2.2.2. Laboratory analyses and SOC stock calculations
Soil organic carbon content (SOC %) was determined using a LECO CNS elementary analyzer. The calibration method was based on ISO 10694:2002 and was three-point calibration with the transition through point 0. C: y = 0.9904x + 0.0051. Mean SOC (mass %) was calculated for the sampled soil horizons. SOC content in the CDs (SOC cont, t) was calculated using the volume (V, m³) of colluvial layers and fossil soil horizons as well as bulk density (B, t·m³). The volume (V, m³) of colluvial layers and fossil soil horizons was determined as the product of the areal extent (E, m²) of the colluvial layers and the fossil soil horizons and the mean thickness (D, m) of these layers : V = E x D;
SOC cont = V x B x SOC (%).
SOC content in the soil covering the loess plateau and slopes in the studied region was estimated using data from soil profiles studied by Paluszek (2001) and Paluszek, Żembrowski (2008).