Effect of Saline Water Management on Soil and Tomato Yield in Subsurface Drip Irrigation

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 ECe measurement in various depths down to 90 cm revealed that the highest ECe (3.36 dS/m) occurred in different depths in M2S4 treatment.