Humus content and second humus horizons in grey forest soils of the Vladimirskoe Opol'e Region (Russia).

摘要

More than 900 samples of grey forest soils were analysed. In the profile of soils containing a second humus horizon (SHH), the highest carbon content (3.0%) was found in the plough layer. Upper layers of SHHs may contain up to 4.6% of carbon. This phenomenon along with weakly manifested microtopography of the soil surface and gradual change in the SHH depth makes it possible to conclude that the role of microtopography in the genesis of soils with the SHH is generally overestimated. The SHH may beconsidered the lower part of the integral natural humus-accumulative layer that has not been affected by tillage.