Short-term, post-burial change in a humic rendzina soil, overton down experimental earthwork, Wiltshire, England

Abstract

The 1992 excavation of the Overton Down Experimental Earthwork provided a unique opportunity to study pedogenic change in a humic rendzina soil 32 years after burial beneath a chalk bank containing a central stack of turves. Investigations focused on soil structure, porosity, organic matter, plant remains, pH, carbonate, iron, and magnetic susceptibility. Standard methods of chemical analysis and micromorphological description were complemented by quantitative analysis of soil thin sections. The results demonstrate both the speed of change (e.g., compaction and organic decomposition have reduced the thickness of the Ah horizon by >50%c in places), and the way the microenvironment of burial can significantly affect the nature and direction of change (e.g., differences in pH, carbonate, soil structure, and earthworm activity between soils buried beneath the chalk rubble and the central turf stack). These have important implications for the preservation of biological and cultural remains, and for the maintenance of their stratigraphic integrity. © 1996 John Wiley & Sons, Inc.