改良剂对Cd污染土壤中小白菜品质的影响

通过小白菜盆栽试验,以啤酒污泥、草木灰及其混合物作为土壤改良剂,以生物量、可溶性糖、维生素C和叶绿素含量为指标,研究了改良剂对小白菜品质的影响,并分析了土壤中Cd赋存形态的变化。结果表明,不同改良剂在性质和改良机制上存在差异,因此改良效果各不相同,其中啤酒污泥和草木灰的混合物的改良效果最好,其次是啤酒污泥,最后是草木灰。虽然3种改良剂均能降低小白菜茎叶中Cd含量和土壤中有效态(水溶态和可交换态)Cd含量,提高小白菜品质,但小白菜茎叶中Cd含量仍超过《食品中污染物限量》(GB 2762—2005)规定的蔬菜中Cd限量值。

Effects of amendments on quality of pakchoi in Cd polluted soil

The effects of different soil amendments(beer sludge,plant ash and their mixture)on the quality of the pakchoi were investigated through pot experiments.The biomass,soluble sugar,vitamin C and the chlorophyll content of pakchoi after applying different soil amendments were detected and the Cd speciation in soil was analyzed.The results showed that the improvement effects and mechanisms varied with different amendments due to their different characters.Among these amendments,the mixture was the most efficient in suppressing Cd uptake by pakchoi,and the beer sludge was better than that of plant ash.Although all the three improver could reduce the Cd content in pakchoi stems and leaves,effective Cd content(water soluble and exchangeable Cd) in the soil and improved the quality of pakchoi,the Cd content in pakchoi stems and leaves was still over the limitation value of limited food contaminants(GB 2762-2005).