Effects of irrigation with treated wastewater on yield and grain heavy metals content of barley (Hordeum vulgare L.) genotypes

To assess the effects of irrigation with treated wastewater on the grain yield, yield components and grain heavy metals content of barley genotypes, two-years field experiment was conducted on Research Field of Yazd Municipal Wastewater Purification Station in 2015-16 and 2016-17. Experimental design was split plot arrangement in randomized complete block with three replications. Treatments consisted of three irrigation water quality; treated municipal wastewater (WW), alternatively fresh water/treated municipal wastewater (FW/WW) and fresh water (FW) during growing stages as main plot and three barley genotypes; Loot, MSB-87-12 and Afzal as subplots. Results showed that, the highest spike.m-2 obtained in MSB-87-12 in 2015-16 (345) and Loot in 2016-17 (325) that were irrigated with treated wastewater. Overall, the results showed that the highest grain number.spike-1 and grain yield obtained for cv. Loot which was irrigated with treated wastewater in both years. Interactions between methods of irrigation and genotype did not significantly affect on heavy metals concentration (Fe, Cu, Mn, Zn, As, Cd and Pb) in barley grains. Treated municipal wastewater application caused an increase of trace elements (Fe, Mn, Zn, Cu, Cd, Pb and As) in grain of barley genotypes. However, the values obtained for all heavy metals were below the permissible limits recommended by the World Health Organization (WHO), European :union: (EU) and the Institute of Standards and Industrial Research of Iran (ISIRI). According to these results, the use of treated wastewater for irrigation of barley crop can suggested for higher grain yield, decreasing fertilizer application and protection of environment.