控制灌溉模式对稻田土壤-植物系统镉和铬累积的影响

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

为了揭示不同灌溉模式Cd、Cr灌溉输入量差异及对Cd、Cr在稻田土植系统总累积的影响,基于田间试验开展了不同灌溉模式稻田土-植系统Cd、Cr含量观测。结果表明,控制灌溉与淹水灌溉相比在水稻全生育期可分别减少Cd、Cr灌溉输入量60.8%和59.8%。灌溉模式的改变显著影响了重金属Cd、Cr在植株地上部分的累积。与淹水灌溉相比,控制灌溉植株地上部分Cd、Cr累积量分别增加了29.5%和5.4%。植株吸收的Cd、Cr大部分储存在根部,只有少量向地上部分迁移,控灌植株根部Cd、Cr吸收富集系数大于淹灌处理。控制灌溉增强了Cd、Cr向水稻植株的迁移能力,以及Cd、Cr向地上部分迁移。因此控制灌溉减少了稻田重金属Cd、Cr的输入风险和土壤累积风险,但会导致水稻植株吸收Cd的增加,需要有针对性地进一步开展相关修复和防治研究。

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.