Deficit Irrigation Effects on Rosemary Plant (Rosmarinus officinalis L.) Parameters in a Semi-arid Climate

Deficit Irrigation is one of the ways to use water resources efficiently. In this method, a part of the plant's water requirement is eliminated so that it does not have significant effects on its yield. In this study, between ۲۰۱۷ and ۲۰۱۸, the effects of deficit irrigation on rosemary plant was investigated. The research site was the research station of the Water Engineering Department of the Campus of Agriculture and Natural Resources of Razi University in Kermanshah, by using the available Lysimeter Two-factor factorial based on a completely randomized design with four treatments (۱۰۰, ۷۵, ۵۰ and ۲۵% of water requirement) and three replications were applied. The results showed that irrigation treatments of ۷۵% and ۵۰% of plant water requirement had the same performance in producing essential oil at the rate of ۰.۳ cm۳/plant. However, the highest amount of essential oil production with a value of ۰.۴ cm۳/plant was observed in full irrigation treatment. From the obtained results, it can be concluded that increasing the level of deficit irrigation significantly affected the Rosemary components such as root depth, essential oil, dry matter, and reduced all indicators (except the number of branches) compared to the control treatment. Finally, due to the reduction of all plant parameters, the amount of essential oil and dry matter yield due to increasing the level of water deficit, irrigation of rosemary with a deficit irrigation level of ۵۰% does not seem reasonable and cannot be recommended. But at the ۷۵% level, this reduction in performance can be considered acceptable and based on results in the case of rosemary cultivation to produce dry matter, irrigation at the rate of ۷۵% of the plant requirement is sufficient, but in the case of rosemary cultivation to produce essential oil, the plant's water requirement should be fully met.

Keywords:

Lysimeter , Irrigation , Oil , Kermanshah