This lesson demonstrates the applicability of PLAXIS to agricultural problems. The potato field lesson involves a loam layer on top of a sandy base. Regional conditions prescribe a water level at the position of the material interface. The water level in the ditches remains unchanged. The precipitation and evaporation may vary on a daily basis due to weather conditions. The calculation aims to predict the variation of the water content in the loam layer in time as a result of time-dependent boundary conditions.