Influences of major nutrient elements on Pb accumulation of two crops from a Pb-contaminated soil

To know about the effect of major nutrient elements on various forms of Pb and metal extraction, a greenhouse experiment was conducted to assess the effects of various major nutrient elements on Pb accumulation in two crops (Spinacia oleracea, SO and Sonchus arvensis, SA) in Changchun, China. Results indicated that, for SO. the Pb concentrations in both shoots and roots had no difference with increasing nutrients except for low nutrient treatment (1/2H). For SA, high nutrient treatments (2H and 3H) resulted in higher Pb concentrations in roots than low and standard nutrient treatments (1/2H and C), but high Pb concentration in shoot appeared in low and highest nutrient treatments (1/2H and 3H). The nitrogenous nutrient treatment (2N) had the most effect of increasing Pb concentrations in roots of SO and SA. The potassic and phosphorus nutrient treatments (2K and 2P) had little effect on the Pb concentrations in plant tissues for SO. Pb concentration in SO was lower than SA. Because of the higher total biomass in SO than SA, the ability to Pb accumulation in SO was better than SA. Sequential extraction results indicated that the addition of soil amendments transform soil Pb from bioavailable fractions to non-bioavailable fraction substantially. The results suggest that nitrogen fertilizer for SO and phosphorus fertilizer for SA are the most effective materials for the remediation of Pb-contaminated soils, and increase the tolerance of crops to Pb contamination. (C) 2009 Elsevier B.V. All rights reserved.