Applying abundant manure to soils can accelerate nitrogen (N) transformations and nitrous oxide (N₂O) emissions. We conducted a laboratory incubation to examine the turnover of labile N in manured soils. Soils were collected from agricultural fields that had recently received spring-injected liquid dairy manure with or without admixing nitrification inhibitors. Bands and interbands of the manure plots were incubated separately. Time courses of ammonium (NH₄⁺) and nitrate (NO₃⁻) were used to derive and contrast zero-, first-, and second-order kinetics models. We found that nitrification rates were consistently better represented by first-order kinetics (k₁). Furthermore, across all evaluated soils, the dependency of nitrification rate (k₁ of NH₄⁺) on initial NH₄⁺ concentration was modelled by Michaelis–Menten kinetics reasonably well, with an affinity (K_m) of 63 mg N·kg⁻¹ soil (R² = 0.82). Compared with the manure interbands, the initially NH₄-enriched bands had a much faster nitrification rate, with half-life for NH₄⁺ of only 4 d and rapid k₁ (0.186 versus 0.011 d⁻¹). Soil N substrate and k₁ exerted control on N₂O production. Nitrous oxide production increased linearly with both measured NH₄⁺ intensity (R² = 0.47) and modelled k₁–NH₄⁺ (R² = 0.48). Conversely, N₂O production increased non-linearly with NO₃⁻ intensity (R² = 0.68), where high NO₃⁻ caused a saturation plateau with a threshold of 96 mg N·kg⁻¹·d⁻¹ — beyond which no additional N₂O was produced. During peak N transformations, measured N₂O-N flux was 1.4% ± 0.3% of the inorganic N undergoing nitrification. Heavily manured soils exhibited augmented N turnover that increased N₂O fluxes, but inhibitors reduced these emissions by half.