Investigation of the Using Heavy Metals-Contaminated Water with Subirrigation in Canola Cultivation

One of the ways out of the water crisis is to use polluted and non-conventional water. In this regard, a study was conducted in 2017 and 2018 in the Agricultural and Natural Resources College, the University of Tehran in the form of a completely randomized factorial design with four treatments, three replications, and a total of 12 experimental plots in the lysimeter environment. Experimental treatments included surface irrigation with contaminated water by heavy metals (SRC), surface irrigation with conventional water or control treatment (SRF), subirrigation with contaminated water by heavy metals (SBC), and subirrigation with conventional water (SBF). The texture of the soil inside the lysimeters was sandy loam, its pH was 7.4, and the heavy metals used were copper, zinc, and lead. The results showed that the highest copper concentration in SBC treatment was observed at a depth of 75 cm, which was 43% less than the maximum amount in SRC treatment, and 25 cm depth, which was significant at the level of 5%. Also, there was a difference between the maximum amount of soil zinc on SRC and SBC treatment of more than 4.2 mg/kg, and in subirrigation, 32% less zinc was absorbed into the soil, which was significant at the level of 5%. The average amount of copper uptake by the plant in SRC treatment was 4.97 mg/kg, which was 80% and 70% increase in copper uptake, respectively, compared to control and SBC treatment, and this difference was significant at the level of 1%. In general, top-down motion (SRC) is higher than bottom-up motion (SBC), indicating the use of heavy metal contaminated water in subirrigation.