14C measurement of soil in post-mining landscapes

Abstract The formation and development of new soil organic matter under extreme soil conditions was investigated in the Lusatian lignite mining district. In order to assess the development of forest ecosystems the pedogenesis (soil development) was studied, especially the contribution of soil organic matter formed during the decomposition of plant residues and the significance of lignite inherent to the parent substrate. To determine the depth gradient of soil organic matter accumulation a differentiation between lignite derived ( 14 C “free”) and recent carbon in the mine spoil was necessary. This was performed by AMS 14 C measurement of the total organic carbon TOC (lignite derived and recent organic matter) of the soil. For TOC extraction a suitable preparation method was used. The calculation for obtaining the soil organic matter and lignite content is discussed and results of different study sites are presented. It is shown that 14 C measurements of soil samples by AMS is a very helpful tool to evaluate the accumulation of recently formed organic carbon and to differentiate this carbon pool from the geogenic, i.e. lignite derived organic carbon supply in post-mining soils.