The discrepancy between 14C and OSL dates of Celtic field banks and the high values for Secale in these banks in Denmark, Germany and the Netherlands calls for an explanation. This article shows that downward movement of pollen must have caused this discrepancy. It also means that it will not be possible to get an impression of the cultivation of the Celtic fields in the Iron Age-Early Roman period by pollen analysis of these soils, because the pollen evidence from this period is overshadowed by the Early Medieval data. Only the old surface layers underneath the banks, sometimes with traces of early/pre-Celtic field cultivation, may provide some information concerning that period. However, in some cases this picture is also disturbed by the penetration of younger pollen.
The Early Medieval pollen data from the banks point to summer rye cultivation taking place on the banks, in accordance with high phosphate values, particularly in the top layers of the banks.