Fig. 5 Sorption and desorption of organic carbon (OC) on amorphous Al(OH)₃, goethite, and the 3Bw horizon of an Oxyaquic Dystrochrept. The sorption is given as the relationship between added and sorbed OC. The bars indicate subsequent desorption by different solutions for each dissolved organic carbon (DOC) addition. As the soil material contained indigenous OC, a line is given showing the course of soil OC content