What relationship exists between pH and base saturation of soil?

The relationship between pH and base saturation in soil is such that as pH increases, base saturation also tends to increase. Base saturation refers to the proportion of soil cation exchange capacity that is occupied by base cations such as calcium, magnesium, potassium, and sodium, rather than acidic cations like hydrogen and aluminum.

In acidic soils, which have lower pH values, there tends to be a higher presence of hydrogen ions that can contribute to soil acidity, thus reducing base saturation. As the pH increases, indicating a more alkaline environment, the proportion of base cations in the soil generally increases. This is because the availability of essential nutrients is enhanced in higher pH conditions, allowing for greater saturation with base cations and ultimately improving soil health and fertility.

Therefore, the correct answer reflects the positive correlation between increasing pH levels and an increase in base saturation, which is crucial for understanding soil chemistry and nutrient management practices.