Evaluation of physical and economic water productivity under regulated deficit irrigation and partial rootzone drying of sunflower crop

Managing water consumption and increasing water productivity by applying low irrigation methods in the agricultural sector is one of the most important measures to adapt to water scarcity. In this study, the effect of controlled and incomplete root irrigation on the physical and economic water productivity of sunflower plants was investigated in the form of randomized complete blocks. The treatments included full irrigation(FI), adjusted low irrigation(DI) and incomplete root irrigation (PRD) at two levels of 75 and 55%. The results showed that the application of PRD75 and DI75 treatments reduced water consumption by 16.52% and the application of PRD55 and DI55 treatments caused a reduction of 29.51% in the plant growth period, compared to the FI treatment. On the other hand, the effect of treatments on the physical efficiency of irrigation water on grain yield was significant at the level of 1%. The highest amount of physical productivity of irrigation water on grain yield was related to PRD75 treatment with a value of 1.275 kg/m3. The effect of the treatments on the physical efficiency of irrigation water on plant survival was also significant at the probability level of 1%. The highest amount of physical efficiency of irrigation water on plant biomass yield was related to FI treatment with a value of 4.29 kg/m3. Also, the effect of treatments on the economic efficiency of irrigation water on grain yield was also significant at the probability level of 1%. The highest amount of economic efficiency of irrigation water on grain yield was related to PRD75 treatment with the amount of 414.6 thousand rials per cubic meter. Therefore, it was recommended to use the incomplete root irrigation method at the level of 75%, due to the high physical and economic efficiency of irrigation water on seed yield, as well as saving water consumption.