The possible effect of soluble silicon on the lepidocrocite content of gley soils from England and Bangladesh

SUMMARY Nine different gley profiles from England and Bangladesh were studied; out of these, four English soils contained variable amounts of lepidocrocite. The amounts of lepidocrocite present in various layers of these soils decreased with increasing concentrations of Si(OH)4 in the soil solution. The amount of lepidocrocite formed was negatively correlated (r= -0.78) with the atomic ratios of Si/Fe in the citrate/dithionite extracts. Lepidocrocite was absent from the other five profiles, including three surface water gley soils from Bangladesh. These soils contained relatively large concentrations of Si(OH)4 in soil solution, ranging between 0.7 mm and 1.0 mm. The atomic ratio of Sid/Fed in the citrate/dithionite extracts was higher in these soils. Enborne soil contained maximum amount of citrate/dithionite extracted silicon (2.30 mg g−1) with no X-ray crystalline iron oxides in the profile.