Gas chromatography and photoacoustic spectroscopy for the assessment of soil greenhouse gases emissions

Ciência Rural

Rodrigo Da Silveira Nicoloso²  Cimélio Bayer¹  Genuir Luis Denega¹  Paulo Armando Victória De Oliveira²  Martha Mayumi Higarashi²  Juliano Corulli Corrêa²  Letícia Dos Santos Lopes² 

[1] ,Embrapa Suínos e AvesConcórdia SC ,Brasil

关键词: no-tillage;    conventional tillage;    cover crops;    INNOVA 1412;    plantio direto;    preparo convencional;    plantas de cobertura;    INNOVA 1412;   

DOI  :  10.1590/S0103-84782013000200012

来源: SciELO

【 摘 要 】

Assessments of soil carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions are critical for determination of the agricultural practices' potential to mitigate global warming. This study evaluated the photoacoustic spectroscopy (PAS) for the assessment of soil greenhouse gases (GHG) fluxes in comparison to the standard gas chromatography (GC) method. Two long-term experiments with different tillage and cropping systems over a Paleudult were evaluated using static chambers. PAS measurements of CO2 and N2O concentrations showed good relationship and linearity (R2=0.98 and 0.94, respectively) with GC results. However, CH4 measurements were significantly affected by air sample moisture which interfered on CH4 detection by PAS. Overestimation of CO2 and N2O concentrations in air samples determined by PAS (14.6 and 18.7%, respectively) were also related to sampling moisture. CO2 and N2O fluxes showed good agreement between methods (R2=0.96 and 0.95, respectively), though PAS overestimated fluxes by 18.6 and 13.6% in relation to GC results, respectively. PAS showed good sensitivity and was able to detect CO2 and N2O fluxes as low as 332mg CO2 m-2 h-1 and 21µg N2O m-2 h-1. PAS analyzer should be detailed calibrated to reduce humidity interference on CO2, CH4 and N2O concentrations measurements avoiding overestimation or erroneous determination of soil GHG fluxes.

【 授权许可】

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