Farmland pipe drainage is one of new engineering measures to improve saline-alkali soils.It is important to simulating farmland water and salt migration for the construction and management of a pipeline system on farmlands.In this study,the basic principle and parameters of the water management model DRAINMOD-S are comprehensively introduced on the bases of mathematically modeling flows and salt migration in saturated-unsaturated soils.The DRAINMOD-S model is used with the weather,soil and crop data collect...