Assessment of inter-plant emitter distance and effects of irrigation water salinity on APRDI using Hydrus-2D

Abstract in Undetermined
Modern irrigation techniques are becoming increasingly important in water-scarce countries. In this study, a two-dimensional water and solute transport model, Hydrus-2D, was used to assess the impact of inter-plant emitter distance (IPED) and irrigation water salinity on soil moisture and salinity distribution as well as on water balance components under alternate partial root-zone surface drip irrigation (APRDI) of tomato growing in loamy sand soil. Three IPED (20, 30, and 40 cm) and three irrigation water salinity levels (0, 1, and 2 dS/m) were used to execute different simulation scenarios. Simulation results indicated that the fluctuations in water content within the root zone were more pronounced in case of 20 cm IPED. The root water uptake increased as the IPED decreased. Using brackish irrigation water in APRDI caused significant augmentation in soil salinity in the top soil layer especially at the location of plant. The impact of irrigation water salinity on root water uptake increased as the IPED increased. As irrigation water salinity increased the root water uptake decreased. At plant location, soil salinity reached its highest values at the top soil layer in case of 30 and 40 cm IPED with brackish irrigation water. However, high soil salinity values were observed between the 40 and 65 cm depths in case of 20 cm IPED. Based on the results, it appears that APRDI with non-saline irrigation water is more effective with short IPED considering that approximately half of the root system was exposed to drying cycle. In addition, short IPED is recommended in APRDI when using brackish irrigation water especially for plants with shallow root system taking into account crop salinity tolerance.