This study offers a method of calculationof soil moisture evaporation from baresoils, which is based on the theory ofexchange processes in porous media. Thismethod has taken into account basiccharacteristics of porous media, as wellthe states of soils and the weatherconditions under which soil moistureevaporation occurred. Calibration of modelparameters has been carried out. The modelwas verified with natural measurement dataof different regions of the former SovietUnion.