Trace elements in Finnish soils as related to soil texture and organic matter content

A study was conducted to evaluate the relation of the total contents of Co, Cu, Mn, Ni, Pb and Zn on soil texture and organic matter content. In spite of a wide variation, a clear tendency for the trace element contents (Pb being an exception) to decrease with increasing particle size was found. The reason for this is believed to be associated with the geological origin of the soil material and with the relative resistance to weathering of the minerals from which the trace elements are derived. In mineral soils the contents of trace elements increased with increasing organic matter and the maximum contents are likely to be found in soils containing from 5 to 15 per cent organic matter. A further increase in organic matter tends to decrease the total contents of trace elements expressed on a volume basis (kg/ha). The causes underlying this relation, which are believed to be pedological rather than chemical, are discussed