The availability and spatial distribution of oxygen (O₂) in agricultural soil are controlling factors in the production and emission of nitrous oxide (N₂O) to the atmosphere, but most experiments investigating the effects of various factors on N₂O emissions in soil have been conducted without determining the content and distribution of O₂. This complicates data interpretation and leads to speculative conclusions about which nitrogen transformation processes are responsible for N₂O production. Using an O₂-specific planar optode, this paper shows how spatiotemporal O₂ dynamics can be used to interpret data on N₂O emissions following a uniform or layered amendment of manure to agricultural soil. The spatial distribution of O₂ and gas emission rates were monitored for 12 h. An anoxic layer formed rapidly around the layered manure, whereas the uniformly distributed manure led to a more widespread anoxia. Nitrous oxide emissions increased immediately after depletion of O₂ in the manure-amended treatments. Greater understanding and improved knowledge of the spatial distribution of O₂ is clearly beneficial and can be used to devise improved application strategies for mitigating N₂O emissions from manure and other fertilizers.