The amended soils were prepared by uniformly mixing soil with SS or C in situ at a rate of 50 t ha−1 (dry weight) on 15 October 2012. Unamended soil is termed S hereafter, whilst soil amended with SS or C is termed S + SS and S + C. Soil samples of all treatments (~30 kg) were collected from the field (0–30 cm) and incubated outside undisturbed under environmental conditions in 60 × 40 × 25 cm trays at IRNASA (Salamanca, Spain) over the experimental period. Samples of unamended and amended soils were sieved (b2 mm) prior to their use in dissipation experiments.