Estimating some hydrophysical properties of soil using mathematical modeling

¹ Peter the Great St.Petersburg Polytechnic University, Polytechnicheskaya, 29, St. Petersburg, 195251, Russia
² Leibniz-Centre for Agricultural Landscape Research, Eberswalder Straße 84, Müncheberg, 15374, Germany
³ Agrophysical Research Institute, Grazhdanskii pr., 14, St. Petersburg, 195220, Russia
⁴ St.Petersburg State Agrarian University, Peterburgskoye shosse, 2, St. Petersburg-Pushkin, 196601, Russia
⁵ V.I.Vernadsky Crimean Federal University, Vernadskogo pr., 4, Crimea, Simferopol, 295007, Russia
⁶ Federal State Budget Scientific Institution «Research Institute of Agriculture of Crimea», Kievskaya, 150,Crimea, Simferopol, 295453, Russia

^* Corresponding author: coolhabit@yandex.ru

Abstract

At substantiating land amelioration and land management designs, as well as during periods of operation and reconstruction of water facilities, information support plays an important role in relation to the hydrophysical properties of soil. Effective implementation of this support faces a number of challenges. Such problems include the very high laboriousness of carrying out the corresponding engineering surveys and laboratory studies. In this regard, the methods of indirect estimating the hydrophysical properties, the measurement of which requires considerable labor, are very in demand for land amelioration and land management practices. An equally acute problem is the problem of the functional representation of the coefficients of the Richards equation, which is widely used in engineering-hydrological calculations. The paper suggests: 1) the original method for assessment of the ratio of the values of the hydraulic conductivity function of soil to the moisture filtration coefficient using data from direct measurements of the water-retention capacity of soil carried out according to the standard procedure; 2) the mathematical model describing the hydrophysical properties of soil, and the system of functions with interpreted parameters that physically adequately describe the coefficients of the Richards equation. In carrying out the study, data on soils of different texture were used. A sufficiently low error in the dot approximation (fitting-procedure) of the experimental data confirms the physical adequacy of the proposed system that includes the functions describing the coefficients of the Richards equation.