Зміна гранулометричного складу осушених ґрунтів Малого Полісся в контексті розвитку деградаційних процесів

Abstract

Sod-podzolic (Albenuvisoils Gleyic), meadow (Gleyic Chernic Phaeozems) and sod (Arenosols) soils are typical for Male Polissia. In the natural state, these soils are waterlogged, characterized by unsatisfactory physical properties, unsuitable for agricultural use. After the drainage reclamation, the soils are intensively used as arable land, pastures, and hayfields. The drainage has led to a significant decrease in groundwater levels, increased the washing water regime, intensified the processes of lessivage, which affected the physical properties of soils, in particular, granulometric composition. In the reclaimed areas, aridification and deflationary processes intensified. In deflated sod-podzolic soils, the relief of granulometric composition has been reducing due to decrease in the content of sludge and fine dust in the arable horizons. Granulometric composition of soils undergoes more significant transformations as a result of the intensification of flushing water regime after drainage. The content of physical clay in the arable horizon of sod-podzolic fixed- sandy soils decreased by 1.63 %, and of the sandy loam soils – by 5.30–6.20 %. In the humus-accumulating arable horizon of meadow soils, the physical clay content decreased by 2.40–1.60 %, that of sod soils – by 1.27–6.39 %. Washing off with drainage waters of small granulometric fractions results in an increase in the content of sand fractions and facilitates the granulometric composition of soils, changes in soil gradation at the level of variety. Decrease in the content of physical clay causes deterioration of physical, physical-and-chemical, agronomic properties of soils, and therefore causes the development of degradation processes: non-structural, deflation, dehumification, degradation of water and air and nutrient regimes, aridification. This gave rise to the idea of referring to the granulometric composition facilitation of drained soils as “granulometric degradation” and classifying it as physical degradation of soils. Key words: Male Polissia, drainage reclamation, soils, granulometric composition, physical clay, granulometric degradation.