In contrast, phosphorus may become limiting in acid soils. Also, in acid soils, aluminum can become available. It is not a nutrient and is toxic to plants in high concentrations. At pH 6 and higher, very little aluminum is in solution. Additionally, soil pH affects the abundance of microorganisms.
Bacteria are generally more prevalent in alkaline soils and fungi dominate in acidic soils.
This is important because microbes are responsible for the cycling of nutrients. The most diverse and numerous populations are found in near-neutral soils. Furthermore, soil pH influences pathogenic microbes, and growers can adjust pH to manage some plant diseases. High pH values may also lead to nutritional problems. Acidic soils may be neutralized over time with the application of lime.