海泡石配施石灰对水稻镉和中微量元素有效性的影响

    Effects of Sepiolite Combined with Lime on the Availability of Cadmium and Trace Elements in Rice (Oryza sativa)

    • 摘要: 采用田间小区试验, 试验设置对照(CK)、低量海泡石处理(S1)、高量海泡石处理(S2)、石灰处理(L)、低量海泡石和石灰处理(S1L)、高量海泡石和石灰处理(S2L)6个处理, 探究海泡石和石灰单施及两者配施对土壤Cd和中微量元素(Fe、Mn、Zn和Cu)有效性以及水稻籽粒Cd和中微量元素含量的影响, 为酸性Cd污染稻田的稻米安全生产和中微量元素营养管理提供参考。结果表明, 海泡石和石灰单施及两者配施均可显著提高土壤pH值、交换性Ca和有效态Si含量, 显著降低土壤有效态Cd、Fe、Mn、Zn和Cu含量; S2L处理土壤CaCl2提取态Cd含量显著降低98.0%。海泡石和石灰单施及两者配施均显著降低稻米Cd、Mn和Cu含量; S2L处理稻米Cd含量降低62.0%, Cd从水稻根部向稻米的转运系数(TF米/根)显著降低48.7%。海泡石和石灰通过提高土壤pH值、交换性Ca和Mg以及有效态Si含量而降低土壤Cd有效性, 土壤Cd有效性和TF米/根 降低是稻米Cd含量降低的主要原因。海泡石和石灰配施对土壤Cd有效性和稻米Cd含量的降低效果优于两者单施, 高量海泡石和石灰配施处理土壤Cd有效性和稻米Cd含量降幅最大。海泡石和石灰单施及两者配施处理土壤有效Fe、Zn和Cu含量处于"丰富"水平, 土壤有效Mn含量水平降低1~2个等级, 稻米Mn和Cu含量处于正常营养范围内。海泡石和石灰配施可降低Cd的植物有效性和土壤有效态Mn水平, 需结合其他措施提高土壤有效态Mn水平。

       

      Abstract: A field plot experiment was conducted to investigate the effects of single and combined application of sepiolite and lime on the availability of Cd and trace elements (Fe, Mn, Zn and Cu) in soil and their concentrations in rice grains. Six treatments were set up, i.e., control (CK), low dosage of sepiolite (S1), high dosage of sepiolite (S2), lime (L), low dosage of sepiolite and lime (S1L), and high dosage of sepiolite and lime (S2L). The aim of this study is to provide a reference for rice safe production and nutrition management in acid Cd-contaminated paddy fields. The results show that single application of sepiolite and lime and their combined application significantly increased the pH value, concentration of exchangeable Ca and available Si, but significantly decreased the concentration of available Cd, Fe, Mn, Zn and Cu in the paddy soil. The concentration of CaCl2-extracted Cd in the soil treated with S2L was significantly reduced by 98.0%. The alone and their combined applications of sepiolite and lime significantly reduced the concentration of Cd, Mn and Cu in rice grains. The S2L decreased the Cd concentration in rice grains and the transfer coefficient (TF rice / root) from root to grain by 62.0% and 48.7%, respectively. Sepiolite and lime reduced soil Cd availability by increasing soil pH and concentration of exchangeable Ca, Mg and available Si. Soil Cd availability and TF rice / root reduction were the main reasons for the decrease of Cd concentration in the rice grains. The combined application of sepiolite and lime is superior to their single application in reducing soil Cd availability and grain Cd concentration. The high amount of sepiolite and lime has the best performance for decrease in soil Cd availability and grain Cd. The available Fe, Zn and Cu enriched in the soil of single and combined application of sepiolite and lime. The available Mn in the soil decreased by 1-2 grades, but concentrations of Mn and Cu in the rice grains were within the normal nutrient range. The combined application of sepiolite and lime reduced the availability of Cd and the level of available Mn, and thus other measures should be combined to increase the level of available Mn.

       

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