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gleyed topsoil, the portion of the soil profile characterized by lack of structure, low porosity, and green, blue, dove-gray, or mixed dove-gray-red color. It is formed as a result of the gleying of soils, a complex set of processes predominantly microbiological and biochemical in nature, including reduction of mineral and organic substances with formation of unstable forms of oxides of iron, manganese, aluminum, and other elements accumulated in the soil; transformation of humic acids into fulvic acids; acidification of the soil reaction with entry into the absorbing complex of bivalent iron, hydrogen, and aluminum; destruction of alumosilicate minerals with neogenesis of clay minerals containing bivalent iron; and a number of other phenomena. It develops in various swamped and marshy soils in topsoils with difficult or no access to oxygen (under the influence of ground or surface waters). Gley exerts an adverse effect on the overwhelming majority of wild and cultivated plants. Reclamation of gleyed soils involves first of all drying them out—lowering the level of groundwater and eliminating excess surface waters. The term “gley” was first introduced into scientific literature by the Russian scientist G. N. Vysotskii (1905) and became international in soil science.
V. M. FRIDLAND