Neolithic formation of chernozem in south-eastern Germany?

Abstract

The polygenetic development and age of black soils and Chernozems in Central Europe are widely discussed. The development and age of these soils in Germany is still not fully understood. While a significant share of Chernozems in Central Germany is assumed to have formed naturally during the early Holocene, such a natural formation can be excluded for all of southern Germany for paleoclimatic and –vegetative reasons. Therefore, soils with chernic horizons of natural origin are not to be expected south of the central German uplands. Active soil alteration by the human population in the Neolithic has also been observed to lead to Chernozem-like soils in other regions of Germany, like Lower Saxony and North Rhine-Westphalia. The unexpected black horizon investigated in this study is located close to Straubing in Bavaria, southeast Germany. The prevailing natural soil type in the area is a calcic Luvisol on loess substrate. The black horizon is located in close proximity to a neolithic settlement and its graveyard. We hypothesise that the inhabitants of the nearby neolithic settlement used the area with the black horizon as an agricultural field and were managing it actively. The core area with the most pronounced black horizon is rectangular and comprises within the excavation a surface of ca. 0.83 ha. Several decimetres of Holocene colluvium buried the black horizon in the Late Bronze Age and subsequent periods (OSL and 14C-Dating). Dating results from the black horizon prove human impact on the soil starting in the Linearbandkeramik (LBK) period (cal BC 5,209–4,911, 14C-Dating). NMR- and FTIR-DRIFT-analysis show high contents of pyrogenic carbon in the black horizon, which is responsible for its dark colour, even though the mean share of carbon is not higher than 0.50 ± 0.03 % (mean ± se). These results match those of recent literature and, therefore, indicate that neolithic farmers also applied their targeted soil amendment practices in southern Germany. This follows archaeological findings on the colonization of the area by the neolithic settlers: Primordially coming from the Fertile Crescent (northern Middle East), they followed the Danube through the Pannonian Region and brought their agronomic knowledge from the prior settlement area, where their active soil management is archaeologically proven.