Effect of controlled irrigation on accumulation of heavy metal Cd, Cr in soil-plant system in rice paddy

In order to reveal the impact of irrigation management on heavy metals Cd, Cr inputs and distribution and enrichment of Cd，Cr in rice plants，field experiments were carried out to determine contents of heavy metal Cd, Cr in soil-plant system in rice paddy. The results showed that controlled irrigation mode can reduce seasonal irrigation inputs of heavy metals Cd, Cr by 60.8% and 59.8% respectively, compared with traditional irrigation. Controlled irrigation leaded to significant change in accumulation of Cd, Cr in the aboveground part, and increased accumulation of Cd and Cr by 29.5% and 5.4% respectively, compared with traditional irrigation. Cd and Cr were mostly stored in the root of rice, with only a small part of them migrating to the aboveground. Enrichment coefficients of Cd and Cr in roots of rice with controlled irrigation paddy were higher than those with the traditional irrigation. Controlled irrigation enhanced Cd and Cr migration ability to the rice plants, and migration of Cd and Cr to the aboveground. Therefore, controlled irrigation can decrease input risk and soil cumulative risk of Cd and Cr in rice paddy, but it also can increase rice absorption of Cd. Further study on soil heavy metals pollution remediation should be carried out.