Usually called Calcareous? Or should it be called Carbonateceous soils? Is Gypsum Needed for a carbonate dominated soil Read on.
Soil pH or the “acidity” or lack of acidity of a soil can be confused by the different uses and chemistries that surround the term pH, or the power of hydrogen. This can be further confused by the terms “alkalinity” or “basicity” of the soil or the soil solution which can further confuse the situation by whether the solid or liquid phase of the soil is being measured. So, in short, a soil is acid if it has a pH below 7 (more hydrogen ions) and basic when above 7 (fewer hydrogen ions). Big numbers are more basic, small numbers more acidic.
The natural world has a pH scale of 1 to 14. Knowing soil pH is important because it can tell you the inherent fertility of a soil. Usually the higher the number between 5 and 8, the more “basic” nutrients are present, like calcium, magnesium and potassium. When the numbers get lower than 5 and larger than 8, the nutrients may not be there or they may be tied up. Changing the pH can often release nutrients that are not available. Iron and zinc plant deficiencies are most often controlled by soil pH and once pH is neutralized or made acid, the deficiency disappears. In a way, pH is one of the most important nutrient indicators of a soil's fertility and managing should be an essential practice.