Richards Equation

This article talks about Richards Equation, which introduced in 1931 is the main tool for ” Simulations of water transport in soil are ubiquitous”. For experiments on water transport in soil horizontal columns, Richards’ equation predicts that volumetric water contents should depend solely on the ratio. The corresponding mathematical model is a generalized Richards equation in which the derivative of water content on time is a fractional one with the order equal or less than one. It is a nonlinear partial differential equation, which is often difficult to approximate since it does not have a closed-form analytical solution.