Evaluating the Effect of Different Methods of Deficit Irrigation on Yield, Yield Components and Irrigation Water Productivity of Forage Maize

An experiment was conducted in order to investigate the effect of deficit irrigation method on yield, yield components and water use efficiency of forage maize (KSC 704) an experiment was conducted during 2013 and 2014 growing seasons in mashhad. A factorial experiment based on randomized complete blocks design with four replications was carried out. Treatments included full irrigation treatment, deficit irrigations (regulated deficit irrigation and replacements of 80 and 60% of total water requirement, variable PRD at 100, 80 and 60% of water requirement and fixed PRD at 100, 80 and 60% of water requirement). Deficit irrigation resulted in water use saving at the rates of 14-28 %. Results showed that plant height, ear height and stem diameter decreased by deficit irrigation. The highest fresh forage yield (75095 kg/ha) was produced by full irrigation treatment. There was no significant difference between fresh forage yield of full irrigation treatment and plants which grew at 80% water replacement and variable PRD method (P≤0.01). The highest water use efficiency was 2.27 kg/m3 which belonged to variable PRD by 80% of water requirement.There was no difference between replacing 100 and 80% of water requirement by applying variable PRD. Overall, results showed that application of variable PRD method saved water by 14% compared with full irrigation treatment without significant reduction in yield and yield components of forage maize.