5β-Stigmastanol and Related 5β-Stanols as Biomarkers of Manuring: Analysis of Modern Experimental Material and Assessment of the Archaeological Potential

A modern experimental agricultural site was used to assess the possibility of using lipids as biomarkers of manuring in archaeological survey work. The modern experimental material originated from the Butser Ancient Farm site in Hampshire, U.K., where a plot under wheat cultivation had been subjected to manuring over half of its area for 13 years. A series of samples, including fresh dung, manure, and soil from manured, non-manured and control areas, was analysed in order to establish whether the application of manure results in enhanced biomarker abundance, specifically of 5β-stanols. Biomarker analysis involved extraction of total lipid from soil samples, fractionation by thin layer chromatography, and analysis by gas chromatography and gas chromatography/mass spectrometry using selected ion monitoring. A distinct enhancement of the specific 5β-stanol markers characteristic of cattle faeces/manure was found in the manured area when compared to the non-manured and control areas. The method thus holds considerable potential for archaeological application. The results from the biomarker analysis are compared to those from magnetic susceptibility measurement, total lipid and organic elemental C, H, and N analyses, and a range of inorganic elements. These comparisons served to highlight the potential advantages of the biomarker approach based on the 5β-stanols.