Soils in the south Florida flatwoods are underlain by calcium carbonate (CaCO3) that has accumulated through marine deposition over thousands of years. In most flatwoods, the CaCO3 lies below the profile and the overlying surface soil is usually acidic. However, CaCO3 also can occur at the surface, either naturally or as a result of earth-moving operations that have mixed the soil. The resultant soil is called calcareous. Soils also can become calcareous through long-term irrigation with water from the Floridan aquifer. This water contains small amounts of dissolved CaCO3 that can accumulate with time.

Florida calcareous soils are alkaline (have pH values greater than 7) because of the presence of calcium carbonate (CaCO3), which dominates their chemistries. These soils can contain from about 3% to more than 25% CaCO3 by weight, with pH values in the range of 7.6 to 8.3. Usually, the pH is not in excess of 8.3 regardless of CaCO3 concentration, unless a significant quantity of sodium (Na) is present.

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Authors | Source:

Thomas A. Obreza, Ashok K. Alva, and David V. Calvert
https://ucanr.edu