Beschreibung:
<jats:sec><jats:label /><jats:p><jats:list list-type="bullet">
<jats:title>Core Ideas</jats:title>
<jats:list-item><jats:p>Least‐action and variational principles were used to analyze soil water content distribution.</jats:p></jats:list-item>
<jats:list-item><jats:p>An analytical solution of a one‐dimensional horizontal‐absorption equation was proposed.</jats:p></jats:list-item>
<jats:list-item><jats:p>A new method to predict the distribution of SWC and estimate the Brooks–Corey model parameters.</jats:p></jats:list-item>
</jats:list></jats:p><jats:p>A simple and approximate analytical solution of a one‐dimensional horizontal‐absorption equation is of great importance for measuring soil hydraulic properties. Several methods for determining the parameters of the Brooks–Corey (BC) model are promising, but all are based on assumptions to some degree. We have developed a new analytical solution for one‐dimensional horizontal constant‐saturation absorption based on the least‐action and variational principles. The profiles of soil–water content (SWC) calculated by the new method were very agreeable with numerical solutions, especially for high water contents. A comparison with a numerical solution calculated by HYDRUS‐1D indicated that the analytical solution accurately estimated the BC model parameters for calculating the profile of SWC, cumulative infiltration, infiltration rate, and wetting‐front distance (WFD). We also compare the merits and demerits between the new analytical method and other approximate methods. The proposed analytical method provides a new and approximate method to predict the distribution of SWC and estimate the BC model parameters.</jats:p></jats:sec>