Thermodynamic system of soil, its homeostasis, and probable mechanism of structure formation

Abstract

Goal. To substantiate the dynamic functional model of the thermodynamic system of the soil in interaction with cyclic environmental factors, to disclose internal homeostatic processes, the result of which is the reproduction of the soil structure. Methods. System analysis, theoretical — to generalize the specifics of soil structure and create its physical model; experimental — for laboratory research. Results. Laboratory hydrophysical tests of soil samples of the intact structure revealed the occurrence of hysteresis of water holding capacity of the soil, the value of which can reach 10-20%. The main reason for this phenomenon is the compression of air by liquid membranes in the pore space. The results of the influence of heating the soil sample of constant moisture saturation are presented, which fix the self-oscillating character of the dynamics of capillary potential in the soil. That testifies to the intra-porous redistribution of moisture and the local transport mechanism of convective transport of the matter. Conclusions. The interaction of soil with thermodynamic environmental factors transforms it into a micro gradient dissipative structure with the emergence of many subordinate processes. The main results of their action are the periodic increase of local thermodynamic availability of nutrition for plants and the formation of non-uniform in space cementation of dispersed particles, which become the nuclei of structural units. The concept of soil homeostasis, combining subordination processes, characterizes the level of energy consumption of the external energy flow, due to which the basic properties and structural organization of the soil are reproduced.