Zonal features of humus formation in Al-Fe-humus podzols of the Kola Peninsula

Natural zonality manifests itself clearly in the territory of the Kola Peninsula: subzones of southern tundra, forest-tundra (sparse birch forest), and northern taiga replace one other from the north, to the Barents Sea coast, and to the south. Sandy and sandy loamy sediments of glacial, marine, and glaciofluvial origin are parent rocks all over the territory. Al-Fe-humus podzols, the profile of which is characterized by clear differentiation of the chemical composition and organic matter content, were formed on these rocks. There is almost no difference in the particle-size and total chemical composition of the podzols, whereas the content and composition of the humus in the soils of different zones differ significantly, and this is especially obvious in the illuvial horizon. As the climatic severity increases, the humus content in the mineral profile and the organic matter enrichment with nitrogen increase.