Just Accepted
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Are fans required for closed chamber N2O measurements in grazed pastures?
Donna Giltrap 
, Surinder Saggar, Peter Berben, Thilak Palmada
Abstract
Static chambers are the most common method for measuring nitrous oxide (N2O) and other greenhouse gas fluxes from soils in field conditions. However, there are no definitive guidelines on the use of fans to improve the mixing of air within chambers during sampling. In this study, we compared N2O fluxes following the application of a range of urine and nitrification inhibitor treatments to pasture soils using large (0.5 m2 footprint) static chambers both with and without the use of fans. Measurements were taken with and without fans from two experiments, each using a total of 56 chambers. In one of these experiments, the measurements were made at a time of low N2O fluxes, while in the other were made at a time of high N2O fluxes. Overall, both regression models and non-parametric methods found negligible effect of fan use on N2O measurements, although there could be a slight under-estimation of fluxes measured without fans under low emitting conditions. However, these results might not hold for systems with taller chambers containing more plant biomass or shorter measurement intervals.
SR24216 Accepted 16 May 2025
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