3.3.3. Trace element concentrations
Cadmium, Zn, Cu and Pb concentrations were measured once
after 57 days of sowing because this was when Si concentrations
exhibited the largest differences between treatments, and
we assumed the potential effect on trace elements would be the
largest as well. Cadmium concentrations were lower in all soil solutions
from sown pots than in solutions from unsown pots for all ASi
treatments (Fig. 8), and Si showed no observable effect.
As for Cd, differences between treatments were not significant
for Zn, Pb and Cu. Zn concentrations in soil solutions increased
unevenly in all pots (without and with plants), with ASi treatments
(Table 6), while Cu concentrations decreased in pots without plants
in all ASi treatments. Zinc, Cu and Pb concentrations were higher in
both soil solutions without and with plants in the 15 ton ASi ha−1.