Page 159 - Plant-Based Remediation Processes

150 T. Vamerali et al.

Fig. 8.5 Above-ground biomass ( S.E., n ¼ 3) of crops at flowering (above) and trees (without
leaves) 6 months after transplant (below) in pyrite waste under two tillages, in comparison with
uncontaminated ploughed controls. Percentage of reduction for ploughing and ripping against
control shown above bars. Small letters: statistically significant differences between treatments
within same species (Newman-Keuls test, P 0.05). Capital letters: statistically significant
differences between species for pyrite only (main effect)

Overall, tillage choice was not critical in terms of mass balance of phytoextraction
(Table 8.2), although we do recommend ripping to guarantee a better canopy cover
against pollutant dispersion and for easier mechanical management of biomasses,
e.g., cutting and harvesting operations. Among crops, fodder radish and sunflower
were the highest biomass-yielding species, the former reaching the greatest but still
poor metal removals (330 g ha 1 of metals). Fodder radish belongs to the