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Oxygen Flux Measurement in Unsaturated Soils
Author(s) -
Rankin J. M.,
Sumner M. E.
Publication year - 1978
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/sssaj1978.03615995004200060005x
Subject(s) - microelectrode , current (fluid) , electrode , soil water , platinum , flux (metallurgy) , materials science , diffusion , abrasion (mechanical) , analytical chemistry (journal) , environmental science , soil science , chemistry , environmental chemistry , composite material , thermodynamics , metallurgy , physics , biochemistry , catalysis
Because in unsaturated soil systems the plateau of the current‐voltage curve is not well developed or is absent, O 2 reduction at the platinum microelectrode is not diffusion controlled and consequently measured current depends continuously on applied potential. To overcome this difficulty an O 2 flux meter has been designed which carefully controls and measures the applied potential and enables the effective potential at the electrode to be measured precisely. The instrument, which has facilities for measuring soil electrical resistance, electrode redox potential, and O 2 reduction current is fully described together with a circuit diagram. Because the surface oxide condition of the microelectrode is crucial to reproducible results, electrode pretreatment involving gentle abrasion in wet fine sand is necessary to standardize conditions prior to measurement. The results show that the instrument is suitable for measuring O 2 flux in unsaturated systems, and that measured current is closely related to soil airspace.