48. Water Use Efficiency for Leaching Saline-Sodic Clayey Soils: Case Study of Tina Plain Area of Egypt

In Egypt, saline-sodic clayey soils represent approximately 109,200 ha of the delta. At present these areas are either of poor or low quality mainly due to salinity and sodicity problems. In Tina Plain area of North Sinai, there are about 6,300 ha of problematic saline-sodic clayey soils. Tina Plain area of North Sinai is one of the three regions of the reclamation areas under El-Salam canal development project. It represents the first region of the project. This project envisages the reclamation of an area of 170,000 ha. Therefore, it is important to measure the water use efficiency for leaching saline-sodic clayey soils in this area using irrigation water from El-Salam canal to evaluate the agro-economic value of this project. The study was conducted in an experimental field of saline-sodic clayey soils in Tina Plain area. The experimental field has an actual area of 25 ha. The soil is saline with heavy clay texture, poor drainage, shallow groundwater tables and 30-cm surface salt layer. From the site characteristics it is realistic that the most appropriate strategy for this stage of reclamation is to apply intermittent leaching and surface drainage. This strategy succeeded to remove the salt layer within 6 months of leaching. The study was extended for 1 year. The results indicated that 2.9 t of salts were leached for each hectare per day with irrigation water quantity of 223 m³. The average soil salinity before leaching was 400 dS m⁻¹ (0–50 cm) and 300 dS m⁻¹ (50–150 cm). Leaching decreased the soil salinity at the surface layer to about 100 dS m⁻¹ with leaching efficiency of 75%. For the other layer, EC decreased to 150 dS m⁻¹ with leaching efficiency of 50%. The water table depth below ground surface was lowered from 0.16 m to about 0.86 m below ground surface. This indicates that the soil properties also improved due to the salt leaching process.