Soil morphology, genesis, and monolith construction of an acid sulfate soil with silica-cementation in the US Mid-Atlantic Region

Abstract

Soil monoliths are powerful tools for soil education and for representing soils as they are found in the field. They preserve and display major soil features and are portable. The monolith herein described was collected from an active acid sulfate soil located near the western shore of the Chesapeake Bay in the Coastal Plain physiographic province in Maryland, US. The key features of this profile include a silica-cemented layer, a sulfuric horizon, prominent concentrations of jarosite and iron oxide, glauconite, and sulfidic materials. The silica-cemented layer, similar to a duripan, created a challenge for the collection of a soil monolith from this site. This layer was disassembled, fragments were cut to size, and the layer was reassembled in a soil monolith containing the underlying and overlying soil horizons. This appears to be the first published report of a method for creating a soil monolith in a silica-cemented soil. Silica-cementation in acid sulfate soils is rarely reported in the pedologic literature, though cemented layers are occasionally reported in literature on sulfidic mine tailings. By understanding silica-cementation in acid sulfate soils we may be able to induce it as a management practice in mine tailings and other environmentally hazardous sites. The goals of this study are to report on a method for creating soil monoliths from silica-cemented soils, to present explanations for the genesis of this unusual soil, and to highlight how a pedologic study of this soil could lead to further experiments to mitigate some environmentally hazardous sites.