Figure 2 : Percentage of α-glucosidase (AG), β-glucosidase (BG),
cellobiohydrolase (CB), β-xylosidase (BX), N-acetylglucosamine (NAG),
leucine aminopeptidase (LAP), and acid phosphatase (AP) activity below
20 cm in the top meter (A); and proportion of soil organic carbon (SOC),
microbial biomass (MB), sum of C-degrading enzymes (Csum= AG + BG + CB + BX), sum of nitrogen-mineralizing enzymes
(Nsum = NAG + LAP), and acid phosphatase (AP) below 20
cm in the top meter of soil among soil orders (B). Error bars show ± one
standard error of the mean (Figure panel A: n = 19; Figure panel B:
Inceptisol: n = 4, Mollisol: n = 5, Ultisol: n = 3).
Figure 3 : Correlations between soil and extracellular enzyme (EE)
stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) in surface
(< 20 cm depth) and subsoils (> 20 cm depth).
Blue lines show significant (α = 0.05) mixed-effects models of the
relationship between soil and EE stoichiometry (site was used as a
random effect; lines were not drawn where correlations were not
significant). Gray ribbons show the standard error of the model. Data
points represent individual soil samples (depths within each pit). Note
the scales of the axes differ among plots.