Comparisons of Human‐influenced and Natural Soils at the San Luis Archaeological Site, Florida

Soil‐human relationships of 10 archaeological test excavations were investigated at the San Luis Archaeological and Historic Site, Tallahassee. San Luis was a Spanish mission and Apalachee Indian village during the 17th century. The oldest dated archaeological soils are known to postdate 1520 (± 80) AD. A detailed topographic survey showed the locations of several 17th century features. Artifact distribution data indicated areas where soil development was affected by deposition of archaeological materials. Soil and archaeological observations were made at each excavation. Morphological features there (such as abrupt, smooth boundaries between layers; abrupt, laterally discontinuous layers; dark matrix colors extending to depths greater than expected; weakly‐developed soils as indicated by the lack of argillic or cambic horizons; and textures high in sand with mixings of clay in lower layers) were interpreted as the result of human activities. Several soil chemical and physical properties in the archaeological and buried soils differed. Total P contents were surprisingly low in the archaeological and buried soils, but extractable P amounts were high. Acidity values did not differ greatly in the archaeological and buried soils. Sand dominated the particlesize fraction in the archaeological soils. Clay contents increased as the buried soils were approached. Several of the soil properties studied in the archaeological and buried soils differed from the naturally occurring Orangeburg soil. Investigations at San Luis offered a rare opportunity in Florida to study anthrogentic soils.