The influence of long-term tillage on agrophysical properties of dark gray forest soils of forest-steppe zone of Trans-Urals

The changes in the properties of dark gray forest soil (Luvic Retic Greyzemic Phaeozems (WRB, 2014)) on the territory of the forest-steppe zone of the Trans-Urals under the influence of long-term agricultural use during annual dump processing were studied. On the basis of field and laboratory studies, anthropogenic changes in agrophysical properties in the soil profile of arable dark gray forest soils were identified. The dynamics of agrophysical properties of arable and virgin dark gray forest soil covering a 50-year period (1964-2018) was analyzed. It was established that in natural state, dark gray forest soils of the forest-steppe zone of the Trans-Urals were characterized by gradual improvement of agrophysical properties. The annual dump system of main processing contributed to the increase in the process of illuviation. Medium and fine dusts, as well as the silty fraction were subject to migration. It was found that in arable horizon of dark gray forest soils, the content of physical clay decreased by 6.5-7.6 % over 54 years, and silty particles - by 5.1-17.0 %. The accumulation of medium and fine dust was recorded directly under the arable horizon. Elementary soil particles with a size less than 0.001 mm migrate to the depth of 60-80 cm. Impoverishment of the arable layer by the silty fraction led to the decrease in the water strength of soil aggregates and the increase in the density of addition in the layer of 30-50 cm to 1.45 g/cm3. As a result of long-term use of the dump processing system, the lowest water capacity in the 0-50 cm layer corresponded to 162 mm, while on arable land - 186 mm.