Transformation of Water Retention and Transport Function of Artificial Soils in Moscow

The results of experiments to study changes in the hydrological properties of soil substrates composing profiles of artificial soils (constructozems) 1–4 years after their creation are presented. Constructozems are represented by two variants, layered soil including Ap horizons, lowland peat and quarry sand of equal thickness, and a mixture of these substrates in an identical amount by weight, as for layered constructozems. Water retention curves obtained by the capillarimetric method on samples with undisturbed structure are compared. A decrease in the water-holding capacity of the peat layer and an increase in the mixture samples are found a year after constructozems had been placed. The laboratory and field experiments have shown a statistically significant difference in moisture filtration rates of the layered constructozem and the mixture. The sharp boundaries between soil horizons contrasting in their properties reduce moisture migration rates to zero values. The obtained breakthrough curves of potassium ions suggest that the continuous pathways of rapid movement of moisture and dissolved substances have formed after 4 years of functioning of artificial soils and are most pronounced in the structures with the homogeneous soil profile.