Post-agrogenic transformation of texture-differentiated soils of the northern forest-steppe near the Irtysh River in the Omsk region

Weak or blind drainage of the territory, changing hydrothermal conditions and water regime, high volumes of lime materials used in the 1990s contributed to carbonate salinization of soils and accumulation of ready soluble salts in the profile of texture-differentiated soils. In sod-podzolics gleyic soil, the maximum amount of carbonates (14.3–17.2%) is accumulated in horizons BT ncg at a depth of 73–104 cm. In grey gleyic soil, their content reached the highest values (14.5–14.8%) in sod (AY dc ) and humic eluvial (AEL dc ) horizons, gradually decreasing to the parent rock. The presence of carbonates shifted the medium reaction to the alkaline interval throughout the entire soil profile. In sod-podzolics gleyic soil, the reaction of the medium was within the range of 6.9–8.1; in the horizons of maximum accumulation of carbonates, it reached 8.5–9.1. In the profile of grey gleyic soil, the pH value varied within the range of 8.1–9.2 units. Ready soluble salts of chlorides and bicarbonates were present at a depth of 61–73 cm, but their content did not exceed 1 mmol/100 g of soil. The morphological structure of the soil profile corresponded to their type affiliation. In the sod-podzolics gleyic soil, eluvial horizon EL was clearly distinguished, in the grey gleyic soil; humus-eluvial AEL horizon was clearly picked.