Abstract

Closed static chambers are frequently adopted for estimating gas fluxes across environmental interfaces. In this study we assessed the effects of three gas sampling rates and two methods of chamber placement in fertirrigated soils for estimating nitrous oxide (N₂O) emissions, using chambers with similar design and on-site gas chromatography. The soils under analysis were fertirrigated with (liquid) digested swine manure at three different doses. The results indicate that N₂O flux estimates are firmly determined by the chosen sampling rate, chamber placement, chamber design, and the emission magnitude itself. N₂O fluxes were best estimated by faster sampling rates while gently placing the chamber at the soil surface due to conspicuous N₂O emissions and relatively small chamber volume. A generalized chamber accumulation model developed by normalizing the dataset was used to illustrate effects on expected “low unforced-chamber”, “high unforced-chamber” and “high forced-chamber” fluxes. We concluded that it is possible to adopt simple design and low-disturbing chambers with sufficient volume, height, and surface area for determining gaseous emissions across soil-air interfaces. Nevertheless, critical on-site gas sampling rate adjustment (by gas chromatography or other as precise real-time measuring device) is critical to avoid estimation inaccuracies in emission estimates.

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