The effect of surface and subsurface drip irrigation in the presence of shallow saline water table on the two-dimensional distribution of soil moisture and salinity, morphological characteristics and maize yield

In the south of Iran, due to being located in the arid and semi-arid regions, the agricultural sector faces soil salinity resulting from the capillary rise of salt from the shallow saline water table to the soil surface and reducing crop yield. The objective of this research was to investigate the effect of surface drip irrigation (DI) and subsurface irrigation (SDI) methods on soil profile moisture and salinity distribution, maize (SC 703) yield, and irrigation water use efficiency in the presence of shallow saline water table (60 and 100 cm), during summer and spring seasons of 2021. A factorial experiment was conducted based on randomized complete block design with three replications in drained lysimeters filled with loamy soil (specific gravity 1.45 g cm-3) in field conditions. The results showed that the accumulation of salt above the dripper in subsurface irrigation method at both SDI100 and SDI60 treatments, was significantly more than the surface irrigation method (p<0.01). The results also revealed that summer maize yield was more than spring maize yield. Furthermore, in the summer season, irrigation in the root development zone in the SDI100 and SDI60 treatments caused an increase in the maize yield by 25 and 61%, respectively, and Water Productivity Index (WP) by 25 and 58%, respectively, in comparison to DI100 and DI60. Evaporation in SDI60 and SDI100 treatments was 26-30% and 43-51% lower than DI60 and DI100 treatments, respectively. The results of this research showed that SDI is more effective than DI in controlling soil profile salinity and plant yield.