In this study, raw and treated wastewaters were reused for potato cultivation in order to verify the effect of wastewater on crop yield, crop's heavy metals' concentration as well as some major traits of potato. To this regard, a completely randomized test was designed with five water treatments and three replications. The watering were as follows: raw wastewater (T 1 ), treated wastewater (T 2 ), a combination of 50 % raw wastewater and 50 % fresh water (T 3 ), a combination of 50 % treated wastewater and 50 % fresh water (T 4 ), and fresh water (T 5 ). The experiments were run during October 2009-June 2010 in the greenhouse of Bu-Ali Sina University. The results show that the effects of treatments were significant on the length and number of stems per plant (p \ 0.05). The number of nodes and weight of tubers, crop yield and heavy metal (cadmium, nickel and lead) concentration in shoots and tubers were also significant (p \ 0.01). The results indicated that the highest length of stem (55.44 cm) was obtained in T 2 which had no significant differences from that of T 1 . The maximum and minimum tuber weights and crop yield were obtained in T 1 and T 5 , respectively. Based on crop yield rate, the watering ranked as follows: T 5 . The maximum and minimum heavy metal values were observed in T 1 and T 5 , respectively. Based on the cadmium, nickel and lead accumulations in shoots and tubers (except cadmium in shoots), the watering treatments ranked as:

This study is an experiment designed with five watering regimes as follows: raw wastewater (T1), treated wastewater (T2), a combination of 50% raw wastewater and 50% fresh water (T3), a combination of 50% treated wastewater and 50% fresh water (T4), and fresh water (T5). The results show that the average Mn, Fe, Cu and Zn values in the drained water were less than the input water. The effect of watering on heavy metal concentration of the drainage water was statistically significant. Temporal analysis showed increasing trends for the heavy metals from T1 to T5. In the case of T1, after the third irrigation programme, Zn, Mn and Fe concentrations were reduced. Based on Pearson's correlation coefficients, Mn, Fe, Cu and Zn in drainage waters had significant positive correlation with each other. Also, the treatments had significant effects on heavy metal concentrations in potato shoots and tubers (except Zn in tubers). Based on heavy metal accumulation in drainage waters, potato shoots and tubers, the treated watering order was T1 > T3 > T2 > T4 > T5 (except Fe in shoots). The heavy metal concentration in tubers was less than in shoots. Cu and Zn accumulation in potato was within standard limits. Copyright © 2014 John Wiley & Sons, Ltd.