Some Aspects of the Systematics and Diagnostics of Peat Soils of Boreal Mires

Resumo

On the basis of the review of available literature sources, the approaches to the systematics of peat soils in different soil classifications systems (Russian, German, FAO-UNESCO, WRB, and Soil Taxonomy) are discussed and compared with the landscape-based classifications of boreal mires. Among the diagnostic criteria, the most important in the systematics of peat soils and peatlands are the peat thickness, trophic status as the availability of nutrients and as a botanical concept, and acidity (pH) of peat and peat waters. The following suggestions are made: (a) to establish the peat thickness ≥30 cm as a criterion for peat soils, (b) to exclude the contents of nutrients in the peat from the diagnostic scheme for peat soils, and (c) to develop this scheme on the basis of geobotanical indicators. The latter may include active peat-forming plants, as well as plant species settling on the regressive mires under conditions of a cessation or drastic slowdown of peat accumulation. It is also recommended that the type of mesotrophic peat soils should be added to the Russian soil classification system and that the subtype of wet regressive soils should be distinguished within the oligotrophic type of peat soils along with the existing subtype of destructive soils.