Soil Salinity Control Using Dry Drainage Concept
The conventional drainage methods such as lateral drainage, vertical drainage and interceptor drains have been used for many years to control soil salinity and water table. These methods increase agricultural productions but their installations are expensive and cause environmental pollutions. Therefore, in recent years, less expensive and more environmental acceptable drainage methods such as dry drainage have been introduced. In this method, the natural soil system is used to reclamate soil and evaporation of non-irrigated soil (fallow soil) is used to control salinity and water table of irrigated soil. There are few researches about the design and performance of this method of drainage under different soil and water conditions. Therefore, the objective of this study was to evaluate the performance of dry drainage under different soil and irrigation water salinities. A physical based model was constructed and used to simulate dry drainage and collect data. The model was studied for different combinations of soil salinity, irrigation water salinity and water table position. During each experiment and for each of the above conditions, irrigation water, evaporation and soil salinity were measured and compared. The results showed that dry drainage can reduce soil salinity significantly. As the salinity of fallow soil increased, the daily evaporation and performance of dry drainage decreased. For dry and semi dry regions, which have suitable conditions for dry drainage, to control and reduce soil salinity, the use of dry drainage is recommended.
Keywords- Dry Drainage, Salinity Control, Shallow Water Table, Evaporation, Fallow Land.