ترکیب مواد آلی خاک در امتداد شیب در یک چشم انداز آبیاری تحت تاثیر فرسایش در شمال شرقی آلمان

In hummocky landscapes, soil erosion is forming truncated profiles at steep slope positions and colluvial soils in topographic depressions thereby affecting soil organic carbon (SOC) storage. However, the knowledge on the spatial distribution and composition of differently stable organic matter (OM) fractions in arable landscapes is still limited. Here, amount and composition of OM from top- and subsoil horizons at eroded, colluvic, and non-eroded slope positions were compared. The horizons were from a Luvisol at plateau (LV), an eroded Luvisol (eLV) at mid slope (6% slope gradient), a calcaric Regosol (caRG) at steep slope (13%), and a colluvic Regosol (coRG) at hollow position. Water soluble (OM-W) and pyrophosphate soluble (OM-PY) fractions were extracted sequentially. Soil samples, OM fractions, and extraction residues were analyzed with transmission Fourier transform infrared (FTIR) spectroscopy. The soluble fractions were 3% of SOC for OM-W and 15% of SOC for OM-PY. For topsoil samples, extraction rates were independent of slope position. The highest intensities of both, C