Landscapes of loessial islands in high Novgorod-Siversky Polissia

Abstract

The territory of Novgorod-Siversky Polissia is characterized by natural conditions as a province of mixed forests, where soddy-podzolic soils of low fertility have formed on loamy sandy and sandy deposits. However, on the high plateau the Desna River valley right bank, there are Novgorod-Siversky and Ponornitsky loessial islands with fertile dark-colored soils (Opillia). They were formed in rather damp and cool conditions, which is natural for the forest zone. However, their landscapes by the property of the components have a forest-steppe nature. On the plateau, in the Novgorod-Siversky Opillia, eolian loessial is located, which led to the formation of dark gray podzolized soils and chernozems leached and podzolized mainly with a humus-degraded arable layer. On sufficiently large areas near localities Pontornytsya, Pokoshychi and Desnianske there was happened loessivation and silt-loam sandy. Fertile gray forest soils were formed here – a kind of Opillia region. During the large-scale survey and mapping of Ukraine's soils in 1957–1961, dark-colored soils of loessial islands were defined predominantly as dark gray podzolized. However, our recent studies have proved the widespread distribution of leached chernozems and podzolized opіlsky chernozems. On strongly eroded slopes of the right-bank native shores, we have remnants of the suboak forest, which indicate the forest-steppe nature of the landscapes. In virgin areas, unlike sandy areas, a thick bean-grass-mixed grass cover, including indicators of forest-steppe. The Opillia area with chernozems and other dark-colored soils is a major agrarian resource of the region. But gray forest soils also belong to the most valuable land in Polissia. On gray forest soils, cereal crops are grown by 4–5 centners per hectare higher than those on typical of the Polissia sod-podzolic soils. Loessial islands are common in southern part of Novgorod-Siversky Polissia, in particular, on the Desna River valley right bank. Landscapes are diverse in properties of components – the nature of loessial species, geological foundations, features of soil cover and relief. They are united by forest-steppe features of soil cover, the presence in the central part of Opilia – fertile dark-colored soils, including chernozems with signs of relic steppe phase in their development, meadow-steppe composition of herbaceous cover on virgin areas and the presence of remnants of the suboak forest. These are large fragments of the Forest-Steppe in Polissia, which have a high natural resource.