Diversity of humus stocks in the arable soils of the Late Pleistocene ground morains in Mecklenburg, West Pomerania, Germany

Abstract

Local humus stocks (= contents of soil organic matter, SOM in kg · m⁻²) of arable soils were investigated in several regions of the seemingly uniform ground moraine-landscape. Depending on relief position, quantifiable effects of humus removal or enrichment are evident, caused by denudation or colluviation. The depth (thickness) of the investigated humus-bearing topsoil horizons varies between 15 and 150 cm overall and amounts on average to 67 cm. Extreme values of SOM (resp. C_org) stocks are 2.73 (1.58) and 137.41 (79.70) kg · m⁻². The average values of all found SOM (resp. C_org) stocks in the investigated arable soils amount to 10.78 (6.25) kg · m⁻². Humus stocks are not only of importance for the agricultural yield potential but also because of their function as a sink for, or a source of, atmospheric CO₂, which is of special current interest due to its influence on menacing climate change. The total carbon content of the corresponding column of atmosphere, 1.60 kg · m⁻², amounts to only one quarter of the average in our arable soils.

Keywords:

• Humus stocks
• effects of relief position
• soil fertility
• influence on climate

Acknowledgements

Thanks to Martin Heimann, Max-Planck-Institute for Biochemistry, Jena, for calculating the C stock of the atmosphere comparable with the soil. Thanks also to Jörg Rinklebe, University of Wuppertal, for helpful information.