− | In humid temperate regions, the optimum soil pH range for most plants is between 6.0 and 7.5 (Craul, 1999). More acidic soils inhibit the solubility of potassium, sulfur, calcium, magnesium and molybdenum, while increasing the solubility of iron, manganese, boron, copper and zinc. | + | In humid temperate regions, the optimum soil pH range for most plants is between 6.0 and 7.5 <ref> Craul, P.J. 1999. Urban Soils: Applications and Practices. John Wiley & Sons, New York.</ref>. More acidic soils inhibit the solubility of potassium, sulfur, calcium, magnesium and molybdenum, while increasing the solubility of iron, manganese, boron, copper and zinc. |