Vertical Moisture Transfer Investigation on Lysimeters Taking into Account Substrates Granulometric Heterogeneity

Abstract

The issues of soil-hydrophysical support of mathematical models of moisture movement, taking into account the heterogeneity of the soil, due to the spatial change in texture, are considered. The processes of vertical movement of moisture on large-sized lysimeters of the Federal Scientific Center of Agroecology of the Russian Academy of Sciences (Volgograd) were studied. The influence of statistical heterogeneity of hydrophysical parameters of lysimeter substrates was studied on models of moisture transfer dynamics and formation of gravity flow developed in the environment of the HYDRUS-1D software package. The change in texture along the vertical profile of the lysimeters and the related variability of the main hydrophysical characteristic (WRC) were taken into account. The granulometric heterogeneity of the substrates was estimated by the scaling method, according to the scale factors of the WRC parameters, assuming a normal probability distribution of the logarithms of the pore space capillary radii between soil particles. The effect of texture on water-holding capacity, boundary and initial conditions, intensity of gravity runoff and cumulative accumulation of moisture was studied.