Effect of PRD Deficit-irrigation Method and Growth Stabilizer on Yield, Yield Components and Water Use Efficiency of Safflower

While Iran is confronted with deficiency of fresh water resources, raising agricultural water use efficiency (WUE) is inevitable. A management method which could be effective in increasing agricultural WUE is PRD irrigation method. In PRD method, half of the root zone is irrigated and the other half is kept dry intermittently. The objective of this research was to study yield, yield components and WUE of safflower, using PRD irrigation method and a growth stabilizer in two soil textures. The factorial experiment, based on complete random design and three replications, included three irrigation methods (T1, complete irrigation T2, PRD with barrier T3, PRD without barrier), two levels of stabilizer (B1, spraying sodium salicylate and B2, without spraying sodium salicylate) and two soil textures (S1, clay loam and S2, sandy loam). Results showed that the PRD method in T2 treatment decreased plant height by 54.1%, number of heads by 68%, 1000-seed weight by 32%, plant dry-weight by 345, seed yield by 30%, harvest index by 17.6% and water consumption by 50%, as compared with T1 treatment. But WUE was increased by 35%. WUE of T3 treatment was 18.5% less than T2 treatment. Seed yield in sandy loam soil (8.8 g per plant) was more than seed yield of clay loam soil (3.8 g per plant). Application of growth stabilizer in T1, T2 and T3 treatments increased WUE by 14.3, 7.1 and 8.7%, respectively, as compared to non-sprayed treatments. In general, the PRD irrigation method and spraying sodium salicylate on the plants enhanced WUE of safflower in sandy loam soil. Implementation of this irrigation method in the field needs further investigations