Enhancing phytoremediation efficiency using regulated deficit irrigation

In this study, Beta vulgaris L. var. cicla was grown in cadmium-contaminated soil in a greenhouse. Regulated deficit irrigation was applied using three different irrigation levels (T1: 300 L, T2: 200 L, T3: 100 L per block during each irrigation event during the organogenesis stage; T1 was the control) to examine the effects on phytoremediation efficiency. According to the experimental results, the regulated deficit irrigation treatment (T2) decreased the Beta vulgaris L. var. cicla shoot biomass by 15.8%, increased the Cd concentration in the shoots by 23%, and maintained a constant root-shoot ratio. By contrast, T3 decreased the Beta vulgaris L. var. cicla shoot biomass by 33.0%, decreased the Cd concentration in shoots by 9.8%, and increased the root-shoot ratio by 62.8%. The Cd remediation potential efficiency (PE) of treatment T2 was 5.42 g ha-1 – i.e., 39.7% higher than that of T1 and 61.8% higher than that of T3. This study indicated that regulated deficit irrigation can be used to enhance Cd phytoremediation and save water, but should be applied in a suitable way.