Temperature‐humidity‐density dependent evaporation behaviour of clay and sandy clay

Abstract To compare the disparities between free water evaporation and soil water evaporation, and unveil the temporal impact of soil water evaporation in diverse environments, a series of experiments were conducted to observe the soil water content in different temperature and humidity environments. Meanwhile, the soil water characteristic curve (SWCC) and the evaporation process of free water in air were determined, and the sensitivities of temperature, humidity and density on the soil water evaporation process were analysed. The results demonstrated that both external temperature and humidity can serve as variables for controlling the evaporation rate of soil water. These factors exerted a dynamic influence on the evaporation process, with the impact of each factor tending to stabilize as soil water content decreased. The evaporation rate of soil water was higher than that of free water at the initial stage and was lower than that of free water after the soil reached the residual water content; soil water tended to exist in a state with higher entropy than that of free water. This study provides valuable insights for the establishment of a soil water evaporation model.