On the Challenges of Soil Phosphorus Prospections in Heterogeneous Environments—a Case Study on the Iron Age Altenburg Hillfort (Niedenstein, Hesse, Germany)

Abstract

AbstractHeterogeneous environments might be considered inadequate for geoarchaeological soil phosphorus (P) prospections due to the manifold potential alterations of archaeologically relevant soil P contents. To elucidate if this assumption is correct, we conducted a case study in the heterogeneous environment of the Iron Age Altenburg hillfort near Niedenstein (Hesse, Germany). We introduce the least influenced area (LIA) approach to deduce the native soil P contents of the local soils inductively from own soil P data. The native P contents are crucial for further data evaluation in any P prospection. Moreover, we develop two parameters to quantify and compare soil P enrichment in pedogenically heterogeneous areas: the mean enrichment ratio (MER) and the maximum enrichment ratio (XER). Finally, we modify and discuss the approach of Lorch (The Science of Nature 28(40/41):633–640, 1940) to interpret spatial patterns of soil P enrichment with regard to prehistoric land use. Our study shows that soil P prospections can be conducted in heterogeneous environments. Still, they require a systematic field work strategy and soil scientific support. Moreover, instead of absolute soil P contents, alternative parameters must be derived from the data to evaluate soil P enrichment adequately for a heterogeneous area. Using such alternative parameters on the basis of our data, the Iron Age Altenburg hillfort was significantly larger than formerly assumed. Only the Altenburg plateau and the directly adjacent slopes seem to have been densely covered with buildings. The neighboring areas might have been used for different purposes including agriculture, livestock grazing, and economic activities.