The soil used in this study was from a forest area in the North of
Portugal. The characteristics of the collected soil are described in
Table 1. Soil was collected randomly in the selected area, to a 20 cm
depth.
The soil was grinded to b2 mm, sterilized at 120 °C for 70 min in
two consecutive days to eliminate competing fungal species and
dried in an oven at 40 °C for 4 d. The soil was then amended with
Cd as cadmium chloride hemipentahydrate (CdCl2.2,5H2O). Solutions
of the salt were prepared with deionized water and applied to the soil
to obtain soil concentrations of 0, 15 and 30 mg Cd/kg dry soil
(mg kg−1). The treated soils were wetted for 1 week by adding deionized
water to maintain 60% of the water holding capacity; the soil
was then dried in the greenhouse for approximately 2 weeks. This
spiked soil was subjected to 3 cycles of wet and dry processes
(Blaylock et al., 1997).