Chemical Properties of Acid-Sulfate Soils Recently Reclaimed from Florida Marshland
1973
Calvert, D. V. | Ford, H. W.
Acid soil layers, with pH as low as 3.0, were found in the subsurface horizons of soils derived from marine sediments and have been recently developed into citrus groves. Soil layers with acidity varying from pH 3.0 to 7.7 and sulfate content from 0.5 to 39.0 meq/100 g of soil were compared for their capability of producing acid-sulfates. Lime requirements of selected acid layers were found to be as high as 4.5 meq of CaCO₃ equivalent per 100 g of soil. The acid-sulfate potential (oxidation of reduced sulfur to H₂SO₄) accounts for the reduction of pH of the reclaimed soils. The sulfate content of soil layers was often in excess of 2,000 ppm when the soil pH after oxidation with H₂O₂ was below 3.0 and was dependent on oxidizable sulfur content of the sample and buffering capacity of the soil. Oxidized soil layers with pH values below 3.5 released soluble Al and Fe up to 275 ppm and 100 ppm, respectively.
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