Fig. 4. Degradation rate constants (d^-1) of dissolved organic carbon (DOC) and concentration of DOC (right scale) in extracts obtained through suspension in ground water (soil/water ratio 1:3) of forest floor materials taken from poorly drained (PD) and moderately well-drained (MWD) sections of the riparian forest. The DOC extracts were amended with NH₄ (0.5 mg NH₄-N L^-1) and incubated aerobically in the dark for 14 d.