The significance of gley features in soils derived from grey parent materials

Detailed observations of gley features in soils derived from grey Upper Greensand rocks have been compared with their moisture regimes as determined by water-levels in dipwells. There was good correlation between the incidence of grey ped face and matrix colours of low chroma, prominent ochreous mottling within the matrix and duration of waterlogging. Careful examination of soil macromorphology can be used, despite inherent greyness, to assess the drainage status and Wetness Class of these soils.
Physical and micromorphological analyses suggest that the wetness of some Upper Greensand soils is due to the combination of low vertical permeability in the underlying rock, and moderate horizontal permeability in the overlying horizons. Such circumstances allow perched water-tables to form in wet weather, sustained by lateral flow when rainfall has ceased.