紫云英对污染土壤上叶菜生长及其镉和铅含量的影响

为降低城郊菜地土壤叶菜可食部分Cd、Pb含量,通过3茬盆栽试验研究了紫云英(Astragalus sinicus L.)绿肥对重金属污染菜地上的叶菜生长、叶菜镉铅含量及土壤Cd、Pb活性形态(土壤溶液中Cd、Pb浓度及DTPA浸提态)的影响.结果表明,与对照相比,紫云英显著提高了供试生菜和苋菜的地上部生物量;但对DTPA-Cd和DTPA-Pb没有显著影响,对土壤溶液Cd、Pb浓度影响较小,没有显著影响供试生菜和苋菜地上部Cd、Pb含量.因而紫云英可以施用到供试菜地土壤上以提高叶菜产量,且不会提高叶菜Cd、Pb的食物链风险.

Effect of Astragalus sinicus on the growth, Cd and Pb concentration of leafy vegetables

In an effort to reduce Cd and Pb concentration in leafy vegetables grown in suburban soils, three rounds of pot experiments were conducted to study the effect of Astragalus sinicus L. on the growth, Cd and Pb concentration in leafy vegetables, and available heavy metals in the soil (e.g. Cd and Pb in soil solution, DTPA extractable metals). The results showed that compared with the control, A. sinicus significantly increased the aboveground biomass of Lactuca sativa and Amaranthus cruetus but there was no significant effect on Cd and Pb concentration in DTPA extractable fraction, in soil solution or in the vegetables. Therefore, A. sinicus can be applied to increase the biomass of leafy vegetables in the test soil without increasing the risk of food chain contamination.