Fig. 2. Total dissolved organic (a) C and (b) N recoveries from fumigated and unfumigated soil extracts by persulfate digestion vs. high temperature catalytic oxidation (HTCO). Persulfate values are averages of three separate persulfate trials, three to five replicates per trial (n = 12–15), while HTCO values are single determinations. Vertical error bars are the standard deviations of all replicates taken together. Total observations = 25.