Effect of Irrigation with Wastewater on Some Physiological and Morphological Characteristics of Rosmarinus Officinalis (Case Study: Yazd City Wastewater)

Due to the limited resources of the water and the excessive growth of the population, the use of sewage in agriculture and green space irrigation is inevitable. In this regard, a research was carried out in city of Yazd to investigate the effect of irrigation with refined and untreated sewage on Rosmarinus officinalis, a species in the urban green space. This study was carried out in a randomized complete block design with five treatments (drinking water, refined wastewater, non-refined wastewater, refined wastewater + drinking water with a ratio of 1:1 and non-refined wastewater + drinking water with a ratio of 1:1) and 5 replicates. The results of chemical characterization of irrigation treatments showed that pH (7.2) and EC (1.27 ds/m) and the concentration of heavy metals, Pb and Zn in the effluent were in accordance with the FAO standard (0.5 and 0.24 mg/l, respectively) but cadmium concentration in both treatments was higher than the FAO standard level (0.02 and 0.04 mg/l). The results of morphological traits of Rosmarinus officinalis showed that there was no significant difference between different concentrations of sewage in terms of plant growth and root dry weight (p >0.05). The effect of irrigation with wastewater on dry weight of shoot and plant diameter was statistically significant (p <0.05). The highest dry weight and diameter were obtained with non-refined wastewater. The results of physiological traits such as chlorophyll a, chlorophyll b, total chlorophyll, glucose and proline showed a significant difference between treatments (p <0.05). The highest amounts of chlorophyll a, chlorophyll b, and total chlorophyll were observed for the irrigation with refined wastewater, and the highest amount of glucose and proline was related to irrigation with non-refined wastewater.