Energy entropy analysis of light chestnut soils

Entropy as a process studied in natural phenomena is related to thermodynamics. In particular, when studying the state of the soil, its change is observed, passing through a state of equilibrium. Equilibrium states in the environment are associated with a maximum of total entropy.

The purpose of the research is to determine the energy contained in the soil at various levels depending on the fractional composition of soil particles based on empirical and calculated data.

Novelty. For the first time, an energy entropy analysis was performed for irrigated light chestnut soils, which makes it possible to determine the residual energy stored in the soil.

Materials and methods. According to field data, the analysis of the complete granulometric composition of the soil was carried out with the determination of the weight contribution of each fraction. Calculations based on the results of chemical analysis were used to isolate the mineralogical composition of the soil. The presence of humus and plant residues was determined by a generally accepted method. The sampling was carried out on the territory of the village. The waterway of the Volga-Don interfluve.

Research results. The research presents the characteristics of light chestnut heavy loamy soil. The content of physical clay in the arable horizon (2-25 cm) is 45.2%. The illuvial horizons B1 and B2 are clearly expressed in terms of silt content. The silty fraction of 27.74 - 31.22% prevails. Thermodynamic characteristics enthalpy, Gibbs energy and entropy are not absolute values. They represent the proportion of energy remaining in the soil of a particular mineral, or its property. The analysis of thermodynamic parameters showed that in the horizon of 2-25 cm the values (∆H, ∆G, ∆S) are greatest in the coarse–powdered fraction, followed by the silty fraction, fine- , medium-powdered and sand. At a depth of 26-55 cm, coarse-dusty and silty are ahead of all fractions in terms of potentially high thermodynamic parameters. At a depth of 56-75 cm, the tendency of the predominance of coarse-dusty and silty fractions persists.

Conclusion. The highest indicators of thermodynamic potentials in the horizon of 25-55 cm - ∆H kJ/mol—1415,6, - ∆G kJ/mol—1328,22, ∆S J /mol grad - 66.85. This horizon is characterized by the maximum values of the potential relative residual energy. The lowest potential is deeper than 75 cm. Entropy decreases with depth, in the horizon of 25-55 cm it is maximum.