知识与财富的链接
为了比较等氮水平下不同有机肥及其与无机肥配施对土壤重金属的钝化效果,通过在0.2g·kg-1氮水平下单施商品有机肥、猪粪、牛粪、鸡粪和花生麸,及5种有机肥分别与无机肥(尿素+磷酸二氢钙+硫酸钾)配施(N:N=1:1)的盆栽试验,研究它们对重金属污染土壤上生菜(Lactuca sativa)生长及其Cd、Pb含量的影响。结果表明,与CK相比,有机肥可提高生菜的生物量(商品有机肥单施除外),有机肥单施时,鸡粪处理生菜的鲜重最高,配施时牛粪和鸡粪处理生菜的生物量最大。无论单施或配施,花生麸和鸡粪处理降低生菜地上部Cd含量的效果最好,且鸡粪较好地降低了生菜地上部Pb含量。牛粪和花生麸配施的Pb含量显著低于单施,猪粪和商品有机肥单施的Pb含量显著低于配施,其余单施和配施之间没有显著差异。因此,鸡粪是5种有机肥中较适合施用于重金属污染菜地土壤的有机肥。
A pot experiment was conducted to investigate the effects of five organic manures(commercial manure,pig shit,cattle shit,hen shit,earthnut residue)and their application combined with chemical fertilizers(1/2 organic manure + 1/2 chemical fertilizers,the composition of chemical fertilizers were N:P2O5:K2O =1:0.4:0.75)on the growth,Cd and Pb concentrations of lettuce(Lactuca sativa)under the condition of the same N leve(l0.2 g·kg-1).The results showed that compared with the control,the organic manures increased the fresh biomass of L.sativa except for the treatment of only commercial manure.Hen shit had the highest fresh biomass among the single addition of organic manures,and cattle shit and hen shit had high fresh biomass among the organic manures combined with chemical fertilizers.The Cd and Pb concentrations of lettuce abovegrounds,significantly lower than those of lettuce roots,were below 0.05 mg·kg-1,0.2 mg·kg-1 which were the Chinese food limit,respectively.There was a significantly positive relationship between Cd concentrations in lettuce aboveground and root,but there was no significant relationship for Pb concentrations.No matter organic manures were applied alone or combined with chemical fertilizers,earthnut residue and hen shit had the lowest aboveground Cd concentration of L.sativa,and hen shit had the lowest lettuce aboveground Pb concentration.There was no significant difference for aboveground Cd or Pb concentrations of lettuce between single treatment and combined treatment of organic manure except for lower Pb concentrations of single treatments of pig shit and commercial manure than combined treatments,and that of combined treatments of cattle shit and earthnut residue than single treatments.Therefore,among the 5 tested organic manures,hen shit was the most suitable amendment for the soil contaminated by heavy metal because of its largestbiomass,the lowest aboveground Cd or Pb concentration of lettuce,and invariable effect under the condition of single application or combination with chemical fertilizers.
