An improved method for measuring soil <scp>N2O</scp> fluxes using a quantum cascade laser with a dynamic chamber

Cowan, Nicholas; Famulari, D.; Levy, Peter E.; Anderson, Margaret; Bell, M. J.; Rees, Robert M.; Reay, Dave; Skiba, U.

doi:10.1111/ejss.12168

Cited by 44 publications

(52 citation statements)

References 21 publications

(29 reference statements)

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“…Fluxes had returned to background levels (< 0.5 nmol m −2 s −1 ) within 28 days of each of the fertilisation events. Fluxes measured by all methods agreed reasonably well in magnitude, and there is no strong evidence for a systematic bias, given the differences in the spatial and temporal sampling (for a more specific insight see, e.g., Cowan et al, 2014a). The tillage event also produced an increase in emissions, and although the peak was less clearly defined, the effect was more prolonged.…”

Section: Comparison Of N 2 O Fluxes Measured From the Untilled And Timentioning

confidence: 62%

“…Static chamber measurements were made over a longer period than shown in this paper and are discussed in relation to a second tillage event by Drewer et al (2016). Fluxes were also measured using the QCL in a closed, dynamic chamber system (Cowan et al, 2014a). A chamber (39 cm inner diameter, 22 cm high) was placed onto a stainless steel collar inserted several centimetres into the soil (on average 5 cm) at least 15 min prior to measurement.…”

Section: Flux Measurementsmentioning

confidence: 99%

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The influence of tillage on N2O fluxes from an intensively managed grazed grassland in Scotland

et al. 2016

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Abstract. Intensively managed grass production in highrainfall temperate climate zones is a globally important source of N 2 O. Many of these grasslands are occasionally tilled to rejuvenate the sward, and this can lead to increased N 2 O emissions. This was investigated by comparing N 2 O fluxes from two adjacent intensively managed grazed grasslands in Scotland, one of which was tilled. A combination of eddy covariance, high-resolution dynamic chamber and static chamber methods was used.N 2 O emissions from the tilled field increased significantly for several days immediately after ploughing and remained elevated for approximately 2 months after the tillage event contributing to an estimated increase in N 2 O fluxes of 0.85 ± 0.11 kg N 2 O-N ha −1 . However, any influence on N 2 O emissions after this period appears to be minimal. The cumulative N 2 O emissions associated with the tillage event and a fertiliser application of 70 kg N ammonia nitrate from one field were not significantly different from the adjacent untilled field, in which two fertiliser applications of 70 kg N ammonia nitrate occurred during the same period. Total cumulative fluxes calculated for the tilled and untilled fields over the entire 175-day measurement period were 2.14 ± 0.18 and 1.65 ± 1.02 kg N 2 O-N ha −1 , respectively.

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Section: Comparison Of N 2 O Fluxes Measured From the Untilled And Timentioning

confidence: 62%

Section: Flux Measurementsmentioning

confidence: 99%

The influence of tillage on N2O fluxes from an intensively managed grazed grassland in Scotland

et al. 2016

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“…N 2 O flux measurements were made using a non-steady-state flow-through (or closed dynamic) chamber system which circulated air between a flux chamber and a quantum cascade laser (QCL) gas analyser via an air pump (SH-110, Varian Inc, CA, USA) (for a full description of the system see Cowan et al, 2014). A compact continuous wave QCL (CW-QC-TILDAS-76-CS, Aerodyne Research Inc., Billerica, MA, USA) was used to measure gas mixing ratios within the dynamic chamber system (with a detection limit of approximately 30 nmol mol −1 s −1 for N 2 O).…”

Section: Dynamic Chamber Methodsmentioning

confidence: 99%

“…In this experiment, a high precision dynamic chamber method (Cowan et al, 2014) was used to make 100 flux measurements of N 2 O from an intensively managed grassland field which contained several features associated with elevated N 2 O fluxes. Soil NH + 4 , NO − 3 , total carbon, total nitrogen, water filled pore space (WFPS%), bulk density and pH were recorded from 55 out of 100 flux measurement locations.…”

Section: N J Cowan Et Al: Spatial Variability and Hotspots Of Soilmentioning

confidence: 99%

Spatial variability and hotspots of soil N2O fluxes from intensively grazed grassland

et al. 2015

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and the high spatial variability of N 2 O flux across the field are shown to be linked to the distribution of waste from grazing animals and the resultant reactive nitrogen compounds in the soil which are made available for microbiological processes. Features within the field such as shaded areas and manure heaps contained significantly higher available nitrogen than the rest of the field. Although these features only represented 1.1 % of the area of the field, they contributed to over 55 % of the total estimated daily N 2 O flux.

