Maize is a moderately salt-sensitive crop, but there is little information about its morpho-physiological and grain yield responses to sprinkling irrigation with saline waters. To evaluate the effect of irrigation with
saline water with different levels of electrical conductivity of 2.9 (control), 3.5, 4.1, 4.7 and 5.3 dS.m^-1 on grain yield and morpho-physiological traits of maize hybrid KSC704, a field experiment was carried out using randomized complete block design with three replications in Shahid Chamran University, Ahvaz, Iran, in summer of 2013. To apply salinity levels, a sprinkler irrigation system was used to establish minimum and maximum salinity levels on two parallel pipelines on both sides of the field. Overlapping sprinklers led to establish a linear salinity gradient. Result showed that increasing the electrical conductivity of water and soil salinization, especially at 4.7 and 5.3 dS.m^-1 significantly decreased grain yield (17.75 and 25%, respectively), relative water content (13 and 17%, respectively), stomatal conductance (41 and 61%, respectively), chlorophyll index (10 and 10%, respectively), leaf area index (26 and 37%, respectively) and ratio of potassium to sodium (45 and 39%, respectively), and increased leaf sodium content (20 and 28%, respectively) when compared with the control. In sprinkler irrigation method, it seems that due to both root and foliar absorption of salt, via impairment in the physiological functions of the plant, it caused reduction in dry matter and grain yield. In conclusion, these findings showed that, in sprinkler irrigation the threshold of salinity was ~4.1 dS.m^-1. With regard to the saline water resources in Iran, especially in warm areas of Khuzestan, sprinkler irrigation may be beneficial in row crops, such as maize, production.