The field work was carried out at the Experimental Station of the Desert Research Center, Balosa region, North Sinai Governorate, during two summer seasons of 2015 and 2016. To study the effect of subsurface drip irrigation (SDI) at depths of 10, 20 and 30 cm below soil surface and polymers at the rates of 0, 50, 100 and 150 kg polyacrylamide (PAM) per feddan (0.42 hectar) on productivity of maize under sandy soil conditions.
Results indicated that all studied parameters [plant height (cm), number of ears/plant, ear length (cm), ear diameter (cm), grains weight/ear, 1000-grain weight (g), harvest index (%), shelling (%), water use efficiency grain yield (kg/feddan), total biomass (kg/feddan), as well as, protein and oil (%) in grains] were significantly affected by subsurface drip irrigation in both seasons. The highest values of these parameters were recorded when subsurface irrigation was used at a depth of 30 cm below the soil surface, followed by 20 cm, while the minimum values were recorded for subsurface irrigation at a depth of 10 cm below the soil surface in 2015 and 2016 growing seasons. Increasing PAM rates from 0 to 150 kg/feddan caused a significant increase in all studied parameters of maize plants in the both seasons. The highest values of these parameters were obtained at 100 kg PAM/feddan compared with control treatment (without PAM). This has occurred in both
seasons and in all parameters, except plant height, ear diameter, water use efficiency, protein % and oil %, which were higher when using 150 kg PAM/feddan, but the differences between the two levels were insignificant in both seasons. Available data revealed that all studied parameters of maize were affected significantly by
the interaction between subsurface drip irrigation and polymers in both seasons, except no. of ears/ plant, ear diameter and ear length, which did not reach a significant level in the two seasons. Maximum values of the interaction between subsurface drip irrigation and polymers were obtained when subsurface irrigation was used at a depth of 30 cm below the soil surface with the rate of polyacrylamide (100 kg/feddan) in two seasons under sandy soil conditions.