Mathematical modeling of the process of water-soline transport in soils

Abstract

A problem related to the actual problem of the process of water and salt transport in soil is solved in the paper; the review of scientific papers devoted to various aspects and mathematical support of the object under research is given. A mathematical model is proposed in the paper to carry out a complex study, taking into account: the colmatage of soil pores with finely dispersed particles with time; the changes in soil permeability coefficient, fluid loss and filtration coefficient; the changes in the initial porosity and settled mass porosity and an effective numerical algorithm based on the Samarsky-Fryazinov vector scheme with the second order approximation where the differential operators in equations are substituted by finite-difference ones. For the derivation of mathematical model of salt transport it is assumed in the paper that the pressure gradient in the canal is constant and equal to atmospheric pressure. The results of calculations on the proposed algorithms are presented in the form of graphs; a detailed analysis of these results is given. At the end of the paper, conclusions are drawn related to the analysis of numerical computer calculations. It is established that with scarce irrigation, the maximum absorption of water and the accumulated salt transport occurs in the upper layers of soil. Numerical calculations have established that changes in the rate of water transport in soil depend on: porosity, soil permeability, filtration coefficient, composition and structure of soil, and the porosity of settled mass. The process of salinity has reached equilibrium after the use in irrigation of salt water for several years.