Pedogenic iron oxides (Fed) were quantified in 22 hematitic and goethitic soil samples (19 from oxic horizons; one from a plinthic horizon; one from a cambic horizon; one from saprolite) by use of two extraction procedures with sodium dithionite-citrate-bicarbonate (DCB). Approximately ninety percent of the Fed content was extracted at the first extraction by the DCB80 procedure. This procedure was more effective at extracting Fed than the DCB20, whose efficiency decreased with increasing Al3+-substitution in goethite. Compared with the DRX analysis, […]