The effects of wastewater irrigation on vegetative performance of various woody species under arid condition (Case study: Yazd city)

This experiment was conducted to evaluate the establishment and adaptability of woody species under wastewater irrigation condition in arid climate. This experiment carried out in Yazd city wastewater treatment station with 11 tree species under randomized complete block design with three replications. The species included Eucalyptus camaldulensis E. microtheca, Elaeagnus angustifolia, Tamarix aphylla, Melia azedarach, Pinus eldarica, Populus euphratica, P. alba × P. euphratica, Morus alba, Cupresus simperverence and Ailanthus altissima. In each plot, trees were planted with 48 seedlings for each species. Immediately after planting, the seedlings were irrigated with wastewater for 15 days, followed by further irrigations in 20-30 days intervals after the establishment. After 4 years, the effects of wastewater on establishment and growth, including survival percentage, height growth, the average diameter of the crown, crown volume, collar diameter and diameter at breast height (DBH) were measured. The results showed that the P. eldarica had highest rates of deployment with 100% of establishment. However, no significant differences were observed with other species including M. azedarach, E. camaldulensis and, E. microtheca. For all growth indicators and yield traits, the T. aphylla tree showed better performance, although it did not significantly differ with many others species. The results of this study showed that woody species such as E. camaldulensis, E. microtheca, M. azedarach, E. angustifolia, P. euphratica and P. eldarica can be irrigated with wastewater under arid condition due to their better establishment, growth and slenderness coefficient compared to other species.