Drainage by evaporation for soil salinity control

The paper discusses the concept of drainage-by-evaporation ('dry drainage') from fallow areas as a possible method for soil salinity control. The method requires retirement to be imposed on a part of the irrigated land. The remainder of the land is used for crop production. While the retired area is unirrigated, normal irrigation practices are carried out on the remaining area. For the method to be effective, it is essential that a shallow water table and high evaporation rates are present. These conditions are the characteristics of arid and semi-arid regions. Field-scale numerical indicated that it is possible to obtain an optimal land use pattern for drainage-by-evaporation scheme. Factors influencing the design are related to the climatic conditions, the practiced crop, the soil properties and economic factors.