Spatial Variability of Field‐Measured Denitrification Gas Fluxes

Abstract

The structure and magnitude of the spatial variability of N₂O and N₂O + N₂ fluxes were investigated along 12 transects of a Yolo loam (Typic Xerorthents) field site. The field‐measured N₂O and N₂O + N₂ fluxes were In‐normally distributed and exhibited large spatial variability. Calculated coefficients of variation ranged from 161 to 508% for the N₂O + N₂ fluxes and 282 to 379% for the N₂O fluxes. Analysis of autocorrelograms and partial autocorrelograms showed that in only 1 transect out of the 12 did the N₂O and N₂O + N₂ fluxes reveal any spatial dependence indicative of an autore‐gressive process. Thus, the denitrification flux values for this field site are considered to be spatially independent. With a knowledge of the frequency distribution and variances of the measured gas fluxes, it was calculated to require from 156 to 4117 N₂O + N₂ flux measurements and 350 N₂O flux measurements to estimate the “true” mean flux within ±10% of the estimated mean on a 3 by 36 m experimental plot.