Fig. 3. Environmental variables and N₂O fluxes during 2004 (mean ± standard error, n = 3). (a) Precipitation (cumulative during previous 10 d) and soil water content (0–10 cm), (b) air and soil (5-cm depth) temperatures, and N₂O fluxes in (c) anhydrous ammonia (AA), (d) urea ammonium nitrate (UAN), and (e) broadcast urea (BU) treated plots under conventional (CT), conservation (CsT), and no tillage (NT). Values in parentheses in (c–e) are mean soil NO₃^– concentrations (mg N kg^–1) over 0 to 20 cm across tillage treatments.