Fig. 3 e Cd (a), Zn (b) and Pb (c) concentrations in rapeseed
(Brassica napus L.) shoots at the first and the second
harvests (4 and 12 weeks after sowing, respectively).
Values are average (n [ 5) ± standard deviation. Columns
with the same letter do not differ significantly at the 5%
level according to the Fisher’s multiple comparison test.
*No data are available for plants on the control and the
biochar-1% treated soils at the second harvest because all
plants had died.