Base Saturation is an Indication of Soil Fertility
Base Saturation is closely linked to soil fertility. The ease with which adsorbed minerals (cations) are released to plants depends on base saturation.
Percent base saturation (BS) is the percentage of the Cation-Exchange Capacity occupied by the basic cations Calcium, Magnesium and Potassium. The three basic cations are essential minerals that play a key role in plant growth. Basic cations are distinguished from the acid cations like Hydrogen and Aluminium.
At an approximate soil pH 5.4 or less, Aluminium is present in a significantly high concentration that hinders growth of most plant species, and the lower the soil pH, the greater the amount of toxic Aluminium. Most plants prefer soil pH 5.5 and higher.
Soils with a high percent base saturation are generally more fertile because:
1. They have little or no acid cation Aluminium that is toxic to plant growth.
2. Soils with high percent base saturation have a higher pH; therefore, they are more buffered against acid cations from plant roots and soil processes that acidify the soil (nitrification, acid rain, etc.).
3. They contain greater amounts of the essential plant nutrient cations Potassium, Calcium and Magnesium for use by plants.