Nitrous Oxide Flux from Poultry‐Manured Erosion Plots and Grass Filters after Simulated Rain

Abstract

Abstract Adding carbon‐rich materials to fields, like manure, may enhance denitrification. Grass filters, which are used to trap surface runoff from these fields, may also provide a carbon‐rich environment that favors water infiltration and denitrification. Nitrous oxide (N 2 O) may be evolved these settings. It is a radiatively important trace gas and intermediate in the denitrification pathway and several other microbial processes. We measured N 2 O flux, after simulated rain, using a soil cover technique in poultry‐manured plots and grass filters receiving their runoff. Intact soil cores were used to relate the N 2 O flux to the denitrification potential of the plots. Nitrous oxide fluxes were smaller in grass filters than in manured plots, even though more denitrifying bacteria were present. The average N 2 O flux in the three most dynamic erosion plots was 755 µg N 2 O‐N m −2 h −1 , which was 39% of the maximal denitrification rate measured in acetylene‐blocked, NO − 3 ‐amended soil cores. Nitrous oxide flux immediately after rainfall was greater than N 2 O flux measurements reported for similar agricultural settings.