Assessing the Role of Soil Chemical and Physical Characteristics On Stone Deterioration At Cultural Heritage Sites: Soft Capping of Ruins in England.

Research on soils in the context of archaeology and cultural heritage conservation is extremely limited compared to research of soils in agriculture, ecosystems, and landscapes, and is often carried out with minimal consideration of soil science methods or perspectives; the same proves true with the dissemination of results.  This research aims to investigate, from a soil science perspective, whether soils used to protect cultural stone through the method of soft capping are benign or likely to cause alteration to the stones due to the environment they facilitate.  Soft capping is being trialed on numerous cultural heritage ruin sites throughout England, and is of interest to cultural heritage site managers worldwide.  Soft wall caps are composed of a thin soil layer (5-10 cm thick), with a covering of turf that is laid upon wall heads to limit moisture infiltration and mediate thermal differentials in the stone.  Previous research reveals it is effective in both cases.  However, no work has been done to evaluate soil chemical and physical characteristics and conditions within the soft caps.

Soft capping was examined at Wytham Woods in Oxford; Godstow Nunnery, a medieval 12^th century ruin in Oxford; and Hailes Abbey, a large medieval 13^th century Cistercian abbey ruin in Gloucestershire.  Soft capping soil type is loam and vegetation cover types include local turf, commercial turf, sedum mat, and seeded mat.  Soft capping ages range from less than one year to approximately thirty years old.  In situ soil moisture, temperature, pH, and EC measurements were monitored regularly with handheld probes and emplaced sensors.  Seasonal soil samples were taken for chemical and physical analysis, and preliminary results of theses analyses will be presented and discussed to evaluate soil chemical and physical characteristics of, and conditions in, soft capping and whether they favor preservation or alteration of cultural stone.