Figure 1. Soil gross and net N₂O fluxes.

Gross N₂O production (a), gross N₂O consumption (b), net N₂O flux (c), and the ratio of net N₂O flux to gross N₂O production (d), measured by ¹⁵N₂O pool dilution (¹⁵N₂OPD; red bars) and gas-flow soil core (GFSC; blue bars). For each method, means (± s.e., n = 4 replicate sampling points) with different capital (for ¹⁵N₂OPD) and small letters (for GFSC) indicate significant differences among sites (one-way ANOVA with Fisher’s LSD test at p ≤ 0.05 or Kruskal-Wallis ANOVA with multiple comparisons of mean ranks at p ≤ 0.05). For each site, asterisks above the bars indicate significant differences between the two methods (paired t test at p ≤ 0.05).