Effects of magnetic irrigation water treatment on growth and yield characteristics of Hibiscus sabdariffa L. under water deficit stress

Water deficit is one of the most important challenges for the agriculture, especially in the arid and semi-arid regions of the world.Due to the high potential of some medicinal plants for cultivation under environmental stresses, cultivation of these plants in the low-yield fields can be considered. Therefore, to reduce the negative effects of water deficit on the growth of Hibiscus sabdariffa L., a factorial experiment was conducted in a completely randomized design with three replications in the research greenhouse of agriculture faculty, Birjand University in 2017. The experimental treatments included the amount of irrigation water at four levels (100, 80, 60, and 40% of the field capacity) and irrigation treatment with magnetic water at three levels (non-magnetic water (control), magnetized water with one, and two times passing through the magnetic field). The results showed that the effects of irrigation water amount treatments on the all measured traits and magnetic irrigation treatments on the all traits except leaf number were significant. Also, the interaction effects of irrigation water amount × magnetic irrigation treatments were significant on the plant height, number of bolls per plant, fresh and dry weight of aerial parts, dry weight of roots, and dry weight of sepals. Reducing the amount of irrigation water from 100 to 40% of field capacity caused a decrease in the spade number, stem diameter, number of leaves, and fresh root weight by 34.7%, 23%, 40.6%, and 27.6%, respectively. The mean comparison of interaction effects of irrigation water amount × magnetic irrigation treatments showed that irrigation with double-magnetized water improved all the traits compared to the irrigation with non-magnetic water. Therefore, it seems that the application of magnetic irrigation can be considered as one of the strategies to reduce the negative effects of water deficit.