At present, the genesis, nomenclature, and classification of granuzems remain debatable, which is explained by scarce data on these soils. In this paper, data on granuzems described in the forest-tundra of the Norilsk depression, in the valleys of the Tukalanda, Akkit, and Khantaika rivers (68 degrees 30 ' N, 88 degrees 15 ' E) and in the northern taiga within the lower reaches of the Nizhnyaya Tunguska River (66 degrees 20 ' N, 89 degrees 00 ' E) are discussed. Genetic and geographic features of granuzems are closely related to the mineralogy and texture of their parent materials represented by moraine and glaciofluvial loamy and clayey sediments derived from quartz-containing dolerites. Granuzems are characterized by the strongly acid or acid to neutral reaction and, accordingly, by the low base saturation in the upper horizons and moderate base saturation in the lower horizons. Granuzems are characterized by the elevated content of humus of the fulvate composition (C-ha/C-fa < 1) and by the high content of oxalate-extractable iron. The main soil-forming processes are weathering and aggregation of the coagulative cryochemogenic nature. The horizon with strong rounded-grain or crumb-granular structure serves as a diagnostic horizon of granuzems. The surface litter horizon may have different thickness and decomposition degree.
展开▼
