Effects of deficit irrigation on vegetative growth, yield and water use efficiency of sweet orange (Citrus sinensis var. Mars Early) in south of Kerman

Since the regulated deficit irrigation and subsurface irrigation cause to increase high water use efficiency and water saving, a field factorial experiment was carried out based on randomized complete block design with three replications at the South Kerman Agricultural and Natural Resources Research and Education Center during 2014-2016. In this study, two factors including deficit irrigation (100 percent ETc in total growing stages, 60-100 percent and 80 percent ETc except in the flowering and fruit-filling stages) and irrigation method (deep subsurface, subsurface drip and surface drip irrigation) were evaluated. Vegetative traits, yield and water use efficiency were measured during growing period of sweet orange (Citrus sinensis var. Mars Early) grafted on Citrus aurantium. The results showed that the regulated deficit irrigation practices save water compared to complete irrigation of about 17 percent and reduce vegetative growth, although there were no statistically significant differences in yield. Subsurface irrigation saved water compared to surface drip irrigation of about 10 percent, improved vegetative growth and water use efficiency. Therefore, it can be concluded that regulated deficit irrigation and subsurface irrigation are very effective for improving the water use efficiency and water saving.