The morphology and genesis of eight surface‐water gley soils developed in till in England and Wales

Abstract

The morphology is described of eight surface-water gley soils developed in till in Wales and central and northern England. Physical and chemical analyses as well as micromorphological observations are used to investigate processes affecting the genesis of the soils.The characteristic property of surface-water gley soils, namely slowly permeable subsurface horizons, causes a degree of periodic waterlogging within the profile. Effects of gleying and shrink/swell processes are described.Three main aspects of weathering are shown to be operating: decalcification in two of the three calcareous profiles, the breakdown of coarse into finer particles and the alteration of the clay fraction, chiefly the formation of mixed-layer minerals from mica.Argillic B horizons are present in some soils. In profiles developed in calcareous till the degree of decalcification relates strongly to the amounts of recognizable clay concentrations as seen in thin section. Of the other five profiles three clearly have argillic B horizons. Problems associated with the identification of argillic B horizons in surface-water gley soils in till are discussed.

Phosphorus in macropore walls of a Danish Glossudalf

“…Pseudogleys or surface water gley soils are often characterized by tonguing and interfingering of albic soil material at the ped faces adjacent to macropore walls mainly in the upper part of argillic horizons (Blume, 1968;Murphy, 1984). In many cases strongly pseudogleyed horizons can be classified as glossic horizons (Soil Survey Staff, 1994).…”

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

“…In some places there was evidence that the soils were freely drained whereas in others there appeared to be drainage problems, though there were few signs of ochreous mottles. The grey matrix colour of the soils hinders the recognition of any iron-depleted grey ped faces (Loveland, 1978), a feature recognized as a sensitive guide to the occurrence of waterlogging in pedal soils (Bloomfield, 1951;Avery, 1980;Murphy, 1984). The small iron content appears to limit the mobilization and segregation of iron oxides and hydroxides, which are also diagnostic of periodic waterlogging (Veneman et al, 1976;Avery, 1980).…”