Fig. 3. (a) Nitrous oxide flux vs. time profile and for winter wheat–fallow under conventional tillage and as affected by N fertility (only low and high N regimes presented for clarity) and (b) soil water-filled pore space (WFPS) (mean of N levels ± S.E.) and soil temperature 20 mm below surface vs. time. Downward facing arrows and text indicate date, rate (kg N ha^–1), and method of N fertilization. Upward facing arrows indicate tillage events.