title: Organic fertilization and sufficient nutrient status in prehistoric agriculture?--Indications from multi-proxy analyses of archaeological topsoil relicts.
abstract: Neolithic and Bronze Age topsoil relicts revealed enhanced extractable phosphorus (P) and plant available inorganic P fractions, thus raising the question whether there was targeted soil amelioration in prehistoric times. This study aimed (i) at assessing the overall nutrient status and the soil organic matter content of these arable topsoil relicts, and (ii) at tracing ancient soil fertilizing practices by respective stable isotope and biomarker analyses. Prehistoric arable topsoils were preserved in archaeological pit fillings, whereas adjacent subsoils served as controls. One Early Weichselian humic zone represented the soil status before the introduction of agriculture. Recent topsoils served as an additional reference. The applied multi-proxy approach comprised total P and micronutrient contents, stable N isotope ratios, amino acid, steroid, and black carbon analyses as well as soil color measurements. Total contents of P and selected micronutrients (I, Cu, Mn, Mo, Se, Zn) of the arable soil relicts were above the limits for which nutrient deficiencies could be assumed. All pit fillings exhibited elevated δ15N values close to those of recent topsoils (δ15N>6 to 7‰), giving first hints for prehistoric organic N-input. Ancient legume cultivation as a potential source for N input could not be verified by means of amino acid analysis. In contrast, bile acids as markers for faecal input exhibited larger concentrations in the pit fillings compared with the reference and control soils indicating faeces (i.e. manure) input to Neolithic arable topsoils. Also black carbon contents were elevated, amounting up to 38% of soil organic carbon, therewith explaining the dark soil color in the pit fillings and pointing to inputs of burned biomass. The combination of different geochemical analyses revealed a sufficient nutrient status of prehistoric arable soils, as well as signs of amelioration (inputs of organic material like charcoal and faeces-containing manure).
authors.affiliation: Institute of Crop Science and Resource Conservation - Soil Science and Soil Ecology, University of Bonn, Bonn, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Lauer
authors.affiliation: Institute of Crop Science and Resource Conservation - Soil Science and Soil Ecology, University of Bonn, Bonn, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Prost
authors.affiliation: Archaeological Heritage Management Rhineland (LVR-Amt für Bodendenkmalpflege im Rheinland), Bonn, Germany.
authors.forename: Renate
authors.initials: R
authors.lastname: Gerlach
authors.affiliation: Institute of Crop Science and Resource Conservation - Soil Science and Soil Ecology, University of Bonn, Bonn, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Pätzold
authors.affiliation: Institute of Crop Science and Resource Conservation - Soil Science and Soil Ecology, University of Bonn, Bonn, Germany.
authors.forename: Mareike
authors.initials: M
authors.lastname: Wolf
authors.affiliation: Institute of Crop Science and Resource Conservation - Soil Science and Soil Ecology, University of Bonn, Bonn, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Urmersbach
authors.affiliation: Institute of Crop Science and Resource Conservation - Soil Science and Soil Ecology, University of Bonn, Bonn, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Lehndorff
authors.affiliation: Institute of Crop Science and Resource Conservation - Soil Science and Soil Ecology, University of Bonn, Bonn, Germany; Department of Geography, RWTH Aachen University, Aachen, Germany.
authors.forename: Eileen
authors.initials: E
authors.lastname: Eckmeier
authors.affiliation: Institute of Crop Science and Resource Conservation - Soil Science and Soil Ecology, University of Bonn, Bonn, Germany.
authors.forename: Wulf
authors.initials: W
authors.lastname: Amelung
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001106:Archaeology / Q000266:history*; D001647:Bile Acids and Salts / Q000032:analysis; D002244:Carbon / Q000032:analysis; D005243:Feces / Q000737:chemistry; D005308:Fertilizers; D005390:Fires; D005858:Germany; D049690:History, Ancient; D009584:Nitrogen / Q000032:analysis*; D009587:Nitrogen Isotopes; D058871:Organic Agriculture / Q000266:history*; D010758:Phosphorus / Q000032:analysis*; D012987:Soil / Q000737:chemistry*; D013261:Sterols / Q000032:analysis
chemical_list: D000596:Amino Acids; D001647:Bile Acids and Salts; D005308:Fertilizers; D009587:Nitrogen Isotopes; D012987:Soil; D013261:Sterols; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen