Effect of irrigation management with saline water on some agronomic and physiological traits of maize hybrid 704

In order to evaluate the effect of three irrigation methods including surface irrigation (I1), daily sprinkler irrigation (I2), post-irrigation sprinkling with fresh water (I3), and different levels of salinity including 2.9 (control), 3.5, 4.1, 4.7 and 5.3 dS.m-1 on agronomic and physiological traits of maize, a field experiment as factorial was carried out based on randomized complete block design with three replications during 2013-2014 in College of Irrigation science, Shahid Chamran University of Ahvaz. To apply salinity, a sprinkler irrigation system was used to establish minimum and maximum salinity levels on two parallel pipelines on both sides of field. Overlapping sprinklers led to establish a linear salinity gradient. Irrigation methods I3 and I2 with 4750 and 4160 kg h-1 had higher and lower amounts of grain yield, respectively. Water salinity significantly decreased stomatal conductance, chlorophyll index, leaf area index, K concentration and ratio of potassium to sodium, and higher reductions in these traits was observed in sprinkler irrigation. Daily sprinkler irrigation and surface irrigation showed the higher and lower Na concentration, 18.2 and 15.1 mg kg-1, respectively. These findings showed that, the threshold value of salinity for most traits and all irrigation methods was found to be ~4.1 dS.m-1. With the given water resources limataion and saline water resources in Iran, post-irrigation sprinkling with fresh water might be used for irrigating row crops such as maize with a lower yeild loss.