不同类型钙化合物对污染土壤水稻吸收累积Ｃｄ Ｐｂ的影响及机理

以潮泥田和红黄泥为供试土壤,利用盆栽试验研究了施用不同类型钙化合物(CaO、CaCO3、CaSO4)对水稻吸收累积Cd、Pb的影响及机理。结果表明,潮泥田施用CaO和CaCO3后,土壤pH值明显升高。当CaO施用量达到0.36gCa·kg-1时土壤有效态Cd含量显著降低,水稻糙米Cd含量也随之显著下降,降幅达26.3%;施用CaCO(30.24gCa·kg-1)和CaSO(40.24gCa·kg-1)后水稻糙米Cd含量降幅分别为23.7%(P0.05)和18.4%(P0.05)。红黄泥施用CaO、CaCO3和CaSO4后,土壤pH值变化趋势与潮泥田相同。当CaO施用量达到0.24gCa·kg-1时土壤有效态Cd含量显著降低,但水稻糙米Cd含量反而上升,当CaO施用量达到0.36gCa·kg-1时,与对照相比水稻糙米Cd含量增加34.5%(P0.05);当CaO施用量增至0.48gCa·kg-1时土壤有效态Pb含量明显增加,水稻糙米Pb含量也随之显著增加,增幅达41.7%。在等钙(0.24gCa·kg-1)条件下,潮泥田及红黄泥施用CaO、CaCO3和CaSO4后因pH变幅较小导致水稻糙米Cd、Pb含量无明显差异。综合分析认为,利用钙化合物控制污染土壤上水稻对Cd、Pb的吸收累积时,需要根据土壤Cd、Pb含量和pH综合考虑合理的钙化合物类型和用量。

Effects of Calcium Compounds on Uptake and Accumulation of Cd and Pb by Rice and Its Mechanism in Polluted Soils

Different types of calcium compounds(CaO,CaCO_3,CaSO_4) were applied in Alluvial Paddy Soil(APS) and Reddish Yellow Paddy Soil(RPS) polluted by cadmium(Cd) and lead(Pb) to study the uptake and accumulation of Cd and Pb by rice and its mechanism through a pot experiment. The results showed that pH value was increased significantly after CaO and CaCO_3 being applied in APS. Available Cd in soil was significantly lessened and Cd content in brown rice was decreased by 26.3％ when application of CaO reached 0.36 g Ca·kg~(-1). Cd content in brown rice was declined by 23.7％ (P<0.05) and 18.4％ (P<0.05) after CaCO_3(0.24 gCa·kg~(-1))and CaSO4(0.24 gCa·kg~(-1)) being applied in APS respectively. The change trend of soil pH value affected by application of CaO,CaCO_3 and CaSO_4 in RPS was the same as that in APS. Available Cd in soil was decreased remarkably when application of CaO reached 0.24 gCa·kg~(-1) But Cd content in brown rice was increased by 34.5％(P<0.05) as the application of CaO was amounted to 0.36 gCa·kg~(-1) Available Pb in soil was increased remarkably,and Pb in brown rice was increased by 41.7％ with the application of CaO up to 0.48 gCa·kg~(-1) There were no significant differences of Cd or Pb contents in brown rice among application of CaO,CaCO_3 and CaSO_4 with equivalent calcium (0.24 gCa·kg~(-1)) in those two soils. It was illustrated that there was slight effect of pH on uptake and accumulation of Cd and Pb by rice at 0.24 gCa·kg~(-1) application due to relative low pH change among the three equivalent calcium treatments. It could conclude that the types and amount of Ca compounds should be considered rationally to control the uptake and accumulation of Cd and Pb according to content of Cd,Pb and pH in polluted soil.