.