Transformation of the properties of soddy-podzolic soils under the impact of drainage and cultivation

The results of long-term stationary studies of the properties of loamy soddy-podzolic soils under forest vegetation and cropland are considered. Spatial and temporal changes in the morphology and physicochemical properties of the soils under the impact of long-term plowing are analyzed. It is shown that the soil profile becomes homogenized under the impact of regular tillage operations; at the same time, the features of gleyzation become more pronounced. The plowed soils are characterized by less active removal of clay and the main oxides from the eluvial layer. The thickness of the zone of active eluviation in these soils is lower than that in their virgin analogues. At the same time, the illuvial accumulation of sesquioxides and magnesium takes place in the Bt horizons of the plowed soddy-podzolic soils; the thickness of the zone with the maximum concentration of iron nodules gradually increases. These facts attest to a predominance of vertical water fluxes in the profile of the plowed soils. The long-term agricultural use of these soils has led to a general increase in the reserves of humus and leveling of the soil humus content along the catena. The soil drainage resulted in the appearance of linear zones (along the drains) with sharp contrasts in the morphology and physical and chemical properties of the plow layer. In particular, the soil humus content somewhat decreased, whereas the degree of soil heterogeneity increased under the impact of drainage.