Fig. 6 Mass-specific magnetic susceptibility ({chi}lf) as a function of time and temperature of exposure for forest topsoil (0–5 cm, 67 g kg-1 organic C, 12 g kg-1 Fe) and subsoil (5–15 cm, 20 g kg-1 organic C, 24 g kg-1 Fe) in Oven Experiment II. On the right for each treatment is the {chi}lf measured after 660 min exposure