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“…With this method of flux calculation, any non-linearity should be accounted for as far as possible. However, the time resolution (approximately 10 min) limits the detectable degree of non-linearity in the initial concentration change, so there remains some potential for underestimation of fluxes (Cowan et al, 2014a). q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q qqq q q q q q q q q q q qq q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q q …”

Section: Greenhouse Gas Exchangementioning

confidence: 99%

Nitrous oxide emissions from a peatbog after 13 years of experimental nitrogen deposition

et al. 2017

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Abstract. Nitrogen deposition was experimentally increased on a Scottish peatbog over a period of 13 years (2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015). Nitrogen was applied in three forms, NH 3 gas, NH 4 Cl solution, and NaNO 3 solution, at rates ranging from 8 (ambient) to 64 kg N ha −1 yr −1 , and higher near the NH 3 fumigation source. An automated system was used to apply the nitrogen, such that the deposition was realistic in terms of rates and high frequency of deposition events. We measured the response of nitrous oxide (N 2 O) flux to the increased nitrogen input. Prior expectations, based on the IPCC default emission factor, were that 1 % of the added nitrogen would be emitted as N 2 O. In the plots treated with NH + 4 and NO − 3 solution, no response was seen, and there was a tendency for N 2 O fluxes to be reduced by additional nitrogen, though this was not significant. Areas subjected to high NH 3 emitted more N 2 O than expected, up to 8.5 % of the added nitrogen. Differences in the response are related to the impact of the nitrogen treatments on the vegetation. In the NH + 4 and NO − 3 treatments, all the additional nitrogen is effectively immobilised in the vegetation and top 10 cm of peat. In the NH 3 treatment, much of the vegetation was killed off by high doses of NH 3 , and the nitrogen was presumably more available to denitrifying bacteria. The design of the wet and dry experimental treatments meant that they differed in statistical power, and we are less likely to detect an effect of the NH + 4 and NO − 3 treatments, though they avoid issues of pseudo-replication.

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An improved method for measuring soil N₂O fluxes using a quantum cascade laser with a dynamic chamber

Cited by 44 publications

References 21 publications

The influence of tillage on N<sub>2</sub>O fluxes from an intensively managed grazed grassland in Scotland

The influence of tillage on N<sub>2</sub>O fluxes from an intensively managed grazed grassland in Scotland

Spatial variability and hotspots of soil N<sub>2</sub>O fluxes from intensively grazed grassland

Nitrous oxide emissions from a peatbog after 13 years of experimental nitrogen deposition

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An improved method for measuring soil N2O fluxes using a quantum cascade laser with a dynamic chamber

Cited by 44 publications

References 21 publications

The influence of tillage on N&lt;sub&gt;2&lt;/sub&gt;O fluxes from an intensively managed grazed grassland in Scotland

The influence of tillage on N&lt;sub&gt;2&lt;/sub&gt;O fluxes from an intensively managed grazed grassland in Scotland

Spatial variability and hotspots of soil N&lt;sub&gt;2&lt;/sub&gt;O fluxes from intensively grazed grassland

Nitrous oxide emissions from a peatbog after 13 years of experimental nitrogen deposition

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An improved method for measuring soil N₂O fluxes using a quantum cascade laser with a dynamic chamber

The influence of tillage on N<sub>2</sub>O fluxes from an intensively managed grazed grassland in Scotland

The influence of tillage on N<sub>2</sub>O fluxes from an intensively managed grazed grassland in Scotland

Spatial variability and hotspots of soil N<sub>2</sub>O fluxes from intensively grazed grassland