INGEIS   05370
INSTITUTO DE GEOCRONOLOGIA Y GEOLOGIA ISOTOPICA
Unidad Ejecutora - UE
artículos
Título:
Assesment of soil moisture influence on CO2 flux: a laboratory experiment.
Autor/es:
SANCI, R.; PANARELLO, H.O.; OSTERA, H. A.
Revista:
ENVIRONMENTAL GEOLOGY
Editorial:
Springer Verlag
Referencias:
Año: 2009 vol. 58 p. 491 - 497
ISSN:
0943-0105
Resumen:
Accurate measurements to assess the influence of soil moisture on CO2 flux requires the absolute estimates of soil CO2 flux. Thus, it was constructed a calibration system where CO2 with fixed concentration flowed through the different porous material. Previous to measurement, in order to verify the performance and reliability of a closed dynamic chamber, different discontinuous air-mixing rates and times were tested. The CO2 flux was estimated through sequential lectures and the best fit for flux measurements was obtained taking short readings every 3 min, during a total time of 12 min (R2 = 0.99). The best mixing rate was attained for 250 mL min-1, allowing 25 s of mixing previous to CO2 extraction for an infrared gas analyzer. The deviation of the measured values for dry sand from the reference CO2 flux (0.097 and 0.071 g m-2 min-1) was 5 and 7%. On dry sandy loam soil (SLS) the deviation was2%. The measured fluxes decreased 73 and 22% with content moisture of 20 and 10% (sand), and 78% with content moisture of 31% (SLS). This work allowed to estimate how much the measured emission rates deviate from the true ones for the specified chamber and sampling conditions.Keywords Soil CO2 flux - Calibration system -Closed dynamic chamber - Soil moisture