Document Type : Research Paper

Abstract

In this research, effects of subsurface drip irrigation method on soil and tomato yield was investigated under different salinities and two irrigation management strategies: M₁= alternating irrigation with fresh water and saline water, and M₂₌ saline water in the first half of each irrigation event and fresh water in the second half. The experiment was conducted in 320 m² area including 30 plots.  Drippers were placed at 15 cm depth and, in order to consider the interaction of salinity levels and management strategies, split plot design with three replications was used in which management strategies (m₁ and m₂) were in the main plots and subplots contained different levels of salinity including 0.68, 2, 4, 6, and 8 dS/m (S₀, S₁, S₂, S₃, and S₄, respectively).  Results showed that yield of tomato decreased with increasing irrigation water salinity levels and the highest and lowest yields were in the M₂S₀ (52.44 ton/ha) and M₁S₄ (23.363 ton/ha) treatments, respectively. Also, average yield in M­₁ strategy was 17.77 % less than M₂ strategy. Applied irrigation water decreased with increasing salinity levels and, therefore, water use efficiency (WUE) increased. The highest WUE was in the M₁S₄ (7.78 kg/m³) and M₂S₄ (7.77 kg/m³). The EC_e measurement in various depths down to 90 cm revealed that the highest EC_e (3.36 dS/m) occurred in different depths in M₂S₄ treatment.