Management of Irrigation Water Salinity in Greenhouse Tomato Production under Calcareous Sandy Soil and Drip Irrigation

A greenhouse experiment was conducted during the growing seasons (2008/2009 and 2009/2010) to investigate the effects of water quality and soil amendments, irrigation methods and rates on tomato (Solanum lycopersicon L. cv. Red Gold) yield and water use efficiency (WUE). Irrigation management treatments were fresh (0.86 dS m-1) and saline waters (3.6 dS m-1), surface and subsurface irrigation methods, 2, 4, and 6 L h-1 irrigation rates applied at the same irrigation duration and interval, and clay deposit, organic matter, and control amendment treatments. The results showed that differences among treatments were highly significant (P< 0.05) for tomato yield and WUE. The interactions between water quality and the other three factors were highly significant (P< 0.05). Applying fresh water and clay deposit amendments in sandy soil under subsurface drip irrigation at 2 L h-1 flow rate irrigation, water saving occurred due to improving soil water distribution in root zone. On the other hand, fresh application of saline water and clay deposit or organic matter amendments in sandy soil under subsurface drip irrigation method at 6 L h-1 flow rate, reduced both high cost of water desalinization and deleterious effect of saline water. Therefore, this management practice is recommended for greenhouse tomato production.