Figure 2. Stoichiometric relationships between N₂O, CO₂, O₂ and urea-N input rate.

(a), N₂O emission as a function of urea-N input rate. (b), CO₂ emission as a function of urea-N input rate. (c), O₂ consumption as a function of urea-N input rate. In plot (c), NN and ND denote nitrifier nitrification and nitrifier denitrification, respectively. Note that O₂ consumption in the highest urea input treatment (U320) was not included due to the development of anaerobic conditions in the later stages of incubation and the units of x- and y-axis in plot (c) are different from plots (a & b).