ИСТИНА

Recent research on Volga and Don deltaic sediments posed a question on the possibility of regarding them as soils with discernible diagnostic horizons in the same way as it is done for terrestrial soils. This approach is in agreement with the International soil classification; it was first proposed by the famous soil scientist W.Kubiena, and is supported by studies of American, Dutch, and Russian pedologists. Following Russian tradition of soil nomenclature, the subaquatic bodies received an oxуmoron name AQUAZEMS. They occur in deltaic near-shore zone and lagoons, fresh-water bays, oxbow lakes, with the water layer above them not exceeding 2 m. Aquazems are studied by augering, and in the core obtained, the layers – horizons are specified by color, texture, boundaries, consistence, plant residues, shell debris, and thickness, which is far less than in terrestrial soils (first centimeters); most common are the aquagley and aquahumus horizons. The latter is mostly formed by residues of rooted plants – lotus and reed with additions or losses of Corg-enriched solids transported by currents and tides. The aquagley horizon resembles that of terrestrial soils, and may also have oxymorphic features. The effects of soil-forming agents (relief, parent rock, living organisms) are similar to those for terrestrial soils, although climate is cool and even, age is small, and there is an additional specific agent – currents, modifying the surface and controlling matter transfer. Perception of the study objects as soils is helpful for assessing their environmental functions.