Effect of irrigation with the different ratios of drainage water with fresh water and foliar fertilizer application on yield and yield components of Roselle (Hibiscus sabdariffa L.)

Abstract
Background and objectives: Roselle belongs to the malvaceae family, is an annual or biennial plant cultivated for its stem, fiber, edible calyces, leaves and seeds. The crop is used in a variety of ways for home consumption, medicinal and industrial uses. Also used for its antibacterial, antifungal, hypocholesterolemic, antispasmodic and antihypertensive actions. Increasing demand for water resources, particularly in arid and semi-arid in the world, has led farmers use the poor quality water, such as drainage water and saline groundwater. The present investigation aims to study the in an appropriate manner, the use of saline drainage water and complete fertilizer to achieve the highest calyx yield.

Materials and methods: This experiment was conducted to evaluate the yield and yield components of roselle in 2014 at the Agricultural research Institute of Zabol University in a complete randomized block in split-plot design with three replications. Treatments included three levels of irrigation namely, irrigation with fresh water at all stages of grows (control), irrigation with drainage water and fresh water alternately and irrigation with drainage water for all growing stages, as main plot and spraying with three levels of complete fertilizer (NATBA-LIB): non-spraying (control), spraying with 600 gr and spraying with 1200 gr of complete fertilizer per hectare, as subplots. Characteristics plant height, stem diameter, number of fruiting branches, thousand– seed weight, capsules weight, plant fresh and dry weight, number of fruit in plant, calyx yield and flower protein percentage were evaluated.

Results: The results showed that the irrigation treatment was significant effect at 1% probability level in all variables except plant height, stem diameter, thousand–seed weight. Also the highest plant height, stem diameter, number of fruiting branches, thousand seed weight, capsules weight, plant fresh and dry weight, number of fruit in plant, calyx yield were obtained from 1200 gr.ha-1 of complete fertilizer spraying. There were significant affect by interaction irrigation and spraying in other variables except plant height, stem diameter and thousand seed weight. The highest (227.6 kg.ha-1) and the lowest (69 kg.ha-1) calyx yield was produced under the traits irrigation with fresh water at all stages of grows (control) and irrigation with drainage water for all growing stages respectively. The highest of fruit number in plant (59) was obtained from 1200 gr.ha-1 of complete fertilizer application, although not significant differences between control and 600 gr.ha-1 treatments. In drainage and fresh water alternately treatment the weight of the capsule showed 20% increase compared with drainage water application. The highest flower protein percentage (22.5%) was obtained from 600 gr.ha-1 of complete fertilizer application and irrigation with drainage and fresh water alternately treatments.

Conclusion: The results showed that the highest of calyx yield on this plant was related from irrigation with fresh water treatment. Therefore, in order to achieve the desired quantitative and qualitative characteristics in roselle, using the treated irrigation with fresh water at all stages of grows and complete fertilizer has recommended. The best method was used irrigation with drainage water and fresh water alternately method dual with complete fertilizers If hadn't enough fresh water for all stage grows or may not be any more economically feasible and recommendable due to the increasing cost and limitation of renewable water resources.