镉污染土壤上施用沼液对生菜生长和土壤质量的影响

Effects of Biogas Slurry on Lettuce Growth and Cd-polluted Soil Quality

采用温室盆栽试验的方法研究了在两个镉污染水平土壤上施用沼液对生菜生长和土壤质量的影响。结果表明,生菜对土壤镉污染有一定的耐受性,在6 mg.kg-1和12 mg.kg-1镉处理土壤上可存活生长,但低镉土壤上生菜的地上部鲜干重均高于高镉土壤。沼液施用促进了生菜的生长,但促进作用在施用量为5 m l.次-1时最大。高水平镉污染促进了生菜体内硝酸盐的累积,而沼液只在高镉污染土壤上促进了硝酸盐的累积。高镉土壤中硝酸盐含量高于低镉土壤,沼液施用提高了土壤中硝酸盐含量和EC值,但只降低了高镉土壤上有效镉含量。该研究表明,沼液降低了镉对生菜的伤害,改变了土壤质量。

Effects of application of biogas slurry on lettuce growth and soil quality of Cd-contaminated soils were investigated by a greenhouse pot culture experiment.The results showed that lettuce had certain tolerance on soil Cd-contamination.Lettuce could survive and grow on two level Cd-contaminated soils（6 mg and 12 mg Cd per kilo of soil）.The shoot weight（fresh and dry） was higher for lettuces on low Cd-contaminated soil than high Cd-contaminated soil.Application of biogas slurry enhanced lettuce growth,and highest lettuce biomass was obtained at the application level of 5 mL biogas slurry each time irrespectively of Cd contamination levels.High Cd contamination increased nitrate concentration in lettuce,while biogas slurry application increased the nitrate concentration at high Cd contaminated soil.The results also showed that biogas slurry could reduce availability of Cd in soil,and so reduce the harm to the lettuce root.