Temperature Factor of Soil Water-Holding Capacity

— The effect of temperature in the range from 4 to 50°C on the water retention curves in five soil samples of different textures was studied. The method of thermostatic centrifugation on the basis of a laboratory centrifuge Sigma 2-KHL (Germany) was used, which made it possible for the first time to evaluate the influence of the temperature factor in a wide range of the thermodynamic potential of water from 0 to 3000 J/kg. Using statistical methods, two physically-based hypotheses of the relationship between temperature and thermodynamic potential—“capillary” (a decrease in water retention with increasing temperature) and “surface forces” (temperature invariance of water retention)—were evaluated. A representative analysis of 4–8 repetitions of each experiment did not reveal a statistically significant effect of the temperature factor on the water retention curves in all the studied samples. A fundamental explanation of the obtained results is proposed on the basis of Polanyi’s potential theory and the ion-electrostatic mechanism of disjoining water pressure according to Deryagin.