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A CARBON DIOXIDE FLUX GENERATOR FOR TESTING INFRARED GAS ANALYZER‐BASED SOIL RESPIRATION SYSTEMS
Author(s) -
Martin Jonathan G.,
Bolstad Paul V.,
Norman John M.
Publication year - 2004
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2004.5140
Subject(s) - soil respiration , gas analyzer , carbon dioxide , flux (metallurgy) , respiration , environmental science , diffusion , spectrum analyzer , chemistry , soil water , soil science , environmental chemistry , botany , thermodynamics , physics , organic chemistry , biology , optics
An artificial flux generation device was developed to test the accuracy of a closed‐dynamic soil respiration system (LICOR 6400). The device consisted of an enclosed reservoir with a porous top; the reservoir contained a volume of CO 2 enriched air, which was monitored by an infrared gas analyzer (IRGA). When the internal CO 2 concentration within the reservoir was elevated, diffusion rates through the porous medium were measured by recording changes in CO 2 concentration within the reservoir. This diffusion‐based artificial flux mimics natural soil respiration, and allows an independent verification of the accuracy of soil respiration measurement systems. We tested a LI‐COR 6400 portable photosynthesis system fitted with a 6400‐09 soil CO 2 flux chamber. On average, this system overestimated high flux rates by 2 to 4% and underestimated low flux rates by 4 to 20% over five independent trials. Soil respiration appeared to be sensitive to boundary layer mixing, and ambient CO 2 concentrations.