The method of obtaining soil's water-physical properties via their a granulometric composition

Abstract

The method of obtaining water-physical properties of soils (basic hydrophysical characteristics (BHC) and moisture conductivity function) is presented. These properties, or functions, allow us to describe the vertical movement of moisture in unsaturated soils as one of the components of the expenditure item of the water balance. They are widely used in the substantiation of water reclamation and in the modeling of moisture transfer in the soil. The method is based on laboratory studies of soil samples taken in the field on the granulometry composition. The results of laboratory test now in Ukraine are usually obtained by the method of Kaczynski with two components, the percentage of clay and sand. They are graphically, with the help of integral (cumulative) curves are transformed into data corresponding to the international classification - with three components: the content of sand, dust, clay. The latter fractional distribution is used by the world community of soil scientists. Therefore, using data on the content of sand, silt, clay, using a computer program with open access "Rosetta" USDA (United States Department of Agriculture) the water-physical properties in the form of water constants: the saturated soil moisture, the residual soil moisture, the saturated hydraulic conductivity, and the coefficients of the equations of the mathematical model of van Genuchten are calculated. The publication provides examples of calculation of water-physical properties of soils by the presented method of dark chestnut soils and ordinary chernozems. The advantages of the proposed method include the low complexity of experimental studies, the availability of analyzes and the presence of many experimental studies of the granulometry composition of soils, including in literary sources. As a development of the research direction, the author shows the application of the obtained dependence for modeling moisture transfer during water reclamation (irrigation in irrigation control systems.). Regarding the directions of future research, the publication recommends comparing the accuracy of obtaining water-physical properties of soils by different methods, as well as obtaining an important water constant - the field capacity (FC) as the lowest field moisture content.